Incidence of the tensor of the vastus intermedius: A cadaveric study

INTRODUCTION

The quadriceps femoris muscle is present in the anterior region of the thigh and is classically described as a muscle with four heads: rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. A few years ago, a "fifth head" was described and named the tensor of the vastus intermedius (TVI). The TVI belly is in line with the belly of the vastus lateralis, and its aponeurosis imposes considerable tension on the vastus intermedius, medializing its action, to play a significant role in knee extension.

OBJECTIVE

To perform a study of the TVI incidence in a Brazilian population and describe its variations.

MATERIAL AND METHODS

We dissected lower limbs from cadavers previously fixed in 10% formaldehyde, belonging to the Laboratory of Anatomy of the Department of Morphology of the Biosciences Center of the Federal University of Rio Grande do Norte.

RESULTS

Eighty-one lower limbs were analyzed with only 33 (40.74%) of them presenting TVI. All four types of TVI described by the literature were present in our sample with the following distribution: type 1 with 15.15%; type 2 with 9.1%; type 3 with 33.33%; type 4 with 42.42%.

DISCUSSION

Although the literature points to the TVI as a normal belly of the quadriceps, making it a "quinticeps", our analysis points to the TVI as a variation and probably a matter of regionality. However, the presence of TVI is not a rare case and cannot be disregarded, which makes this study important for anatomists, physiotherapists, physicians, and surgeons.

Nuclear organization and morphology of cholinergic neurons in the brain of the rock cavy (Kerodon rupestris) (Wied, 1820)

The aim of this study was to conduct cytoarchitectonic studies and choline acetyltransferase (ChAT) immunohistochemical analysis to delimit the cholinergic groups in the encephalon of the rock cavy (Kerodon rupestris), a crepuscular Caviidae rodent native to the Brazilian Northeast. Three young adult animals were anesthetized and transcardially perfused. The encephala were cut in the coronal plane using a cryostat. We obtained 6 series of 30-μm-thick sections. The sections from one series were subjected to Nissl staining. Those from another series were subjected to immunohistochemistry for the enzyme ChAT, which is used in acetylcholine synthesis, to visualize the different cholinergic neural centers of the rock cavy. The slides were analyzed using a light microscope and the results were documented by description and digital photomicrographs. ChAT-immunoreactive neurons were identified in the telencephalon (nucleus accumbens, caudate-putamen, globus pallidus, entopeduncular nucleus and ventral globus pallidus, olfactory tubercle and islands of Calleja, diagonal band of Broca nucleus, nucleus basalis, and medial septal nucleus), diencephalon (ventrolateral preoptic, hypothalamic ventrolateral, and medial habenular nuclei), and brainstem (parabigeminal, laterodorsal tegmental, and pedunculopontine tegmental nuclei). These findings are discussed through both a functional and phylogenetic perspective.

Retinofugal Projections Into Visual Brain Structures in the Bat Artibeus planirostris: A CTb Study

A well-developed visual system can provide significant sensory information to guide motor behavior, especially in fruit-eating bats, which usually use echolocation to navigate at high speed through cluttered environments during foraging. Relatively few studies have been performed to elucidate the organization of the visual system in bats. The present work provides an extensive morphological description of the retinal projections in the subcortical visual nuclei in the flat-faced fruit-eating bat (Artibeus planirostris) using anterograde transport of the eye-injected cholera toxin B subunit (CTb), followed by morphometrical and stereological analyses. Regarding the cytoarchitecture, the dorsal lateral geniculate nucleus (dLGN) was homogeneous, with no evident lamination. However, the retinal projection contained two layers that had significantly different marking intensities and a massive contralateral input. The superior colliculus (SC) was identified as a laminar structure composed of seven layers, and the retinal input was only observed on the contralateral side, targeting two most superficial layers. The medial pretectal nucleus (MPT), olivary pretectal nucleus (OPT), anterior pretectal nucleus (APT), posterior pretectal nucleus (PPT) and nucleus of the optic tract (NOT) were comprised the pretectal nuclear complex (PNT). Only the APT lacked a retinal input, which was predominantly contralateral in all other nuclei. Our results showed the morphometrical and stereological features of a bat species for the first time.

The Suprachiasmatic Nucleus and the Intergeniculate Leaflet of the Flat-Faced Fruit-Eating Bat (Artibeus planirostris): Retinal Projections and Neurochemical Anatomy

In mammals, the suprachiasmatic nucleus (SCN) and the intergeniculate leaflet (IGL) are the main components of the circadian timing system. The SCN, classically known as the master circadian clock, generates rhythms and synchronizes them to environmental cues. The IGL is a key structure that modulates SCN activity. Strategies on the use of time by animals can provide important clues about how some species are adapted to competitive process in nature. Few studies have provided information about temporal niche in bats with special attention on the neural substrate underlies circadian rhythms. The aim of this study was to investigate these circadian centers with respect to their cytoarchitecture, chemical content and retinal projections in the flat-faced fruit-eating bat (Artibeus planirostris), a chiropteran endemic to South America. Unlike other species of phyllostomid bats, the flat-faced fruit-eating bat's peak of activity occurs 5 h after sunset. This raises several questions about the structure and function of the SCN and IGL in this species. We carried out a mapping of the retinal projections and cytoarchitectural study of the nuclei using qualitative and quantitative approaches. Based on relative optical density findings, the SCN and IGL of the flat-faced fruit-eating bat receive bilaterally symmetric retinal innervation. The SCN contains vasopressin (VP) and vasoactive intestinal polypeptide (VIP) neurons with neuropeptide Y (NPY), serotonin (5-HT) and glutamic acid decarboxylase (GAD) immunopositive fibers/terminals and is marked by intense glial fibrillary acidic protein (GFAP) immunoreactivity. The IGL contains NPY perikarya as well as GAD and 5-HT immunopositive terminals and is characterized by dense GFAP immunostaining. In addition, stereological tools were combined with Nissl stained sections to estimate the volumes of the circadian centers. Taken together, the present results in the flat-faced fruit-eating bat reveal some differences compared to other bat species which might explain the divergence in the hourly activity among bats in order to reduce the competitive potential and resource partitioning in nature.

Nuclear organization of the substantia nigra, ventral tegmental area and retrorubral field of the common marmoset (Callithrix jacchus): A cytoarchitectonic and TH-immunohistochemistry study

It is widely known that the catecholamine group is formed by dopamine, noradrenaline and adrenaline. Its synthesis is regulated by the enzyme called tyrosine hydroxylase. 3-hydroxytyramine/dopamine (DA) is a precursor of noradrenaline and adrenaline synthesis and acts as a neurotransmitter in the central nervous system. The three main nuclei, being the retrorubral field (A8 group), the substantia nigra pars compacta (A9 group) and the ventral tegmental area (A10 group), are arranged in the die-mesencephalic portion and are involved in three complex circuitries - the mesostriatal, mesolimbic and mesocortical pathways. These pathways are involved in behavioral manifestations, motricity, learning, reward and also in pathological conditions such as Parkinson's disease and schizophrenia. The aim of this study was to perform a morphological analysis of the A8, A9 and A10 groups in the common marmoset (Callithrix jacchus - a neotropical primate), whose morphological and functional characteristics support its suitability for use in biomedical research. Coronal sections of the marmoset brain were submitted to Nissl staining and TH-immunohistochemistry. The morphology of the neurons made it possible to subdivide the A10 group into seven distinct regions: interfascicular nucleus, raphe rostral linear nucleus and raphe caudal linear nucleus in the middle line; paranigral and parainterfascicular nucleus in the middle zone; the rostral portion of the ventral tegmental area nucleus and parabrachial pigmented nucleus located in the dorsolateral portion of the mesencephalic tegmentum. The A9 group was divided into four regions: substantia nigra compacta dorsal and ventral tiers; substantia nigra compacta lateral and medial clusters. No subdivisions were made for the A8 group. These results reveal that A8, A9 and A10 are phylogenetically stable across species. As such, further studies concerning such divisions are necessary in order to evaluate the occurrence of subdivisions that express DA in other primate species, with the aim of characterizing its functional relevance.

Neuropeptide S counteracts 6-OHDA-induced motor deficits in mice

Neuropeptide S (NPS) is a 20-aminoacid peptide that selectively activates a G-protein coupled receptor named NPSR. Preclinical studies have shown that NPSR activation promotes anxiolysis, hyperlocomotion, arousal and weakfullness. Previous findings suggest that dopamine neurotransmission plays a role in the actions of NPS. Based on the close relationship between dopamine and Parkinson disease (PD) and on the evidence that NPSR are expressed on brain dopaminergic nuclei, the present study investigated the effects of NPS in motor deficits induced by intracerebroventricular (icv) administration of the dopaminergic neurotoxin 6-OHDA in the mouse rotarod test. 6-OHDA injection evoked motor deficits and significantly reduced tyrosine hidroxylase (TH)-positive cells in the substantia nigra (SN) and ventral tegmental area. However, a positive correlation was found only between the motor performance of 6-OHDA-injected mice and the number of TH-positive cells in SN. The systemic administration of l-DOPA+benserazide (25+6.25 mg/kg) counteracted 6-OHDA-induced motor deficits in mice. Similar to L-DOPA, the icv injection of NPS (0.1 and 1 nmol) reversed motor deficits evoked by 6-OHDA. In conclusion, NPS attenuated 6-OHDA-induced motor impairments in mice assessed in the rota-rod test. We discussed the beneficial actions of NPS based on a putative facilitation of dopaminergic neurotransmission in the brain. Finally, these findings candidate NPSR agonists as a potential innovative treatment for PD.

Spinal projections of the A5, A6 (locus coeruleus), and A7 noradrenergic cell groups in rats

The pontine noradrenergic cell groups, A5, A6 (locus coeruleus), and A7, provide the only noradrenergic innervation of the spinal cord, but the individual contribution of each of these populations to the regional innervation of the spinal cord remains controversial. We used an adeno-associated viral (AAV) vector encoding green fluorescent protein under an artificial dopamine beta-hydroxylase (PRSx8) promoter to trace the spinal projections from the A5, A6, and A7 groups. Projections from all three groups travel through the spinal cord in both the lateral and ventral funiculi and in the dorsal surface of the dorsal horn, but A6 axons take predominantly the dorsal and ventral routes, whereas A5 axons take mainly a lateral and A7 axons a ventral route. The A6 group provides the densest innervation at all levels, and includes all parts of the spinal gray matter, but it is particularly dense in the dorsal horn. The A7 group provides the next most dense innervation, again including all parts of the spinal cord, but is it denser in the ventral horn. The A5 group supplies only sparse innervation to the dorsal and ventral horns and to the cervical and lumbosacral levels, but provides the densest innervation to the thoracic intermediolateral cell column, and in particular to the sympathetic preganglionic neurons. Thus, the pontine noradrenergic cell groups project in a roughly topographic and complementary fashion onto the spinal cord. The pattern of spinal projections observed suggests that the locus coeruleus might have the greatest effect on somatosensory transmission, the A7 group on motor function, and the A5 group on sympathetic function.

Expression of cocaine- and amphetamine-regulated transcript in the rat forebrain during postnatal development

Cocaine- and amphetamine-regulated transcript (CART) is widespread in the rodent brain. CART has been implicated in many different functions including reward, feeding, stress responses, sensory processing, learning and memory formation. Recent studies have suggested that CART may also play a role in neural development. Therefore, in the present study we compared the distribution pattern and levels of CART mRNA expression in the forebrain of male and female rats at different stages of postnatal development: P06, P26 and P66. At 6 days of age (P06), male and female rats showed increased CART expression in the somatosensory and piriform cortices, indusium griseum, dentate gyrus, nucleus accumbens, and ventral premammillary nucleus. Interestingly, we found a striking expression of CART mRNA in the ventral posteromedial and ventral posterolateral thalamic nuclei. This thalamic expression was absent at P26 and P66. Contrastingly, at P06 CART mRNA expression was decreased in the arcuate nucleus. Comparing sexes, we found increased CART mRNA expression in the anteroventral periventricular nucleus of adult females. In other regions including the CA1, the lateral hypothalamic area and the dorsomedial nucleus of the hypothalamus, CART expression was not different comparing postnatal ages and sexes. Our findings indicate that CART gene expression is induced in a distinct temporal and spatial manner in forebrain sites of male and female rats. They also suggest that CART peptide participate in the development of neural pathways related to selective functions including sensory processing, reward and memory formation.

Cocaine- and amphetamine-regulated transcript is overexpressed in the anteroventral periventricular nucleus of pregnant rats

The anteroventral periventricular nucleus (AVPV) is sexually dimorphic, presenting a higher neuronal density in females. The AVPV contains a dense collection of oestrogen and progesterone receptors and has been related to the modulation of gonadotrophin-releasing hormone (GnRH) secretion and gene expression in response to circulating hormonal levels. It has been suggested that cocaine- and amphetamine-regulated transcript (CART) is also related to reproductive control because CART immunoreactive fibres are in close apposition with GnRH neurones. A portion of these fibres originate in the AVPV but its role in mediating hormonal action needs to be better explored. We hypothesised that CART expression in the AVPV would be influenced by the reproductive state and, consequently, by hormonal levels. To test this hypothesis, we analysed CART expression in the AVPV of female rats in different reproductive states (pro-oestrous, pregnancy and lactation). We found that, on the 19th day of pregnancy, female rats presented increased CART expression. Our findings indicate that AVPV CART expression is influenced by the reproductive state and that CART neurones in the AVPV may play a role in the hormonal mechanisms involved in the induction of maternal behaviour.

Female odors stimulate CART neurons in the ventral premammillary nucleus of male rats

Olfactory information is known to influence both male and female sexual behavior. Chemosensory compounds known as pheromones activate distinct brain pathways, inducing innate and stereotyped behaviors, as well as hormonal changes. Studies have shown that female odors induce Fos expression in various brain nuclei of conspecific males, including the ventral premammillary nucleus (PMV). Although poorly investigated, previous studies have suggested that the PMV plays a role in aggressive and sexual behavior. In this study, we used Fos protein expression as a marker for neurons responsive to female odors in sexual inexperienced male rats exposed to soiled bedding. We observed that female odors induced intense Fos immunoreactivity throughout the PMV. Most of these neurons also express cocaine- and amphetamine-regulated transcript (CART) immunoreactivity. In addition, we used in situ hybridization and observed that, following exposure to female odors, CART mRNA increased only in the ventral PMV. Our results suggest that female odors stimulate CART production in the PMV of inexperienced males. Considering that the PMV CART neurons also express the leptin receptor, as well as the fact that they project to areas related to reproduction, we hypothesize that PMV CART neurons integrate nutritional and environmental (olfactory) information, being apt to modulate male reproductive behavior.

Short stature, obesity and arterial hypertension in a very low income population in North-eastern Brazil

BACKGROUND AND AIM

This cross-sectional study involved the adult population (age >18 and <60 years) of a 315-shack slum on the outskirts of the city of Maceió in North-eastern Brazil. The purpose was to investigate whether short stature in adults (an indicator of undernutrition in early life) is associated with arterial hypertension and obesity.

METHODS AND RESULTS

We collected the subjects socio-economic data, and arterial hypertension (AH), weight, height, waist circumference and waist/hip (W/H) circumference ratio measurements. Hypertension was diagnosed as diastolic AH f 90 mmHg and/or systolic AH f 140 mmHg. The body mass index (BMI) was used to determine nutritional status, with overweight/obesity being defined on the basis of a cut-off point of 25 kg/m2. A W/H ratio of f 0.80 for women or f 0.95 for men was considered indicative of abdominal obesity. Short stature was defined as falling into the 1st quartile (Q) of height distribution. Hypertension was prevalent in 28.5% of the population (women=38.5%; men=18.4%). The systolic and diastolic AH readings were significantly higher in women in the 1st Q than in those in the 4th Q, and the same was true of W/H. The prevalence of hypertension was statistically significant for the first two Q's in comparison with the last two: 22.1% vs 14.6% (men), and 42.4% vs 34.6% (women). Hypertension was more prevalent in women who were obese and short (50%) than in those who were obese but not short (OR=1.98; CI=1.22-2.96).

CONCLUSIONS

Living conditions were extremely precarious and the prevalence of hypertension was quite high. Stature negatively correlated with hypertension and overweight in women but not in men.

Food consumed does not account for the higher prevalence of obesity among stunted adults in a very-low-income population in the Northeast of Brazil (Maceió, Alagoas)

OBJECTIVE

To study the food pattern of stunted and nonstunted, obese and nonobese individuals in a very-low-income population.

DESIGN

A household survey.

SETTING

Slum set up by the 'Homeless Movement', city of Maceió (Alagoas), Brazil.

SUBJECTS AND METHODS

A total of 532 adults classified by sex, stature (Z</= and Z > -2s.d. of the NCHS curves), and body mass index (BMI) were compared using the following variables: waist circumference, waist-hip circumference ratio (W/H), percentage body fat (skinfold thickness and bioelectrical impedance), and food intake (24-h recall).

RESULTS

The prevalence of stunting was 22.6%. In all, 30% of the stunted subjects were overweight or obese, compared with 23% for the nonstunted individuals (P<0.05). In women, logistic regression analysis showed a strong association among weight, abdominal fat, and stunting (r=0.81). No significant differences were observed in the values of W/H or in the qualitative menu of the different categories. Energy intake was below the RDA figures (about 63%). There was similarity among the groups regarding the proportion of macronutrients, except for the fact that stunted obese women ingested less fat and protein than nonstunted obese women. Stunted obese individuals consumed less energy (5962 kJ) than the population as a whole (6213 kJ), an amount far lower than their average needs, which were calculated on the basis of their shorter stature (8109 kJ).

CONCLUSION

The observed energy consumption seems compatible with the panorama of undernutrition present in the population, but it does not explain the high prevalence of obesity detected.

Obesity and undernutrition in a very-low-income population in the city of Maceió, northeastern Brazil

Obesity is the nutritional disorder which has shown the greatest increase in prevalence, even in those countries in which deficiency diseases represent a severe public health problem. The goal of the present study was to analyse the anthropometric profile of a community living in the outskirts of Maceió, capital of Alagoas (northeastern Brazil), and to investigate the hypothesis of a coexistence of undernutrition and obesity in a very low-income population. The survey was conducted on 315 families (1247 individuals). Among the children (aged < or =10 years), the prevalence of wasting, stunting and wasting plus stunting was 3.8, 8.3 and 8.7 % respectively. Wasting (10.2 %) was the most prevalent form of undernutrition among adolescents; nonetheless, a higher frequency of stunting (11 %) and overweight-obesity (5.5 %) was seen specifically in girls, in agreement with trends found in other studies. Adults exhibited a high prevalence of overweight-obesity (25 %), but stunting was also present (22 %). Of the stunted individuals, 30 % were overweight-obese and 16.3 % were underweight. There were eighty-six families with at least one parent who was underweight (27 %) and 104 families with at least one parent who was overweight (33 %). Underweight and overweight-obesity were both present in ninety-six households (30 %). These results may indicate that better living conditions in urban areas in a population 'adapted' to chronic famine might increase the susceptibility to obesity. Considering the harm caused by the cumulative effect of these two conditions (undernutrition in childhood and obesity in adult life) there is a clear need for new studies to uncover the determinant factors so that preventive measures can be implemented.