The prevalence of an Onodi cell in adult Thai cadavers

Endoscopic sinus surgery in patients who have an Onodi cell (sphenoethmoid cell) carries a high risk for optic nerve injury. We meticulously dissected 65 embalmed cadaver adult half-heads and attempted to identify an optic canal bulge in each with a nasal endoscope. Our aims were to determine the prevalence of an Onodi cell in adult Thai cadavers, to ascertain the prevalence of an overriding ethmoid cell, and to measure the length of an overriding ethmoid cell's superior and posterior extensions in relation to the anterior sphenoid wall. Moreover, we attempted to determine the minimum amount of bone thickness between an Onodi cell and the optic nerve. We found that an Onodi cell was present in 39 of the 65 specimens (60.0%). We also found that an overriding ethmoid cell was present in 14 specimens, which accounted for 21.5% of the total number of specimens and 36.8% of 38 Onodi cell-positive specimens (the presence or absence of an overriding ethmoid cell was not recorded in one of the 39 Onodi cell-positive specimens). The distance of the overriding ethmoid cell's superior and posterior extensions from the anterior sphenoid wall ranged from 3 to 13 mm (median: 7) and from 4 to 16 mm (median: 9.5), respectively. Measurements of the minimum amount of bone thicknesses between each Onodi cell and optic nerve ranged from 0.03 to 0.54 mm (median: 0.08). Our study demonstrated that the prevalence of an Onodi cell in adult Thai cadavers was as great as the prevalence reported in the only other gross anatomic dissection study performed in Asia and much higher than rates generally reported in Western countries.     

A potential new serotype of Riemerella anatipestifer isolated from ducks in Thailand

Eighty isolates of Riemerella anatipestifer representing 71 outbreaks of riemerellosis in Thailand between 1994 and 1999 were serotyped using the gel diffusion precipitin test. Based on the precipitation patterns, 25 serological profiles containing one to three antigenic determinants were recognized. Heat-stable antigens of the organism reacted with antisera raised against 16 known serotypes and an untypable strain 698/95. The most prevalent serotype appeared to be serotype 7, followed by serotypes 5, 10, 21 and 1. Further study demonstrated that the untypable strain probably represents a new serotype. Analysis of the polymerase chain reaction-amplified rrs genes for restriction fragment length polymorphisms verified the inclusion of strain 698/95 within the species R. anatipestifer and supported earlier work excluding strain 670/89, which had originally been designated the reference strain of serotype 20. Therefore, it is suggested that the strain 698/95 could be adopted as a replacement for the reference strain of serotype 20. Attention should be paid to strains with multiple antigenic factors as they may be useful for the preparation of vaccines.     

Rapid and sensitive detection of Penaeus monodon nucleopolyhedrovirus (PemoNPV) by loop-mediated isothermal amplification combined with a lateral-flow dipstick

Several methods such as traditional PCR or nested-PCR, immuno assay and histopathology have been developed for detection of Penaeus monodon nucleopolyhedrovirus (PemoNPV) formerly called monodon baculovirus (MBV). However, these methods have various disadvantages including low sensitivity, long assay time, use of toxic substances or unsuitability for field diagnosis. Loop-mediated isothermal amplification of target nucleotide sequences under isothermal conditions, combined with amplicon detection by chromatographic lateral-flow dipsticks allows for more efficient, field friendly detection within 75 min (not including DNA preparation time). In this study, the LAMP amplicon was biotinylated via an inner LAMP primer designed from a BamHI fragment B, a hypothetical protein gene of PemoNPV under isothermal condition at 63 °C for 1 h. Next, the LAMP product was hybridized at 63 °C for 5 min with an optimal FITC-labeled probe that was designed specifically for the LAMP amplicons. The FITC-labeled biotinylated LAMP product picked up gold-labeled, anti-FITC near the LFD origin and the whole, triple-labeled complex was captured by an immobilized biotin-binding protein to yield a red nano-gold stripe at the LFD test line. With a DNA template extracted from PemoNPV-infected shrimp, the LAMP–LFD detection limit was 0.1 pg, whereas one-step PCR and nested-PCR followed with gel electrophoresis was 1 pg. The LAMP–LFD method gave negative test results with buffer and DNA from shrimp infected with other common shrimp DNA viruses including, Penaeus monodon densovirus (PmDNV) formerly called hepatopancreatic parvovirus (HPV), white spot syndrome virus (WSSV) and Penaeus stylirostris densovirus (PstDNV) formerly called infectious hypodermal and hematopoietic necrosis virus (IHHNV). The test platform can be adapted easily for rapid detection of other shrimp viruses, since the LAMP–LFD combination system was a highly sensitive, specific, convenient, and does not require sophisticated instruments.