Long-term Effectiveness of Integrated Caries Preventive Programs in Thailand Among Preschool Children Using a System Dynamics Model.

OBJECTIVE: To compare the effect of three caries preventive interventions provided by Thailand's Ministry of Public Health (MOPH): supervised toothbrushing (STB), fluoride varnish (FV), and combined STB+FV from 0 to 5 years old to the base case using the System Dynamics Model (SDM). METHODS: The SDM was developed to compare the intervention scenarios: STB, FV, and combined STB+FV with the base case scenario. Meta-analyses determined the effective rates of the interventions included in the model. RESULTS: The model indicated that the population with no caries in deciduous teeth increased by 7.5%, 5.7%, and 4.2% at three years of age, and 12.8%, 9.9%, and 5.9% at five years of age, under STB+FV, STB, and FV respectively when compared to the base case. At three years old, the population with untreated caries in deciduous teeth decreased by 12.9% in STB+FV, 9.8% in STB, and 7.3% in FV, and by 10.9% in STB+FV, 8.5% in STB, and 4.9% in FV, at five years old. The increase in the population without caries is considered clinically significant compared to baseline. CONCLUSION: The model determined that an effective combination of STB and FV should be administered between 0 and 5 years of age to reduce caries in the primary dentition. The SDM could be applied as a "what-if" analysis in order to determine the most beneficial intervention or policy by comparing them.

Amphipithecine primates are stem anthropoids: cranial and postcranial evidence.

Since their discovery in 1927, the phylogenetic status of the Myanmar amphipithecines has been highly debated. These fossil primates are recognized either as anthropoids or as adapiform strepsirrhines. This uncertainty was largely the consequence of a limited fossil record consisting mostly of jaw fragments but lacking the critical cranial elements that might resolve this debate. We report here cranial remains associated with an ulna from a single individual pertaining to the amphipithecine Ganlea megacanina. In addition to anthropoid-like dentognathic characters, Ganlea displays several ulna and skull features that testify to its anthropoid affinities (e.g. short subvertically oriented lacrimal duct, lacrimal foramen and bone inside the orbit, maxillary contribution to the lower orbital rim, fused metopic suture). By contrast to crown anthropoids, however, Ganlea lacks postorbital closure, confirming that postorbital closure appeared later than many anthropoid dentognathic characters and evolved convergently in extant tarsiers and anthropoids. Thus, amphipithecines must now be recognized as stem anthropoids offering a unique window on the early evolution of cranial and skeletal features in anthropoids, and reinforcing the hypothesis of an origin and early diversification of anthropoids in Asia.

Prevalence and causes of visual impairment in rural myanmar: the Meiktila Eye Study.

OBJECTIVE: To determine the prevalence and causes of visual impairment in the Meiktila district of central, rural Myanmar. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Random, stratified, cluster sampling of the inhabitants 40 years of age and older from villages in the Meiktila district was performed; 2481 eligible participants were identified and 2076 participated in the study. METHODS: The ophthalmic examination included presenting and pinhole Snellen visual acuity with an illiterate E chart, slit-lamp examination of the anterior segment, and dilated stereoscopic fundus examination. The principal cause of visual impairment was recorded. MAIN OUTCOME MEASURES: Visual impairment and blindness were defined by both presenting and corrected visual acuity according to World Health Organization criteria: better eye < 6/18 and < 3/60, respectively. RESULTS: Comprehensive examinations, including Snellen visual acuity, were performed on 2073 participants (83.6%) The prevalence estimate of presenting visual impairment was 40.4% (95% confidence interval [CI], 36.1-44.7) and of presenting blindness was 8.1% (95% CI, 6.5-9.9). After pinhole correction, the corresponding prevalences were 26.8% (95% CI, 23.5-30.1) and 5.3% (95% CI, 4.0-6.6). Cataract, uncorrected refractive error, and glaucoma were the most common causes of visual impairment. CONCLUSIONS: Visual impairment and blindness remain major public health problems in rural Myanmar. Specific programs directed toward reducing the cataract burden need to be implemented.

Apoptosis in substantia nigra following developmental hypoxic-ischemic injury.

We have previously observed that either hypoxic-ischemic or excitotoxic striatal injury during development is associated with a reduction in the adult number of dopaminergic neurons in the substantia nigra. This decrease occurs in the presence of preserved striatal dopaminergic markers and in the absence of direct nigral injury. We have also observed that natural cell death, with the morphology of apoptosis, occurs in the substantia nigra, and that there is an induced apoptotic cell death event following early striatal excitotoxic injury. We now report that forebrain hypoxic-ischemic injury is also associated with an induced cell death event in the substantia nigra, with both morphological and histochemical features of apoptosis. Induced apoptotic cell death occurs in immunohistochemically defined dopaminergic neurons. While the mechanisms for this induced cell death are not yet known, in the case of the pars compacta it may be related to the loss of normal striatal target-derived developmental support. Since dopaminergic neurons are postmitotic at the time of the injury, we conclude that this induced cell death is responsible for the diminished adult number of dopaminergic neurons. We also conclude that hypoxic-ischemic injury to the developing brain in general causes not only direct, necrotic injury to vulnerable regions, but also induced apoptotic death at remote sites. The significance of this finding is that apoptosis is a distinct death mechanism, with unique regulatory pathways, which can potentially be modified by approaches different from those which might influence cell death in regions of direct injury. In view of the present finding that apoptosis can occur in the setting of hypoxic-ischemic injury, and our previous work demonstrating its occurrence following excitotoxic injury, it seems likely that it may occur following other forms of injury to the immature brain in which excitotoxic injury plays a role, such as seizures, head trauma and hypoglycemia.

Upregulation of cytosolic branched chain aminotransferase in substantia nigra following developmental striatal target injury.

We have previously shown that apoptotic cell death can be induced in substantia nigra (SN) by developmental striatal target lesion. In this model, only a portion of nigral neurons dies, so it provides a paradigm to examine not only the molecular basis of cell death, but also the cellular responses of adjacent neurons which survive. Using a differential display approach, we have found that cytosolic branched chain aminotransferase (BCATc) mRNA is upregulated in SN in this model. This upregulation is associated with an increased number of BCATc-positive neuronal profiles, demonstrated by immunostaining. BCATc-positive neurons show normal morphology and rarely contain apoptotic chromatin. We conclude that BCATc is upregulated in neurons, which are likely to survive, and plays a role in either maintenance of viability or restoration of normal function.

Augmented pharmacologic stimulation of striatal acetylcholine release following developmental hypoxic-ischemic injury.

We have previously shown that developmental hypoxic-ischemic injury in a unilateral rodent model leads to an increase in both morphologic and biochemical indices of striatal cholinergic neurons. To investigate the functional significance these changes, we have used the in vivo microdialysis technique to examine the regulation of striatal acetylcholine release in awake, adult rats following postnatal hypoxic-ischemic injury. We have found that injury does not alter basal release or acetylcholine, but it results in a marked augmentation in the increase of acetylcholine release normally observed after infusion of atropine or pirenzepine.

The time course of developmental cell death in phenotypically defined dopaminergic neurons of the substantia nigra.

We have previously shown that apoptotic natural cell death occurs within the substantia nigra (SN) pars compacta of the rat postnatally. However, the occurrence of natural cell death in phenotypically defined dopaminergic neurons has not previously been identified, nor has its time course been defined in pre- or postnatal development. We therefore examined the SN at intervals from E19 to P28 using immunostaining for tyrosine hydroxylase with a Nissl counterstain to identify intranuclear apoptotic chromatin clumps. We have found that natural cell death in dopaminergic neurons is biphasic. An initial, broad peak begins at E20, reaches maximum at P2, and abates by P8. A second peak occurs at P14. We conclude that most of the natural cell death in this neuronal population occurs in the early postnatal period.

Synuclein expression is decreased in rat substantia nigra following induction of apoptosis by intrastriatal 6-hydroxydopamine.

We have previously shown that synuclein is upregulated in the substantia nigra following developmental lesion of the target striatum. In this model, synuclein is preferentially expressed in normal-appearing neurons, rather than those which undergo apoptosis. It has been proposed, however, that synuclein may mediate apoptosis in other contexts, such as that induced by neurotoxins. To examine this possibility, we have studied a model in which apoptosis is induced in dopamine neurons by intrastriatal injection of 6-hydroxydopamine. In this model synuclein mRNA and protein expression are not upregulated at any time point, but instead diminish as dopamine neurons die. We observe a complete dissociation between apoptotic morphology and synuclein protein expression. We conclude that synuclein is unlikely to play a direct role in apoptotic death in dopamine neurons and is more likely, in the target injury model, to play a role in protection or restoration of neurons which survive.

Animal models of induced apoptotic death in the substantia nigra.

Apoptosis is a form of cell death in which genetically regulated programs intrinsic to the cell bring about its own demise. In recent years, there has been a tremendous growth of interest in apoptosis as a mechanism of disease in a wide range of human disorders including the neurodegenerative diseases, such as Parkinson's disease (PD) (1). This growth of interest has spawned an extraordinary number of recent discoveries about the molecular basis of apoptosis. It is important to emphasize, however, that much of this new knowledge has been attained in the study of relatively simple systems, such as invertebrate models or mammalian nonneural cell culture systems. Less is known about these mechanisms in neural cells, and much of what is known is based on studies of peripheral neural cells (such as sympathetic ganglia and PC 12 cells) in tissue culture. Much less is known about central neurons; in particular, we know little about the regulation of apoptotic death in central neurons in living animals. It is especially important to try to identify the mechanisms of cell death in central neurons of known phenotype, particularly those implicated in human neurodegenerative disease, such as the dopamine neurons in PD. The purpose of the models we have developed of induced apoptosis in dopamine neurons of the substantia nigra (SN) is to try to translate what is being learned about the molecular mechanisms of apoptosis in simpler systems to these neurons.

Apoptotic morphology in phenotypically defined dopaminergic neurons of the substantia nigra.

In the preceding chapter we described three paradigms by which we have studied programmed cell death in the substantia nigra (SN) of living animals: natural cell death and death induced either by developmental injury to the target striatum or by dopamine terminal destruction with the neurotoxin 6-hydroxydopamine (6-OHDA). In each of these paradigms, in order to relate experimental investigations specifically to dopamine neurons, the dopaminergic phenotype must be identified in conjunction with the demonstration of apoptotic morphology. This identification is essential, because apoptosis has been recognized in diverse neuronal populations and in glia (1).

Protocol of a prospective cohort study of the effect of different methods of drainage of neuropathic bladder on occurrence of symptomatic urinary infection, and adverse events related to the urinary drainage system in spinal cord injury patients.

BACKGROUND: To present a protocol of a prospective, cohort study in which four groups of spinal cord injury (SCI) patients will participate. (Patients with indwelling urethral catheter; patients who perform intermittent catheterisation without wearing a penile sheath; patients who perform intermittent catheterisation and wear penile sheath as well; and patients with penile sheath drainage). OBJECTIVES: (1) What is the incidence of symptomatic urinary infection in men with spinal cord injury who use different types of bladder drainage? (2) Which are predisposing factors for the occurrence of symptomatic urinary infection in men with spinal cord injury who practise different methods of bladder drainage? (3) What is the incidence of catheter and urinary drainage system-related adverse events in the four groups of SCI patients? PATIENTS: The criteria for inclusion are as follow: (1) Male patients with neuropathic bladder due to spinal cord injury, who are registered with the Regional Spinal Injuries Centre, Southport, England. (2) Age: 18 years or above. (3) Patients who are willing to give informed consent for participation in the study. (4) Patients willing to be contacted every two weeks by a staff of the spinal unit for 36 months. (5) Patients who are willing to maintain an accurate record of adverse events related to urinary catheter and urinary drainage system and predisposing factors for the occurrence of symptomatic urinary infection. (6) Patients, who are stabilised in a particular method of bladder drainage, and therefore, unlikely to make a permanent change in the method of bladder drainage (e.g. from penile sheath drainage to the use of long-term indwelling catheter) during a foreseeable future. METHODS: The participants will be observed for a period of 36 months. A staff of the spinal injuries unit will contact the participants by telephone every two weeks on a mutually agreed day and time. The information obtained during this standardised telephonic interview conducted once in two weeks will be entered in a database. When a participant develops symptom(s) suggestive of urinary infection, he will undergo urine and blood tests, and imaging studies of the urinary tract. CONCLUSION: This study will provide information regarding the occurrence of symptomatic urinary infection, predisposing factors for development of urinary infection, and adverse events related to urinary catheter and urinary drainage system in SCI patients using different methods of bladder drainage.

Field trial of efficacy of local compression immobilization first-aid technique in Russell's viper (Daboia russelii siamensis) bite patients.

A field trial of efficacy of local compression immobilization first-aid technique in 42 Russell's viper bite cases was studied and only 19 were envenomed. Proper immobilization was carried out in 3/13 immobilized cases. The average time of application of the pad was 1.12 hours (range 5 minutes to 7 hours) and the total duration of the pad application was 3 hours 40 minutes (range 30 minutes to 9 hours). Venom levels measured at the hospital before and at 15 and 30 minutes after release of the pad (n=10) showed a rise of 5 to 30 ng/ml of venom following release. Movement of venom antigen was found to be retarded in all cases (n=9) whose venom levels were measured at 15 and 30 minutes with the pad in place. Sixteen out of 19 cases had systemic envenoming, indicating that pad or immobilization alone is not effective in delaying spread of venom. The incidence of local necrosis 3/42 (8%) following use of the pad was comparable to that of the systemic cases without the pad. No ill effects were observed following its application for as long as 9 hours. Local blackening seen in 4/36 (10%) cases was likely to be result of a local venom effect.

The use of personal protective measures in control of malaria in a defined community.

Malaria is one of the main health problems in the non-immune immigrant workers and army personnel of the malaria endemic areas in Myanmar. Due to changes in the vector bionomics and multiresistant strains of P. falciparum, chemoprophylaxis alone is not an effective means of control of malaria in them. So it is envisaged that the combined used of personal protective measures (deltamethrin impregnated bed-nets, scalves and hand-bands) and the chemoprophylaxis will be an effective means of control of malaria in the define group of people. The study also intended to find out the side effects of the deltamethrin and feasibility and acceptability of methods by the users. The study was conducted in Theini Township, Northern Shan State, from March to November 1993. The study population consisted of all ages of both sexes 554 and 440 persons in the test and control groups respectively. At the initial phase of the study, malaria infected persons from both the groups were treated. The experimental group received personal protective measures with impregnation of bed-nets using 25 mg ai/m2 of deltamethrin at 4 monthly intervals and the scarves and hand-bands at twice the concentration of the insecticides at monthly intervals. Chemoprophylaxis was given to both the groups at weekly intervals using age adjusted dosage of Pyrixine tablet (sulfadoxine-pyrimethamine). The parasitological, entomological, and epidemiological indices were collected at two month intervals in both the groups. The study clearly showed the impact of personal protective measures and chemoprophylaxis on malaria infection in the studied subjects. During the study period, the out patient malaria cases of the test group was 6% to 11.2% and that of the control group was 12% to 21.6% in Theini Hospital. The reinfection rate of the test group (0.9 to 4.7%) was also significantly lower than the control group (6.1 to 14.3%) from July to November. Acceptance of the treated bed-nets, scarves and hand-bands was high and good compliance was found in the follow up. The results of the study clearly showed that malaria can be controlled effectively in the defined group of persons for a malaria transmission season by using chemoprophylaxis and personal protective measures.

Factors influencing the seasonal abundance of Aedes (Stegomyia) aegypti and the control strategy of dengue and dengue haemorrhagic fever in Thanlyin Township, Yangon City, Myanmar.

From June 2006 to May 2007, mosquito surveys were conducted in Thanlyin Township, Yangon City, Myanmar, to determine factors influencing the abundance of Aedes aegypti (Stegomyia aegypti) during the rainy season. Both the biological and environmental factors were included in this study. Increase in the hatchability of egg, larval survival rate, the shortened larval life-span and increased pupation rates supplemented by rainfall (i.e. continuous flooding of the containers, stimulate the continuous hatching of eggs) were observed for correlation with the increase in population density of Ae. aegypti during the rainy season in the study area. Control strategy of Ae. aegypti to analyze the infestation in the community (study area) with larval Ae. aegypti, integrated management measures including health education, attitudes and practices regarding dengue and dengue haemorrhagic fever, transmission of the disease and possible preventive measures, reduction of breeding sites and testing the efficacy of Bacillus thuringiensis israelensis (B.t.i.) with respect to the reduction level of Ae. aegypti larvae in breeding sources, were taken into consideration.