Human Dentition and Notation
P. Sema Aka, Murat Yagan, Nergis Canturk, Rukiye Dagalp in Primary Tooth Development in Infancy, 2016
Human dentition exists on both maxillary (upper jaw) and mandibular (lower jaw) bones, which develops in two stages: primary dentition (deciduous, transitory, milk, lacteal, baby dentition) including 20 teeth and permanent dentition ( secondary, successional dentition) including 32 teeth. These teeth are denominated as: central incisor (di1), lateral incisor (di2), canine (dc), first molar (dm1), second molar (dm2) for primary (deciduous) dentition and central incisor (I1), lateral incisor (I2), canine (C), first premolar (P1), second premolar (P2), first molar (M1), second molar (M2), and third molar (M3) for permanent dentition.1,2 The primary dentition com prises two incisors, one canine and two molar teeth, whereas permanent dentition has two incisors, one canine and three molar teeth and additionally two premolar teeth in each quadrant. There are four quadrants, each covering five teeth for primary dentition and eight teeth for permanent dentition; these are placed in an imaginary plus sign that separates the right and left teeth with a vertical midsagittal line, and upper and lower teeth by the horizontal occlusal line. The incisor tooth that is closest to the midline is called the central incisor, the teeth distal to the central incisors are the lateral and canine incisors. Similarly, both premolar and molar teeth are labeled according to the midsagittal guideline. The clos est teeth to this plane are labeled and ordered first, the teeth distal to the first are labeled second and the furthest teeth to the midsagittal plane are labeled third molars.3
Targeting the intestinal lymphatic system: a versatile path for enhanced oral bioavailability of drugs
Published in Expert Opinion on Drug Delivery, 2018
Renuka Suresh Managuli, Sushil Yadaorao Raut, Meka Sreenivasa Reddy, Srinivas Mutalik
Introduction: The major challenge of first pass metabolism in oral drug delivery can be surmounted by directing delivery toward intestinal lymphatic system (ILS). ILS circumvents the liver and transports drug directly into systemic circulation via thoracic duct. Lipid and polymeric nanoparticles are transported into ILS through lacteal and Peyer’s patches. Moreover, surface modification of nanoparticles with ligand which is specific for Peyer’s patches enhances the uptake of drugs into ILS. Bioavailability enhancement by lymphatic uptake is an advantageous approach adopted by scientists today. Therefore, it is important to understand clear insight of ILS in targeted drug delivery and challenges involved in it. Areas covered: Current review includes an overview of ILS, factors governing lymphatic transport of nanoparticles and absorption mechanism of lipid and polymeric nanoparticles into ILS. Various ligands used to target Peyer’s patch and their conjugation strategies to nanoparticles are explained in detail. In vitro and in vivo models used to assess intestinal lymphatic transport of molecules are discussed further. Expert opinion: Although ILS offers a versatile pathway for nanotechnology based targeted drug delivery, extensive investigations on validation of the lymphatic transport models and on the strategies for gastric protection of targeted nanocarriers have to be perceived in for excellent performance of ILS in oral drug delivery.
The discovery of the lymphatic system in the seventeenth century. Part IV: the controversy
Published in Acta Chirurgica Belgica, 2017
Raphael Suy, Sarah Thomis, Inge Fourneau
A controversy over the transport of chyle and lymph started a few weeks after the publication of Pecquet’s Experimenta Nova Anatomica. There are records of nearly seventy people who had an active interest in this matter. Three issues were discussed: the purpose of the liver and especially its haematopoietic function, the capacity of the thoracic duct to transport all chyle, and the purpose of the lymph vessels. The controversy over the use of the lacteals and the lymph vessels subsided about 20 years after the first publication of the new theories. In this contribution, we focused on the ideas of William Harvey, since his ideas were close to the real configuration of the lymphatic system, and on the peculiar anatomical set-up of Louis De Bils (ca 1624-1669), an obscure French-Flemish non-professional anatomist, who was the initiator of a heated controversy in the Netherlands with his original ideas.
The discovery of the lymphatic system in the seventeenth century. Part II: the discovery of Chyle vessels
Published in Acta Chirurgica Belgica, 2016
Raphael Suy, Sarah Thomis, Inge Fourneau
In the seventeenth century, opportunities to discover chyle came about through the revival of vivisection. Gaspare Aselli discovered chyle vessels in a living well-fed dog in 1622. He introduced the term 'lacteals' or milky veins. According to Aselli, the lacteals passed through a mesenteric gland which he called 'pancreas'. The 1627 edition of Aselli's booklet was the start of a 'lymphomania', which led to the dissection and vivisection of hundreds of animals, with the University of Leiden being the clear leader in this field. The prominent researchers in Leiden were Jacobus Sylvius and Johannes Walaeus, who performed diverse experiments to support Harvey's theories on systemic circulation, and to find out the correct anatomy and physiology of lacteals and mesenteric glands. Another centre of excellence was Padua, where Veslingius and Wirsüng introduced the idea of the prominent role of the 'real pancreas', and its duct in the transformation of digested food into clear chyle. The idea of the transport of chyle to the liver was an additional support for Galen's theories regarding the function of the liver. Nevertheless, as time went on, there were fewer and fewer believers in Galenic doctrine.