Differential cell-specific location of Cav-1 and Ca2+-ATPase in terminal Schwann cells and mechanoreceptive Ruffini endings in the periodontal ligament of the rat incisor

Caveolae are involved in clathrin-independent endocytosis, transcytosis, signal transduction, and tumor suppression – all of which depend on their main constituent protein caveolin families. The periodontal Ruffini ending has been reported to develop a caveola-like structure on the cell membrane of both the axon terminals and Schwann sheaths, suggesting the existence of an axon–Schwann cell interaction in the periodontal Ruffini endings. However, little information is available concerning the functional significance of these caveolae. The present study was undertaken to examine the immunolocalization of caveolin-1, -3 (Cav-1, Cav-3) and Ca²⁺-ATPase in the periodontal Ruffini endings of the rat incisor. Decalcified sections of the upper jaws were processed for immunocytochemistry at the levels of light and electron microscopy. Some immunostained sections were treated with histochemistry for nonspecific cholinesterase (nChE) activity. Observations showed the periodontal Ruffini endings were immunopositive for Cav-1, but not Cav-3. Immunoreactive products for Cav-1 were confined to caveola-like structures in the cell membranes of the cytoplasmic extensions and cell bodies of the terminal Schwann cells associated with the periodontal Ruffini endings. However, the axonal membranes of the terminals did not express any Cav-1 immunoreaction. Double staining with Ca²⁺-ATPase and either protein gene product 9.5 (PGP 9.5) or S-100 protein disclosed the co-localization of immunoreactions in the axonal branches of the periodontal Ruffini endings, but not in the terminal Schwann cells. As Ca²⁺ plays an important role in mechanotransduction, these characteristic immunolocalizations show Cav-1/Ca²⁺-ATPase might be involved in the quick elimination of intracellular Ca²⁺ in mechanotransduction.     

Characteristics and sputum conversion of tuberculosis (TB) patients in Kalutara,Sri Lanka

Background

Tuberculosis (TB) is an infectious bacterial disease; remains as one of the important public health problem affecting every part of the world. Substantial number of TB cases are reported from Sri Lanka every year irrespective of its strong preventive health system. The aim of this analysis is to describe the characteristics of TB patients and to assess the factors associated with sputum conversion. This analysis was based on the data from the District Chest Clinic of Kalutara district, Sri Lanka.

Morphological analysis of cementoenamel junction in premolars of Sri Lankans

Anatomical Science International - Cementoenamel junction is an anatomical landmark which indicates the meeting point of enamel of the crown and the cementum of the root. It is an important...     

Distribution pattern of cholinesterase enzymes in human tooth germs

The two distinct molecular forms of cholinesterase (ChE) are acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Our previous studies have reported that ChE is involved in tooth development. However, further experiments are needed to understand the precise action of ChE in tooth development. This study aimed to localise types of ChE in human tooth germs, and identify their distribution pattern.ChE were localised in frozen sections of jaws which were prepared from dead fetuses, neonates and stillborns who were free from visible abnormalities by Karnovsky and Root method.AChE was identified in the inner and outer enamel epithelia including the cervical loop region, stratum intermedium and preameloblasts of tooth germs at bell stage. Secretory ameloblasts were free from staining. The bud and cap stages of permanent tooth germs showed AChE activity on the lingual aspect and top surface of the epithelial ingrowths, respectively. BuChE activity was localised in the degenerating dental lamina.Our study reported the first evidence of localisation of ChE in human tooth development and identified the possible molecular form of ChE in tooth germs as AChE. Also, our results have provided strong evidence to speculate the action of AChE is on the cells of enamel organ during tooth development.     

Involvement of GDNF and its receptors in the maturation of the periodontal Ruffini endings

Our recent study revealed an intense immunoreaction for GDNF and its receptors in the Ruffini endings, primary mechanoreceptors in the periodontal ligament, of young rats. However, no information is available for the expression of GDNF and its receptors during their development. The present study aimed to reveal postnatal changes in the immuno-expression of GDNF, GFRalpha1 and RET in the periodontal Ruffini endings of the rat incisors by double immunofluorescent staining. At postnatal day 3 (PO 3d), no structure with GDNF-, GFRalpha1-, or RET-immunoreaction existed in the periodontal ligament. The PGP 9.5-positive nerve fibers without GDNF- and RET-immunoreaction displayed a dendritic fashion at PO 1w, with a GFRalpha1-reaction found around these nerves. At PO 2w, GDNF-positive terminal Schwann cells occurred near the thick and dendritic axons, a part of which showed a RET-reaction, with no reactive cells near the thin nerves. The terminal Schwann cells became positive for GFRalpha1, but lacked RET-immunoreaction. At PO 3w, when the formation of the periodontal Ruffini endings had proceeded, GDNF-positive terminal Schwann cells began to increase in number. This stage-specific immuno-expression pattern suggests that GDNF is a key molecule for the maturation and maintenance of the periodontal Ruffini endings.     

Indoor air pollution and respiratory health of children in the developing world

Indoor air pollution (IAP) is a key contributor to the global burden of disease mainly in developing countries. The use of solid fuel for cooking and heating is the main source of IAP in developing countries, accounting for an estimated 3.5 million deaths and 4.5% of Disability-Adjusted Life Years in 2010. Other sources of IAP include indoor smoking, infiltration of pollutants from outdoor sources and substances emitted from an array of human utilities and biological materials. Children are among the most vulnerable groups for adverse effects of IAP. The respiratory system is a primary target of air pollutants resulting in a wide range of acute and chronic effects. The spectrum of respiratory adverse effects ranges from mild subclinical changes and mild symptoms to life threatening conditions and even death. However, IAP is a modifiable risk factor having potential mitigating interventions. Possible interventions range from simple behavior change to structural changes and from shifting of unclean cooking fuel to clean cooking fuel. Shifting from use of solid fuel to clean fuel invariably reduces household air pollution in developing countries, but such a change is challenging. This review aims to summarize the available information on IAP exposure during childhood and its effects on respiratory health in developing countries. It specifically discusses the common sources of IAP, susceptibility of children to air pollution, mechanisms of action, common respiratory conditions, preventive and mitigating strategies.     

Regional distribution of interglobular dentine in human teeth

Interglobular dentine (IGD) is an area of poorly mineralized dentine matrix. It has been reported that there is an association between the retraction of odontoblast processes (OP) and the formation of IGD. A variation of the extent of OP has been described depending on the region of the tooth and age. This study aimed to find out the regional distribution of IGD in human teeth to observe any association between the extent of OP and the pattern of distribution of IGD.Ground sections were prepared from 52 extracted permanent teeth and the presence of IGD was observed in different regions of the crown and the root.The highest occurrence of IGD was found in the cervical and middle thirds followed by intercuspal, and coronal third in the crown. Statistical analysis of data depicted that the occurrence of IGD differed according to the region of the tooth. In roots, the highest occurrence of IGD was seen in the cervical third followed by the middle third.Previous reports have shown that OP extend up to the dentine–enamel junction in the coronal region and to the inner one-third of the cervical region. The varied pattern of distribution of IGD in the crown and root observed in our results corresponds to the above findings. Therefore, it is reasonable to surmise that there is an association between the distribution of IGD and the extent of OP. This allows us to confer that IGD tends to form in areas where OP do not extend to the dentine–enamel junction.     

A profile of biomass stove use in Sri Lanka

A large body of evidence has confirmed that the indoor air pollution (IAP) from biomass fuel use is a major cause of premature deaths, and acute and chronic diseases. Over 78% of Sri Lankans use biomass fuel for cooking, the major source of IAP in developing countries. We conducted a review of the available literature and data sources to profile biomass fuel use in Sri Lanka. We also produced two maps (population density and biomass use; and cooking fuel sources by district) to illustrate the problem in a geographical context. The biomass use in Sri Lanka is limited to wood while coal, charcoal, and cow dung are not used. Government data sources indicate poor residents in rural areas are more likely to use biomass fuel. Respiratory diseases, which may have been caused by cooking emissions, are one of the leading causes of hospitalizations and death. The World Health Organization estimated that the number of deaths attributable to IAP in Sri Lanka in 2004 was 4300. Small scale studies have been conducted in-country in an attempt to associate biomass fuel use with cataracts, low birth weight, respiratory diseases and lung cancer. However, the IAP issue has not been broadly researched and is not prominent in Sri Lankan public health policies and programs to date. Our profile of Sri Lanka calls for further analytical studies and new innovative initiatives to inform public health policy, advocacy and program interventions to address the IAP problem of Sri Lanka.