Analysis of reversed L-loops as closing loops with anterior intrusive force

Objective: Intrusive forces on anterior brackets are preferable for avoiding overbite deepening. Reversing plain L-loops may create such advantageous force system during space closure.

Design: Force systems of reversed L-loops were compared with T-loops at three interbracket distances (IBD).

Setting: Computational study.

Methods: Using finite element analysis, loop response during simulated loop-pulling was determined for plain reversed L- and T-loop configurations at three IBDs and two sizes. Force systems were calculated on both loop ends for two activation forces.

Results: The 12?mm IBD reversed L-loops had almost equal M/F ratios in opposite directions at both ends. A small intrusive force was found at the canine bracket (CB). The 6?mm IBD reversed L-loops showed larger M/F ratios and extrusive forces at the premolar bracket (PB) and smaller M/F with intrusive forces at CB. The force system of 12?mm IBD T-loops showed the similar force systems as off-centered V-bends with extrusive force at CB, whilst plain 6?mm IBD T-loops showed properties similar to centered V-bends with less extrusive force at CB.

Conclusions: Reversed L closing loops placed no extrusive force on the CB end at various IBDs, indicating that reversed loops will generate an intrusive force at anterior teeth during space closure.     

Roles of liver fluke infection as risk factor for cholangiocarcinoma

Several factors are known to be associated with risk of cholangiocarcinoma (CCA) and infection with the liver flukes, Opisthorchis viverrini and Clonorchis sinensis, has often been singled out as the leading risk factor in east and southeast Asia. In this review, current knowledge of their biology, life cycle, and pathogenesis of O. viverrini, and its role as a carcinogenic parasite are presented. The trends of age‐specific incidence of liver cancer in Khon Kaen, northeast Thailand are considered and compared with the prevalence profiles of O. viverrini. Potential impacts of the liver fluke control program particularly by mass drug administration (MDA) and public health education in the past and a recent drop of incidence of CCA are discussed in relation to primary prevention and control of this fatal bile duct cancer.     

Panniculitis in tuberculosis: a clinicopathologic study of nodular panniculitis associated with tuberculosis

Background Certain types of panniculitis, erythema induratum of Bazin and erythema nodosum, have been well documented as tuberculids. Many histopathologic diagnoses of panniculitis have been reported in tuberculosis patients. This study investigates the correlation between underlying tuberculosis and clinicopathologic findings of panniculitis.
Methods We retrospectively reviewed the clinical files of histologic-proven panniculitis cases at the Dermatologic Clinic, Siriraj Hospital from January 1992 to December 1995; only cases with active tuberculous foci were analyzed.
Results The incidence of panniculitis caused by tuberculosis was 8.2%. The ratio of men to women was 1 : 1. The mean age of onset was 35.3 years. The average duration of the nodules was 35.5 days. There was a history of contact tuberculosis in 16.6%. Constitutional symptoms and a strongly positive purified protein derivative (PPD) reaction were found in 66.6%. Chest roentgenograms were abnormal in 83.3%. The erythrocyte sedimentation rate was elevated in all tested cases. The histopathologic diagnoses were nodular vasculitis (33.3%), erythema nodosum (50%), and cutaneous periarteritis nodosa (16.4%). The panniculitis lesion responded to standard antituberculous regimens in 4.6 weeks, on average, with residual hyperpigmentation.
Conclusions In panniculitis patients, clues for the investigation of tuberculosis included constitutional symptoms, elevated erythrocyte sedimentation rate, and abnormal chest roentgenograms. Histopathologic changes of panniculitis did not seem to correlate with underlying tuberculosis. The clinician should be aware of the tuberculosis, however, and should carefully search for active foci in all panniculitis patients.     

Gastric volvulus caused by percutaneous endoscopic gastrostomy: a case report

Percutaneous endoscopic gastrostomy is commonly performed for enteric feeding in children with neurologic impairment because of its low rates of complication. We report a case of gastric volvulus, an unusual complication, after percutaneous endoscopic gastrostomy procedure in our institution.     

Protection of Xanthomonas against arsenic toxicity involves the peroxide-sensing transcription regulator OxyR

Arsenic has been shown to mediate its toxicity through induced generation of reactive oxygen species. Here, we examined the role of oxidative stress-inducible genes (katA, ahpC and ohr) and their regulators (oxyR and ohrR) in the response to arsenic treatment in a plant pathogenic bacterium, Xanthomonas campestris pv. phaseoli (Xp). Overproduction of peroxide-scavenging enzymes (KatA, AhpCF and Ohr) did not enhance arsenic tolerance in wild-type Xp. Furthermore, inactivation of katA, ahpC, ohr, and ohrR genes had no effect on the level of arsenic resistance. By contrast, an oxyR mutant (Xp oxyR) showed increased sensitivity to both pentavalent arsenate and, to a greater extent, trivalent arsenite. The resistance of cells to arsenite treatment was significantly affected by the level of iron. Cells were 10-fold more sensitive to arsenite killing in the presence of excess iron, while removal of iron by an iron chelator (2,2'-dipyridyl) protected Xanthomonas from arsenite toxicity. The arsenite-sensitive phenotype of Xp oxyR could be complemented by the expression of functional OxyR from a plasmid vector, but not by the expression of other known OxyR-regulated peroxide-scavenging enzymes such as KatA and AhpCF, Ohr and OhrR. The data suggested that as yet unidentified, OxyR-regulated gene(s) are involved in conferring arsenic resistance in Xp. To our knowledge, this is the first report showing that the peroxide-sensing regulator OxyR is involved in arsenic resistance.     

Genetic relationships within the Opisthorchis viverrini species complex with specific analysis of O. viverrini from Savannakhet, Lao PDR by multilocus enzyme electrophoresis

Recent systematic studies of Opisthorchis viverrini based on multilocus enzyme electrophoresis (MEE) have shown that there are at least five genetic groups and possibly two cryptic species occurring in Thailand and Lao PDR each associated with a specific wetland system. A study based on mitochondrial DNA (mtDNA) gene analyses of an O. viverrini population from Savannakhet (SV, Lao PDR) clustered with several isolates from Thailand and Lao PDR although they originated from different river wetland systems. We used MEE to re-examine whether O. viverrini from SV was similar genetically to isolates from Thailand and Lao PDR. The allelic profiles of O. viverrini from SV and five different wetlands representing defined genetic groups of O. viverrini were recorded at 24 enzyme loci as opposed to only two loci of mtDNA. Contrary to previous studies, O. viverrini from SV was found to have fixed genetic differences at six to eight of the 24 loci examined (24.50–35.42%). Allelic data indicated that O. viverrini from SV differed from isolates in the Nam Ngum River wetland in Lao PDR (29.33% fixed genetic differences) and clustered with O. viverrini from Nakhon Phanom and Sakon Nakhon within the Songkram River wetland in Thailand but had fixed genetic differences from these at 24.5% of loci examined. Our data confirm the association between genetic groups of O. viverrini and specific wetland systems, and raise important questions regarding the significance of the genetic differences and relationships of O. viverrini from these wetlands.     

Isolated tuberculosis of tunica vaginalis in a child

We reported a case of tuberculosis of tunica vaginalis which can present as an acute scrotum.     

Pentalateral osteotomy for cubitus varus. Clinical experiences of a new technique

Several methods for the correction of cubitus varus have been described, but most reported series are small and show a high rate of complications. We report a six-year personal experience of 77 osteotomies by a new technique which provides rigid fixation and allows correction of both varus and rotation deformities. It also prevents lateral bulging at the level of the osteotomy. In 58 cases followed up for an average of 16 months, there were no serious complications, a satisfactory carrying angle and no significant loss of movement, giving 88% excellent or good results.     

Genetic characterization of Echinostoma revolutum and Echinoparyphium recurvatum (Trematoda: Echinostomatidae) in Thailand and phylogenetic relationships with other isolates inferred by ITS1 sequence

Echinostomatidae are common, widely distributed intestinal parasites causing significant disease in both animals and humans worldwide. In spite of their importance, the taxonomy of these echinostomes is still controversial. The taxonomic status of two species, Echinostoma revolutum and Echinoparyphium recurvatum, which commonly infect poultry and other birds, as well as human, is problematical. Previous phylogenetic analyses of Southeast Asian strains indicate that these species cluster as sister taxa. In the present study, the first internal transcribed spacer (ITS1) sequence was used for genetic characterization and to examine the phylogenetic relationships between an isolate from Thailand with other isolates available from GenBank database. Interspecies differences in ITS1 sequence between E. revolutum and E. recurvatum were detected at 6 (3%) of the 203 alignment positions. Of these, nucleotide deletion at positions 25, 26, and 27, pyrimidine transition at 50, 189, and pyrimidine transversion at 118 were observed. Phylogenetic analysis revealed that E. recurvatum from Thailand clustered as a sister taxa with E. revolutum and not with other members of the genus Echinoparyphium. Interestingly, this result confirms a previous report based on allozyme electrophoresis and mitochondrial DNA that E. revolutum and E. recurvatum in Southeast Asia are sister species. Hence, the taxonomic status of E. recurvatum in Thailand, as well as in Southeast Asian countries needs to be confirmed and revised using more comprehensive analyses based on morphology and other molecular techniques.