Effect of electric potential and current on mandibular linear measurements in cone beam CT.

OBJECTIVES: The purpose of this study was to compare mandibular linear distances measured from cone beam CT (CBCT) images produced by different radiographic parameter settings (peak kilovoltage and milliampere value). METHODS: 20 cadaver hemimandibles with edentulous ridges posterior to the mental foramen were embedded in clear resin blocks and scanned by a CBCT machine (CB MercuRay(TM); Hitachi Medico Technology Corp., Chiba-ken, Japan). The radiographic parameters comprised four peak kilovoltage settings (60 kVp, 80 kVp, 100 kVp and 120 kVp) and two milliampere settings (10 mA and 15 mA). A 102.4 mm field of view was chosen. Each hemimandible was scanned 8 times with 8 different parameter combinations resulting in 160 CBCT data sets. On the cross-sectional images, six linear distances were measured. To assess the intraobserver variation, the 160 data sets were remeasured after 2 weeks. The measurement precision was calculated using Dahlberg's formula. With the same peak kilovoltage, the measurements yielded by different milliampere values were compared using the paired t-test. With the same milliampere value, the measurements yielded by different peak kilovoltage were compared using analysis of variance. A significant difference was considered when p < 0.05. RESULTS: Measurement precision varied from 0.03 mm to 0.28 mm. No significant differences in the distances were found among the different radiographic parameter combinations. CONCLUSIONS: Based upon the specific machine in the present study, low peak kilovoltage and milliampere value might be used for linear measurements in the posterior mandible.

Anatomical considerations of the deep peroneal nerve for biopsy of the proximal fibula in Thais.

The present research aims to study the anatomical relationship between the deep peroneal nerve and the neighboring structures in the proximal fibula of Thais, with special regard to define the boundaries of a "safe" area when performing a biopsy of the proximal fibula. The proximal parts of 118 legs of 59 formalin-embalmed adult cadavers (31 males, 28 females) were investigated. The distance from the apex of the fibular head to the point of origin of the deep peroneal nerve, the distance from the most lateral prominence of the fibular head to the anterior intermuscular septum, and the angle between the deep peroneal nerve and the fibula axis were measured. The results showed that the mean distances from the apex of the fibular head to the point of origin of the deep peroneal nerve was 28.4 +/- 4.8 mm and from the most lateral prominence of the fibular head to the anterior intermuscular septum was 14.9 +/- 2.0 mm. The mean angle between the deep peroneal nerve and the fibular axis was 28.1 degrees +/- 7.2 degrees . In conclusion, these findings suggest that a "safe" area for bone biopsy in the proximal fibula of Thais is palpable anterior to the fibular head and downward laterally, not lower than 28 mm or 8% of the fibular length and from the most lateral prominence transverse medially not further than 14 mm. The inferior boundary of this area is an oblique line of the deep peroneal nerve about 28 degrees from the fibular axis.

Prevalence and clinical characteristics of oral tori in 1,520 Chulalongkorn University Dental School patients.

The objectives of this study were to determine the prevalence, size, shape and location of the oral tori in 1,520 Thai dental patients and to investigate the relationship between the findings with age and gender. The prevalence rates were 60.5% for torus palatinus (TP) and 32.2% for torus mandibularis (TM). The concurrence of TP and TM was noted in 23.2% subjects. The peak incidence of TP and TM was in the third decade of life. TP affected more women than men (70.5 vs. 48.8%, P < 0.001). Most TP were found in spindle shape (56%), small size (52.1%) and located at premolar region (47.4%). The occurrence of TM was higher in men than in women (36.3 vs. 28.6%, P = 0.002). TM was found most common in small size (65.6%), as bilateral multiple nodes (59.3%) and usually located at the premolars (89.2%). The age and gender-related differences with the size of tori were noted. Subjects who had larger TP or TM were older than those who had smaller TP or TM (P < 0.001 and P = 0.001, respectively). Women were more likely to have larger TP whereas men tended to have larger TM. This study showed high prevalence rates of TP and TM in dental patients and the occurrences were related to gender.

Supraorbital Notch/Foramen, Infraorbital Foramen and Mental Foramen in Thais: anthropometric measurements and surgical relevance.

OBJECTIVE: To determine the morphology and the locations of the SupraOrbital Notch/Foramen (SON/F), InfraOrbital Foramen (IOF), and Mental Foramen (MF) relative to frequently encountered surgical landmarks. MATERIAL AND METHOD: One hundred and six Thai adult skulls were investigated. RESULTS: Mean horizontal widths of SON, SOF, IOF and MF were 4.31 +/- 1.61 mm, 2.81 +/- 0.62 mm, 3.35 +/- 0.62 mm and 2.80 +/- 0.70 mm, respectively. The SON/F was situated 25.14 +/- 4.29 mm lateral to the nasal midline, 26.57 +/- 3.92 mm medial to the temporal crest of the frontal bone and 3.15 +/- 1.29 mm superior to the supraorbital rim. The IOF was 28.43 +/- 2.29 mm lateral to the maxillary midline, 9.23 +/- 2.03 mm below the infraorbital rim and 2.15 +/- 1.67 mm medial to the zygomaticomaxillary suture. Mean vertical distances from the IOF to the SOF and to occlusal plane of the upper teeth were 44.95 +/- 2.96 mm and 42.52 +/- 3.89 mm, respectively. The IOF was frequently found in the same vertical line with the second upper premolar and its usual direction of opening pointed downward medially. The MF was a mean of 28.52 +/- 2.15 mm lateral to the symphysis menti and most commonly observed in line with the second lower premolar. Its usual direction of opening was in a posterosuperior direction. CONCLUSION: The results of the present study may assist surgeons to localize important maxillofacial neurovascular bundles passing through these foramina in facilitating surgical, local anesthetic and other invasive procedures.

Mental foramen in Thais: an anatomical variation related to gender and side.

Sixty-nine adult mandibles (45 male, 24 female) of Thai dry skulls were assessed to determine the size, the orientation and the location of the mental foramen (MF) related to gender and side. The results showed that the usual direction of exit of the MF was in a posterosuperior direction. The most common location of the MF was bilaterally symmetrical and located on the same vertical line with the long axis of the lower second premolar. The mean distances from the MF to the symphysis menti (A), to the posterior border of the mandibular ramus (P), to the lower border of the mandible (mb) and to the buccal cusp tip of the second premolar (cm) were 28.83, 68.85, 14.88 and 24.27 mm, respectively. The mean distances from the alveolar bone crest across the MF to the lower border of the mandible (ab) was 29.97 mm. The mean distance from the buccal cusp tip of the second premolar through the long axis of the clinical crown to the lower border of the mandible (cb) was 39.18 mm. No measurements varied according to the sides (P > 0.05). In contrast, gender differences were significant in all measurements with the longer distances in males (P < 0.05). The mean ratios of A/(A + P), mb/ab and cm/cb in all subjects were 0.30, 0.50 and 0.62, respectively. The values of the three ratios were nearly equal in males and females. Our results may assist surgeons to localize important maxillofacial neurovascular bundles passing through the MF in avoiding complication from local anesthetic, surgical and other invasive procedures.

Anatomy of greater palatine foramen and canal and pterygopalatine fossa in Thais: considerations for maxillary nerve block.

This study aims to investigate the anatomy of the greater palatine foramen (GPF), greater palatine canal (GPC) and pterygopalatine fossa (PPF) with special reference to the blockage of the maxillary nerve. A correlation between the length of GPC and PPF and the heights of the orbit and the maxilla was also studied using simple linear regression analysis. The morphology of the GPF, GPC and PPF as well as heights of the orbit and the maxilla were assessed in 105 Thai skulls. The thickness of the mucosa over the GPF was also measured from the dissection of 55 cadavers. The results showed that most GPF appeared as an oval foramen located at the palatal aspect of the upper third molar. The GPF was 16.2+/-1.3 mm lateral to the median sagittal plane of the hard palate, 2.1+/-1.3 mm anterior to the posterior border of the hard palate and 5.1+/-1.3 mm from the greatest concavity of the distolateral margin of the hard palate. The mean length of GPC and PPF was 29.7+/-4.2 mm. The mean angles of the GPC in relation to the hard palate and the vertical plane were 57.9+/-5.8 degrees and 6.7+/-5.2 degrees , respectively. In attempting to insert a needle to reach the foramen rotundum through the GPF, 31.7% passed into the orbit while 8.7% passed into the brain. The mean thickness of the mucosa over GPF was 6.7+/-2.3 mm. Two models for estimating the depth of needle injection in maxillary nerve block have been developed as follows: Length of GPC and PPF=19.038+0.314 (orbital height) and length of GPC and PPF=21.204+0.187 (maxillary height). The calculated length combined with the mucosal thickness was the estimated depth of needle injection. In conclusion, our results concerning the GPF, GPC and PPF will provide the useful reference for clinicians to anesthetize the maxillary nerve with a greater degree of success.

Clinical anatomy of the posterior maxilla pertaining to Le Fort I osteotomy in Thais.

This article studies the anatomy of the posterior maxilla pertaining to bone-cut design of Le Fort I osteotomy to avoid the injury to the descending palatine artery in Thais. Fifty-five skulls (38 males, 17 females) were assessed for the anatomical landmarks by a combination of direct inspection, computerized imaging, and computed tomography scan analysis. The results showed that 27.28% of the pterygomaxillary junction (PMJ) became synostosis. The mean heights of the PMJ, posterior maxilla, and maxillary tuberosity were 15.14 +/- 2.46 mm, 22.51 +/- 3.50 mm, and 7.45 +/- 2.76 mm, respectively. The mean length of the medial sinus wall measuring from the piriform rim to the descending palatine canal at the Le Fort I level was 34.40 +/- 2.96 mm. The mean widths of the posterior incision of Le Fort I osteotomy at the maxillary tuberosity and PMJ were 20.38 +/- 2.82 mm and 11.60 +/- 1.57 mm. The mean length of the posterior maxilla was 27.18 +/- 2.49 mm. Distances from the greater palatine foramen to the maxillary tuberosity incision and PMJ incision were 1.76 +/- 1.12 mm and 3.59 +/- 1.40 mm. The mean angle between the descending palatine canal and the hard palate was 57.33 +/- 4.54 degrees . There were no significant differences in any measurements between sides and genders, except the pterygoid process width and posterior maxilla length of males were longer than those of females (P < 0.05). This study could provide better understanding of the posterior maxillary anatomy that is important for the bone-cut design of Le Fort I osteotomy to avoid excessive intraoperative and postoperative hemorrhage including ischemia of the mobilized maxilla.

Opisthorchis viverrini: ultrastructure and cytochemistry of the glycocalyx of the tegument.

The ultrastructure and cytochemistry of the glycocalyx of the tegument of Opisthorchis viverrini during maturation from newly excysted juvenile to adult stages were investigated using colloidal iron, ruthenium red and lectin stainings. The results showed that the glycocalyx was intensely stained by the first two dyes, thus indicating the presence of relatively high amounts of negative charges. However, the thickness and intensity of the staining decreased during the fluke's maturation. Binding studies using lectin probes on the surface of adult parasites showed that binding sites for Canavalia ensiformis (Con A), Triticum vulgaris (WGA) and Ricinus communis I (RCA I) were present in relative large amounts on the glycocalyx of the adult tegument, whereas those for Dolichos biflorus (DBA) were relatively fewer in number, and those for Ulex europaeus I (UEA I) were absent. The binding patterns of Con A, WGA, RCA I and DBA were generally similar, and the reaction product was uniformly distributed over the dorsal and ventral surfaces of the parasite's body. These bindings, therefore, indicate the presence of D-mannose/D-glucose, N-acetyl-D-glucosamine/sialic acid, D-galactose and N-acetyl-D-galactosamine residues on the glycocalyx of the adult tegument.

Modulation of MMP-2 (gelatinase A) and MMP-9 (gelatinase B) by interferon-gamma in a human salivary gland cell line.

Gelatinases have been shown to be regulated by many cytokines and growth factors, and have been implicated in the pathogenesis of certain autoimmune diseases via tissue destruction. High levels of several cytokines, including IFN-gamma and TNF-alpha, have been demonstrated in the salivary gland microenvironment of patients with Sjogren's syndrome (SS). How these cytokines may be contributing to the pathogenesis of this disease is not well understood. We hypothesized that IFN-gamma with or without (+/-) TNF-alpha could be playing a role in the pathogenesis of SS via the regulation of matrix metalloproteinase (MMP) levels. This study examined the role of IFN-gamma and (+) TNF-alpha in the regulation of the matrix metalloproteinases, MMP-2 (72 kD gelatinase A) and MMP-9 (92 kD gelatinase B). A human salivary gland cell line (HSG) has been used as a possible in vitro model to study the role of IFN-gamma + TNF-alpha in the pathogenesis of SS. The HSG cell line, in the presence of IFN +/- TNF-alpha, displays increased MMP-2 and MMP-9 gelatinolytic activity, protein and RNA levels. The increase in MMP activity was partially blocked with an antibody against the IFN-gamma receptor, and this was associated with a complete inhibition of the previously described IFN-gamma +/- TNF-alpha antiproliferative effect. However, incubation of IFN-gamma treated HSG cells with the synthetic MMP inhibitor BB94 did not alleviate this antiproliferative effect. In addition, we demonstrate that there are very high levels of MMP-9 in the saliva of patients with SS when compared to healthy control subjects. These data suggest that cytokines could be regulating MMP production by salivary epithelial cells and thus indicate a potential role for these cells in the pathogenesis of SS.

Opisthorchis viverrini: effect of praziquantel on the adult tegument.

Ultrastructural changes of the tegument of adult liver flukes, Opisthorchis viverrini, after in vitro incubation in Minimal Essential Medium containing 0, 0.1, 1.0 and 10.0 micrograms/ml of anthelminthic praziquantel for 5, 15, 30, 45 and 60 minutes were investigated by scanning (SEM) and transmission (TEM) electron microscopy. SEM observations showed that the surface damage was composed of blebbing due to the swelling of microvilli, followed later by the disruption of these structures to form lesions that caused the erosion and desquamation of the surface. Sensory papillae, by contrast, appeared relatively unaffected. The surface changes could be observed at all doses but the extent of damage increased with increasing duration of incubation and concentration of the drug. The ventral as well as the dorsal surfaces exhibited similar change, whereas the anterior part tended to be damaged less than the posterior part. Under TEM observations, the earliest sign of changes was the depolymerization of the microtrabecular network in scattered foci, which resulted in the formation of non-membrane-bound vacuoles under microvilli. The basal infoldings also became dilated, and some turned into membrane-bound vacuoles in the basal zone. Subsequently, microvilli became enlarged, and eventually formed blebs that later rupture to form lesion spots as observed in the SEM. Finally, the microtrabecular network in all regions broke down, creating vacuoles of various sizes throughout the tegument, leading to its total disintegration and detachment. The sequence of morphological changes was generally similar at all doses; however, the changes occurred faster at the higher doses and the longer incubation times. In addition, at the longer durations myofilaments in most muscle cells also became depolymerized, while microtubules were unchanged by the drug. Therefore, it is possible that praziquantel, through its induction of Ca2+ influx, causes depolymerization of the microtrabecular network that leads to the vacuolization, swelling, blebbing, and eventually the disruption and detachment of the tegument, and the breakdown of myofilaments in the muscle cells.

Opisthorchis viverrini: the effects of colchicine and cytochalasin B on the adult tegument.

The roles of the tegumental cytoskeleton were tested by treating adult flukes with colchicine and cytochalasin B. Following a short incubation period (10-20 minutes), colchicine disrupted microtubules in the tegumental cells' processes which, in turn, affected the transport of dense granules from the cells' soma to the tegument; as a result some of these granules were fused together to form membrane-bound vacuoles. In addition, at many spots microtrabeculae were also depolymerized, which resulted in the formation of non-membrane-bound vacuoles and the distension of microvilli to form blebs, some of which were disrupted. After prolonged incubation (120 minutes), general breakdown of the tegumental cytoskeleton occurred, and parts of it were sloughed off. In cytochalasin B treatment, the responses were similar to those of colchicine but with less severity. After a short incubation period (10-20 minutes), the microtrabeculae were depolymerized which led to the formation of non-membrane-bound vacuoles in the apical and middle zones of the tegument. Later, the tegumental microvilli were distended to form blebs but no evidence of tegumental sloughing occurred even in prolonged incubation. From these observations, it was concluded that microtubules played a role in the translocation of granules from the tegumental cells to the tegument which modulated the synthesis of membrane and glycocalyx, while microtrabeculae were involved in the maintenance of the structure and integrity of the tegument.

Opisthorchis viverrini: the tegumental cytoskeleton.

The tegumental cytoskeleton of Opisthorchis viverrini was observed using both conventional transmission electron microscopy and Triton X-100 extraction. The cytoskeletal elements of the newly excysted juveniles, first-week and adult stages are composed of 2 components: firstly, the network of knobbed fibres designated as microtrabeculae which form the principal scaffold of the cytoplasm; and secondly, the microtubules. The microtrabeculae are more densely packed in the newly excysted juveniles and become less densely packed later in the first-week and adult stages. Generally, their compactness in the tegument of each stage is higher in the apical and middle zones than in the basal zone. The results from extraction by Triton X-100 suggest that the microtrabeculae may be composed, at the primary level, of thin and straight fibres, partly coiled up to form knobbed fibres, which are highly cross-linked at the secondary level. At the tertiary level, these knobbed fibres may be coiled up further and form closely aggregated globules that appear as dense dots in cross-section. Most microtubules are confined within the tegumental cells' processes and splay out in the basal zone of the tegument. In addition, there are condensed laminae of cytoplasm with intermittent dense plaques underlining the outer membrane, with microtrabecular fibres inserting into them. This organization may help to stabilize the outer membrane and preserve the surface contour. Along the inner membrane of the tegument, there are hemidesmosomes distributed at regular intervals, with fine fibres radiating out from them to intertwine with the microtrabecular network, which may help to anchor the tegument to the basal lamina. Spines, which exist mainly in the newly excysted juveniles, appear as a crystalline lattice structure whose bases are firmly fused to the inner membrane.

Opisthorchis viverrini: ultrastructure of the tegument of the first-week juveniles and adult flukes.

The tegument of one-week-old and adult flukes of Opisthorchis viverrini were studied by transmission electron microscopy. The tegument of both stages is composed of a syncytium formed by processes of the tegumental cells lying underneath the outer-circular and the inner-longitudinal muscle layers. The tegument is bounded by trilaminate outer and inner membranes; the former is coated with a thin glycocalyx, while the latter has short basal infoldings. There are 4 forms of tegumental granules, namely dense spherical, dense discoid, light spherical and light discoid granules. Dense spherical and dense discoid granules have similar dense homogeneous and highly electron-dense matrices; thus, they may represent different planes of sections of biconcave granules, and may contribute their content to the formation of the outer membrane and the glycocalyx. Light spherical and light discoid granules may be another type of granule whose filamentous content may contribute to the formation of the microtrabecular network in the tegument. Microvilli start to develop in one-week-old juveniles and become fully developed in adult stages. The size, number and cristae of the mitochondria become increasingly more numerous along with the development of microvilli; in the first-week juveniles most mitochondria are located in the basal portion of the tegument while in adults most lie within microvilli underneath the outer membrane. The tegumental cell is irregular in shape and contains a nucleus with a prominent nucleus, abundant rough endoplasmic reticulum, well developed Golgi complexes, ribosomes, mitochondria and numerous tegumental granules.(ABSTRACT TRUNCATED AT 250 WORDS)

Length and caudal level of termination of the spinal cord in Thai adults.

An analysis of the lengths of spinal cords was conducted using data from 129 adult Thais, 73 males and 56 females, who ranged in age from 20 to 95 years with an average age of 66.6 +/- 16.6 years. The lengths of spinal cords ranged from 30 to 49 cm with a mean of 40.8 +/- 3.2 cm. The average cord length in males (42.3 +/- 2.5 cm) was significantly greater than that in females (38.9 +/- 3.1 cm; p < 0.05). The site of caudal termination of the spinal cord varied from the middle third of the twelfth thoracic vertebra to the upper third of the third lumbar vertebra. The mean level of cord termination was located opposite the intervertebral disc between the first and the second lumbar vertebrae, and there was no significant difference between the sexes (p > 0.05). The length of the vertebral column was also measured in 16 cases. It ranged from 64.5 to 70.5 cm with an average of 68.4 +/- 3.5 cm. There was a significant correlation between the length of the spinal cord and the length of the vertebral column (p < 0.01).

Opisthorchis viverrini: changes of the tegumental surface in newly excysted juvenile, first-week and adult flukes.

The tegumental surface of the newly excysted juvenile, first-week and adult stages of a human liver fluke, Opisthorchis viverrini, was studied by scanning electron microscopy. The surface of the newly excysted juvenile is characterized by circumferentially arranged ridges alternated with troughs which bear rows of spines encircling the body. These spines are characterized by the shapes of their edges: the first type with serrated edge appears on the anterior part, and the second type with single sharp edge appears on the middle part. There are no spines on the posterior part of the body. Three types of presumed sensory papillae are present: type A is a single small cone-shaped ciliated papilla; type B is a group of ciliated papillae on a common dome-shaped base; and type C is a large papilla with nonciliated bulb. Type A papillae are scattered evenly on the surface but are more concentrated around the oral and ventral suckers, as well as the excretory pore. Pairs of both type A and B papillae are located in rows along the lateral surfaces of the body. Type C papillae are located solely on the lip of the ventral sucker. In the first-week fluke the tegumental surface appears corrugated and covered with short developing microvilli, and spines are mostly lost. In the fully-grown adult fluke the surface appears highly corrugated with wave-like folds encircling the body which are covered in turn with closely packed stubby microvilli. Microvilli are more numerous and are taller on the ventral than on the dorsal surface. Among microvilli on the surface of both older stages three types of sensory papillae as in the newly excysted juvenile were observed, but they are of larger sizes. The number of type A papilla increases whereas that of type B papilla decreases during maturation. The distribution of papillae in both stages is similar to the newly excysted stage.