Mouth, histology

The tissue-level (histological) defense systems are composed primarily of the skin and the mucous membranes mucosa) that line the airways, mouth, and other portions of the gastrointestinal system. Healthy, intact skin is probably the most important barrier against chemical or biological insults. 

Cardiovascular Effects. Altered heart rate has been observed in humans following oral exposure to aluminum phosphide (Chopra et al. 1986 Khosla et al. 1988) however, the cardiotoxicity probably resulted from exposure to phosphine gas, rapidly released from aluminum phosphide in the mouth and stomach, rather than the aluminum. Oral exposure in rodents and dogs to other forms of aluminum has not been shown to affect heart weight or histology. 

Rats received intermittent exposure to the atmosphere in the furnace room of a phosphorus factory for 1-4 months (Ruzuddinov and Rys-Uly 1986). Histology of rats killed monthly revealed progressive morphological degeneration of the tongue and oral mucosa of the cheek, gum, and hard palate. It is likely that the effects of white phosphorus in the oral cavity are local rather than systemic resulting from direct contact of white phosphorus-containing atmosphere with tissues in the mouth. For this reason this study is also discussed in Section 2.2.2.2. 

In rats administered 0.075 mg/kg/day white phosphorus for an intermediate duration, no histological alterations were observed in the heart (Bio/dynamics 1991 IRDC 1985). In rats exposed for an intermediate duration to an unknown concentration of airborne white phosphorus from the furnace room of a phosphorus factory, an increase in permeability of capillary walls, lesions in the walls of blood vessels and evidence of impaired microcirculation were observed in the mouth (Ruzuddinov and Rys-Uly 1986). These effects probably resulted from the local action of white phosphorus on the oral cavity. 

Histological changes in the mucous membranes of the mouth and susceptibility to death among pregnant females during birth are also possible following longer term exposure. 

In tests designed to evaluate the primary irritation of mucous membranes, the tissues of choice (wherever possible) should be the specific mucosal to which the chemical is applied. Differences in histology, absorptive capacity, and pH ranges of the mouth, eye, genitourinary, and rectal mucosa are great enough that results obtained on one mucosa may not apply for the other. 

Basaloid squamous cell carcinoma (BSCC) is an uncommon, histologically distinct variant of SCC. In the upper aerodigestive tract, it occurs frequently in the base of the tongue, tonsils, hypopharynx, and larynx but has also been described in many other locations such as the palate, buccal mucosa, floor of mouth, nasopharynx, nasal cavity, and trachea. This is one of the subtypes of squamous carcinoma that can present with large neck node metastases and an unknown primary tumor. 

The two final sections are specifically concerned with aspects of Oral Biology. Section 7 on the Calcified Tissues, which includes chapters on calcium and phosphorus metabolism, biological apatite, mineralized tissues and the mineralization process, helps to bridge the gap between chemistry and dental histology. Finally in Section 8, Biology of the Mouth, consideration is given to biochemical aspects of saliva, the oral flora and the formation and properties of dental plaque. A chapter on plaque diseases completes this survey of dental biochemistry. 

Mouth - teeth Imaging and histology of bone and surroxmding mucosa Sweeks after cessation of chemotherapy containing bevacizumab showed avascular osteonecrosis of the mandible in a female patient with non-small cell lung cancer who experienced spontaneous teeth loss. Three months after withdrawal of bevacizumab, sequestration of the mandible with marked expansion of the mucosal vasculature began and spontaneous bone sequestration occurred a few months later followed by stable mucosal coverage [114 ]. 

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