A microscopic survey of the human temporomandibular joint disc

The articular disc of the temporomandibular joint was studied in a foetuses and children group (GI), a dentate group of adults (GII) and an edentulous, elderly group of humans (GIII) by light microscopy. The main, constituent bundles of type I collagen fibres are stratified and are orientated sagittally, transversely and obliquely in the middle portion of the disc. In the thick, posterior portion, transverse bundles constitute the main feature. In the anterior portion of the disc, the fibres are sagittally and obliquely orientated. Type III. collagen fibres, intermingled with type I collagen fibres are present in all groups. The disc is cellular in nature in foetuses and children becoming more fibrous with age. Chondroid cells are observed in all portions of the discs in groups GII and GIII. Elastic fibres are numerous in GI discs and decrease in number in the disc with age. These fibres lie parallel to the collagen fibres in all three portions of the three groups.

Hereditary equine regional dermal asthenia in three related Quarter horses in Brazil

Hereditary equine regional dermal asthenia belongs to a group of inherited, congenital connective tissue dysplasias usually described as hyperelastosis cutis, cutaneous asthenia, dermatosparaxis, or Ehlers-Danlos-like syndrome. This report presents the clinical and histological features of three related Quarter horses affected with regional dermal asthenia. These horses had bilateral asymmetric lesions of the trunk and lumbar regions, where the skin was hyperextensible. Handling of the skin elicited a painful response and superficial trauma led to skin wounds. The skin was thinner than normal in the affected areas, with thickened borders and harder fibrotic masses (pseudotumours). The histopathological findings included thinner and smaller collagen fibrils, and a loose arrangement of collagen fibres in the middle, adventitial and deep dermis. Masson's trichrome and Calleja stains did not reveal any abnormality of collagen and elastic fibres. Electron microscopy showed no abnormalities. As in human patients, pseudotumour histopathological findings included fibroplasia and neovascularization. The pedigree chart of these animals supports an autosomal recessive type of inheritance, which has been suggested by other studies. This is the first report of this disease in Brazil. Its clinical and histological features resemble those described in horses affected with this condition in the United States.

Nanocellulose from Curava Fibers and their Nanocomposites

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

HISTOCHEMICAL RESPONSES of RATS EXERCISED IN TWO WEEKLY FREQUENCIES and INGESTING STANDARD OR HYPERCALORIC DIET

This study investigated if overfed rats present morphological and histochemical muscle adaptation similar to normally fed, both submitted to two different weekly frequencies of training. Thirty male Wistar rats were fed either with standard chow (SCO) or with hypercaloric diet (HCO). They were subdivided into six subgroups: sedentary (SCO and HCO), trained twice/week (SC2 and HC2) and trained five times/week (SC5 and HC5). The trained groups swam 60 min/day, during 10 weeks. Twenty four hours after the last training, samples of Gastrocnemius were excised and stained with HE, NADH-TR and m-ATPase, and the capillary density was calculated. Total heart mass (HM) and the mass of atrium (AM), left (LV) and right (RV) ventricles were excised and weighted. The comparisons were made by ANOVA and by Covariance analysis, adjusting the variables by body weight. The results showed that the HCO achieved higher BM, however, absolute HM did not differ post training. Irrespective of the diet, rats that were trained twice a week presented significantly greater increase in the AM. In general, the SC5 and HC5 groups showed higher HM, LV, RV, proportion of oxidative fibres and capillary density, compared to the sedentary and twice week trained groups. A higher proportion of injuries (splitting) was noted in the HC2 and HC5 compared to SC2 and SC5. These results indicate that the frequency of training influenced the skeletal and heart adaptation and larger changes were observed in the 5x/week group, which ingested the standard diet. The 5x/week training groups also presented large amount of muscle fibres damage.

Development of Intra- and Interxylary Secondary Phloem in Coccinia indica (Cucurbitaceae)

Stern anatomy and the development of intraxylary phloem were investigated in six to eight years old Coccinia indica L. (Cucurbitaceae). Secondary growth in the stems was achieved by the normal cambial activity. In the innermost part of the thicker stems, xylem parenchyma and pith cells dedifferentiated into meristematic cells at several points. In some of the wider rays, ray cells dedifferentiate and produce secondary xylem and phloem with different orientations and sometimes a complete bicollateral vascular bundle. The inner cambial segments of the bicollateral vascular bundle (of primary growth) maintained radial arrangement even in the mature stems but in most places the cambia were either inactive or showed very few cell divisions. Concomitant with the obliteration and collapse of inner phloem (of bicollateral vascular bundles), parenchyma cells encircling the phloem became meristematic forming a circular sheath of internal cambia. These internal cambia produce only intraxylary secondary phloem centripetally and do not produce any secondary xylem. In the stem, secondary xylem consisted mainly of axial parenchyma, small strands of thick-walled xylem derivatives, i.e. vessel elements and fibres embedded in parenchymatous ground mass, wide and tall rays along with exceptionally wide vessels characteristic of lianas. In thick stems, the axial parenchyma de-differentiated into meristem, which later re-differentiated into interxylary phloem. Fibre dimorphism and pseudo-vestured pits in the vessels are also reported.

Development of successive cambia and structure of wood in Gallesia integrifolia (Spreng.) Harms (Phytolaccaceae)

Stem diameter in Gallesia integrifolia (Spreng.) Harms (Phytolaccaceae) increases by forming concentric rings of xylem alternating with phloem, which show frequent anastomoses. After a period of primary growth and the formation of first (normal) ring of vascular cambium, further successive rings are initiated outside this cambium. The second ring of cambium originates from the pericycle parenchyma located between the proto-phloem, and the pericycle fibres. Each cambium produces centripetally secondary xylem and centrifugally secondary phloem. Differentiation of xylem precedes that of phloem and the first elements formed are always xylem fibres. Structurally, the vascular cylinder is composed by successive rings of secondary xylem and phloem. These rings are separated by wide bands of conjunctive parenchyma tissue. Presence of collateral vascular bundles with irregular orientation is observed in the region of anastomoses of two or more bands of conjunctive tissue. These bundles are surrounded by isodiametric, lignified and thick-walled cells. In some of the cambial rings, occurrence of polycentric rays was also noticed; these rays are tall, and characterized by the presence of meristematic regions that differentiated into thick-walled elements of secondary xylem. Origin and development of the successive cambia and the structure of xylem are discussed.

On the cardiac control in the South American lungfish, Lepidosiren paradoxa

1. 1. The mechanisms behind cardiac control were investigated in the South American lungfish, Lepidosiren paradoxa, using fish with chronically implanted cannulae and electromagnetic flow probes. In addition, a preliminary study was made of the cardiovascular events associated with air breathing. 2. 2. The study suggests that the heart of Lepidosiren is controlled by cholinergic vagal fibres which, in some animals, exert a tonic influence in the resting fish. Cyclic changes in heart rate in association with air breaths is due to modulation of this cholinergic tonus. 3. 3. In addition to the variable cholinergic tonus, there appears to be a relatively stable adrenergic tonus on the heart, which causes an elevated heart rate. The adrenergic tonus is likely to be due to local release of catecholamines from endogenous chromaffin cells within the atrium. 4. 4. Preliminary results suggest that pulmonary arterial flow increases by about 50% immediately following an air breath. The mechanism behind this increase probably involves both an elevation of the heart rate and a redistribution of blood flow into the pulmonary circuit. © 1989.

Cassava bagasse as a dietary food product

Cassava bagasse, the solid residue of the starch industry, was studied as a potential ingredient in high-fibre dietary products. The bagasse contained 80% of starch, 11.5% fibre, 1.14% ash and 0.85% of protein, and it had a pH of 5.8. Glucose was the major sugar and the hemicellulose content was 22.31%. Microscopic analysis of the bagasse revealed a large number of starch granules inside the parenchyma cells and fibres, as well as outside the cells. The bagasse may be used in high-fibre products, and total or partial hydrolysis of its starch content might increase its commercial value.

Morphological aspects of the mid-palatal suture in the human foetus: A light and scanning electron microscopy study

Morphological features of the mid-palatal suture were studied in human foetuses from 4 to 9 months of intra-uterine life. The foetuses were divided into three age groups, GI (16-23 weeks), GII (24-31 weeks) and GIII (32-39 weeks). The mid-palatal suture in GI foetuses is rectilineal in form with a wide space between the palatal processes of the maxilla. The suture has a sinuous nature in GII and GIII foetuses due to growth of the bone processes crossing the mid-line. A wide zone of cellular proliferation observed in GI narrows in GII and GIII foetuses. The imbricating nature of the suture in GII and GIII is caused by bone growth adjacent to the mid-palatal suture. Sharpey's fibres, emerging from the bone processes, run to the median region of the mid-palatal suture and are observed from GI foetuses onwards. The collagen fibres of the mid-palatal suture are orientated transversely under the oral epithelium and exhibit a regular meshwork with a predominance of sagittal fibres in the median region of the suture. These fibres are orientated transversely and obliquely at the junction with the nasal septum.

Apoptosis in the early developing periodontium of rat molars

Development of the periodontium involves a series of complex steps that result in the formation of root dentine, cementum, bone and fibres of the ligament. These precisely controlled and timed events require the participation of the enamel organ derived epithelial cells of Hertwig's (HRS) and ectomesenchymal cells of the dental follicle. These events involve rapid turnover of the tissues and cells, including disappearance of epithelial cells of HRS. Thus, it seemed likely to us that programmed cell death (apoptosis) may play a role in the development of the periodontium. Fragments of first molars, obtained from 14- and 29-day-old rats, were fixed in glutaraldehyde-formaldehyde and processed for light and electron microscopy. For the TUNEL method for detection of apoptosis, specimens were fixed in 4% formaldehyde and embedded in paraffin. Results confirmed that epithelial cells of HRS maintain a close relationship with the forming dentine root, and that they may become trapped in the dentino-cemental junction. Some of the epithelial cells exhibited ultrastructural features which are consistent with the interpretation that they were undergoing programmed cell death, i.e. apoptosis. Periodontal fibroblast-like cells showed typical images of apoptosis and engulfed apoptotic bodies. TUNEL positive structures were present in all corresponding regions. It seems therefore that apoptosis of epithelial cells of HRS and fibroblast-like cells of the periodontal ligament constitutes an integral part of the developmental process of the tissues of the periodontium. (C) 2000 Wiley-Liss, Inc.

Morphological aspects of rabbit masseter muscle after cervical sympathectomy

The objective of this paper was to study the effect of sympathetic innervation on morphological and histochemical aspects of skeletal muscle tissue. Rabbit masseter muscle was studied using histochemical and immunohistochemical methods for periods of up to 18 months post-sympathectomy. The morphological and enzymatic characteristics of control masseter muscles were similar on both the left and right sides. The main features were muscle fibres with a mosaic pattern and a predominance of type IIa fibres, followed by type I. Type IIb fibres showed very low frequency. Sympathectomized animals showed varying degrees of metabolic and morphological alterations, especially 18 months after sympathectomy. The first five groups showed a higher frequency of type I fibres, whilst the oldest group showed a higher frequency of type lib fibres. In the oldest group, a significant variation in fibre diameter was observed. Many fibres showed small diameter, atrophy, hypertrophy, splitting, and necrosis. Areas with fibrosis were observed. Thus cervical sympathectomy induced morphological alterations in the masseter muscles. These alterations were, in part, similar to both denervation and myopathy. These findings indicate that sympathetic innervation contributes to the maintenance of the morphological and metabolic features of masseter muscle fibres.

The ultrastructure of the guinea pig rete testis

The chambers of the rete testis (RT) of guinea pig are lined by a simple epithelium, whose cells are squamous, cubical and columnar in shape. The epithelial cells with distinct shapes were counted and the quantitative analysis of the number of these cells showed relative predominance of cubical cells. The ultrastructural observations showed predominance of membrane interdigitations among the epithelial cells. These cells present common cytoplasmic organelles. The Golgi complex polarity is typical with observation of electronlucent vesicles on the Golgi cis face closely related to rough endoplasmic reticulum (ER) lamellae, mitochondria and large number of polysomes on the Golgi trans face. These related structures present in Golgi area of RT cells suggest secretory activity which maybe occurs in the RT epithelium. Endocytotic process also occurs in the RT and this function probably concerns the uptake of substances and resorption of seminiferous fluid. Apical cilia present in RT epithelium cells are related with fluid transport and perhaps with chemoreception. Presence of spermatozoa portions enclosed into the cytoplasm of some epithelium cells has been refferred to as spermatophagy. The RT complex is mainly supported by loose connective tissue, with collagen fibres and some Leydig cells. Leydig cells are adjacent to the network channels of the septal part of the RT and apparently are able to secrete inside the RT lumen.

Ceramic Crucible Corrosion by Heavy Metal Oxide Glasses, Part II: Diffusion Study

Due to their low cost and high resistance to corrosion, ceramic crucibles can be used for the melting of PBG glasses (PbO-BiO 1.5GaO 1.5). These glasses present good window transmission from ultra-violet to infrared, making their use as optical fibres promising. However, their disadvantage is the high reactivity, leading to the corrosion of different crucibles, including gold and platinum ones. In this work, the corrosion of Al 2O 3, SnO 2 and ZrO 2 crucibles after melting at temperatures varying from 850 to 1000°C, was evaluated by Scanning Electronic Microscopy (SEM) in conjunction with microanalysis by EDS. The lead diffusion profile in the crucible material was obtained. Diffusion coefficients were calculated according to the Fick and Fisher theories. Results indicated that the different crucibles presented similar behaviour: in the region near the interface, diffusion occurs in the volumetric way and in regions away from the interface, diffusion occurs through grain boundary.

Características anatômicas de espinheira-santa (Maytenus ilicifolia Mart. ex Reissek e Maytenus aquifolia Mart.) e mata-olho (Sorocea bonplandii (Baill.) Burg. Lanj. & Boer.) para o controle de qualidade da matéria prima

Maytenus ilicifolia and Maytenus aquifolia (Celastraceae) both designated espinheira-santa have proven anti-ulcer activity. Morphologic similarities between leaves of espinheira-santa and mata-olho (Sorocea bonplandii), has motivated fakes in the market of phytotherapy. The present work consisted of the anatomical study, including stem and leaf, of the species M. ilicifolia, M. aquifolia and S. bomplandii. Samples of adult leaves and stem of plants located in the cities of Maringá and Marialva were collected. Both are located in the northwest region of Paraná State. The botanical material was prepared with using usual techniques of anatomy. The leaves of both Maytenus species presented great similarities, characterizing itself for the presence of epidermal cells with straight walls, biseriate palisade tissue, petiole vascular system represented by unique amphicribal bundle and sclereids, which were present in the stems of these two species. S. bomplandii leaves differed of Maytenus species for presenting epidermal cells with undulated walls, uniserite palisade tissue, petiole vascular system represented by many collateral bundles and gelatinous fibres. Non-glandular trichomes, glandular trichomes, and laticifer only occur in S. bomplandii.

Características estruturais da parede das artérias renal e femoral de coelho (Oryctolagus cuniculus)

In the renal and femoral arteries of rabbit was verified that both vessels had walls structured by myostromal components, despite of their different distributive of blood, being the renal artery a visceral blood vessel and the femoral artery a parietal vessel. This wall pattern in these vessels concerned to presence of connective stromal elements (collagen and elastic fibres and lamellae) and smooth muscle cells coexisting with some equilibrium in the wall structure of the renal and femoral arteries, mainly in the medial layer architecture. An intimal folding pattern was verified around the vascular lumen, possibly related to capacitance of the both arteries regarding to variability of pressure levels in cardiac cycle. Furthermore, myostromal relations of connective elements and smooth muscle cells verified in the medial layer and the network formed by connective elements in the adventitial layer of these arteries contributed to maintenance of wall viscoelasticity properties of the vessels.