The structure of the bilaminar zone in the human temporomandibular joint: a light and scanning electron microscopy study in young and elderly subjects.

The bilaminar zone (BZ) in the human temporomandibular joint (TMJ) of toothed adults (GI) and toothless, elderly humans (GII) were analysed using light and scanning electron microscopy (SEM). In both groups the BZ consists of an upper and a lower stratum of connective tissue separated by a vascularized middle region. The superior stratum contains bundles of collagen fibres disposed in different directions. The fibres are fairly thick and transversely oriented immediately posterior to the TMJ disc. The initial part of the inferior stratum contains curved bundles of collagen fibres oriented anterio-posteriorly. From the middle to the posterior part of the inferior stratum, the fibres are right-aligned in GI and clearly sinuous in nature in GII. In both groups, the middle and posterior portions of the middle region are distinguished by the presence of vessels and vascular spaces. Loosely arranged connective and adipose tissues are also evident. The vascular spaces are wider in GII than in GI. The predominance of type I collagen fibres is clear in all regions of the BZ in both groups. The elastic fibres lie parallel to the collagen fibres in both groups and they are thicker and more abundant in GI, apparently decreasing in GII.

The structure of the bilaminar zone in the human temporomandibular joint: a light and scanning electron microscopy study in young and elderly subjects / Estrutura da zona bilaminar na articulação temporomandibular humana: um estudo leve e microscopia eletrônica de varredura e assuntos antigos

The bilaminar zone (BZ) in the human temporomandibular joint (TMJ) of toothed adults (GI) and toothless, elderly humans (GII) were analysed using light and scanning electron microscopy (SEM). In both groups the BZ consists of an upper and a lower stratum of connective tissue separated by a vascularized middle region. The superior stratum contains bundles of collagem fibres disposed in diferent directions. The fibres are fairly thick and transversely oriented immediately posterior to the TMJ disc. The initial part of the inferior stratum contains curved bundles of collagem fibres oriented anterio-posteriorly. From the middle to the posterior part of the inferior stratum, the fibres are right-aligned in GI and clearly sinuous in nature in GII. In both groups, the middle and posterior portions of the middle region are distinguished by the presence of vessels and vascular spaces. Loosely arranged conective and adipose tissues are also evident. The vascular spaces are wider in GII than in GI. The predominance of type I collagen fibres is clear in all regions of the BZ in both groups. The elastic fibres lie parallel to the collagen fibres in both groups and they are thicker and more abundant in GI, apparently decreasing in GII

Xylanase production by Aspergillus awamori in solid-state fermentation and influence of different nitrogen sources.

The use of purified xylan as a substrate for bioconversion into xylanases increases the cost of enzyme production. Consequently, there have been attempts to develop a bioprocess to produce such enzymes using different lignocellulosic residues. Filamentous fungi have been widely used to produce hydrolytic enzymes for industrial applications, including xylanases, whose levels in fungi are generally much higher than those in yeast and bacteria. Considering the industrial importance of xylanases, the present study evaluated the use of milled sugarcane bagasse, without any pretreatment, as a carbon source. Also, the effect of different nitrogen sources and the C:N ratio on xylanase production by Aspergillus awamori were investigated, in experiments carried out in solid-state fermentation. High extracellular xylanolytic activity was observed on cultivation of A. awamori on milled sugarcane bagasse and organic nitrogen sources (45 IU/mL for endoxylanase and 3.5 IU/mL for beta-xylosidase). Endoxylanase and beta-xylosidase activities were higher when sodium nitrate was used as the nitrogen source, when compared with peptone, urea, and ammonium sulfate at the optimized C:N ratio of 10:1. The use of yeast extract as a supplement to the these nitrogen sources resulted in considerable improvement in the production of xylanases, showing the importance of this organic nitrogen source on A. awamori metabolism.

The arrangement of the trabecular bone in the vestibular surface of the human fetus mandible. A scanning electron microscopy study.

The characteristics of trabecular bone in human fetuses at seven to nine months of intra-uterine life were studied in the vestibular surface of the mental and body portions of the mandible. In the mental portion, many circular trabeculae joined by "bridges" were observed in the alveolar region (AR). In the 8-month old fetus are trabeculae with tortuous disposition in the medium region (MR). Oblique trabeculae with superior and inferior dispositions defining a triangular area (future mental fossae) are verified in 9-month old fetuses. Trabeculae circularly disposed and vascular foramina are present close to the apex of this area. In the basilar region (BR) some trabeculae obliquely oriented are observed disposed near to the mandibular symphysis. The longitudinal bundles of collagen fibers assume an antero-posterior direction. At 9-month age the vascular foramina range from 6 to 20 microns and the osteocyte lacunae ranging from 1 to 4 microns diameter, are present in mandibles from all ages examined. In the body portion the presence of circular trabeculae joined by "bridges" is the main characteristic of the AR. In the MR most of the trabeculae are circular and the longitudinal trabeculae of this region assume an antero-posterior direction. The laminar, antero-posterior and juxtaposed trabeculae lying parallel to mandible base are a characteristic of the BR. The bundles of collagen fibers exhibit the same pattern of the trabeculae. The vascular foramina of the BR are smaller than that of the precedent regions. In the body portion of the mandible from all ages examined the osteocyte lacunae range from 1 to 4 microns in diameter.

[Anatomical variations in the hypoglossal canal]. / Contribuição ao estudo das variações anatômicas do canal do hipoglosso.

In this paper, 492 human dried skulls grouped according to sex and race (White and no White) were examined and the presence of a double hypoglossal canal was observed in 97 skulls. The statistical analysis allowed us to conclude that no significative difference exists in race X canal type; sex X canal type; race X side and sex X side interations.