Quantification of the magnification and distortion effects of a pediatric flexible video-bronchoscope

Background

Flexible video bronchoscopes, in particular the Olympus BF Type 3C160, are commonly used in pediatric respiratory medicine. There is no data on the magnification and distortion effects of these bronchoscopes yet important clinical decisions are made from the images. The aim of this study was to systematically describe the magnification and distortion of flexible bronchoscope images taken at various distances from the object.

Methods

Using images of known objects and processing these by digital video and computer programs both magnification and distortion scales were derived.

Results

Magnification changes as a linear function between 100 mm (×1) and 10 mm (×9.55) and then as an exponential function between 10 mm and 3 mm (×40) from the object. Magnification depends on the axis of orientation of the object to the optic axis or geometrical axis of the bronchoscope. Magnification also varies across the field of view with the central magnification being 39% greater than at the periphery of the field of view at 15 mm from the object. However, in the paediatric situation the diameter of the orifices is usually less than 10 mm and thus this limits the exposure to these peripheral limits of magnification reduction. Intraclass correlations for measurements and repeatability studies between instruments are very high, r = 0.96. Distortion occurs as both barrel and geometric types but both types are heterogeneous across the field of view. Distortion of geometric type ranges up to 30% at 3 mm from the object but may be as low as 5% depending on the position of the object in relation to the optic axis.

Conclusion

We conclude that the optimal working distance range is between 40 and 10 mm from the object. However the clinician should be cognisant of both variations in magnification and distortion in clinical judgements.     

Bony ankylosis of the temporomandibular joint: follow-up of 70 patients treated with arthroplasty and acrylic spacer interposition

This paper presents the author's experience with interpositional arthroplasty using an acrylic cylinder in 70 cases of bony ankylosis of the temporomandibular joint. Ankylosis followed trauma in all but one patient. The diagnosis was established when restriction of mouth opening was associated with roentgenologic evidence of deformation of the condyle, obliteration of the joint space, and abnormal bone formation in and around the joint. The pathologic changes were classified into four types depending on severity, and each type influenced the treatment. Surgical treatment included creation of a transversely elliptical gap between the two bony components of the joint using a neurosurgical burr and perforator and a chisel through a preauricular approach and interposition of an acrylic cylinder. This maintained the gap, facilitated movement, and encouraged nonunion. The results following a long follow-up of 2 to 10 years showed uniformly good results with a range of mouth opening varying from 2 to 5 cm. Only three bilateral cases recurred and two others had a limited range of mouth opening, with interincisor distance varying from 2 to 2.5 cm.     

Comparison of Glucose Lowering Effect of Metformin and Acarbose in Type 2 Diabetes Mellitus: A Meta-Analysis

BackgroundMetformin is the first-line oral hypoglycemic agent for type 2 diabetes mellitus recommended by international guidelines. However, little information exists comparing it with acarbose which is also commonly used in China. This study expanded knowledge by combining direct and indirect evidence to ascertain the glucose lowering effects of both drugs.MethodsPubMed (1980- December 2013) and China National Knowledge Infrastructure databases (1994-January 2014) were systematically searched for eligible randomized controlled trials from Chinese and English literatures. Meta-analysis was conducted to estimate the glucose lowering effects of metformin vs. acarbose, or either of them vs. common comparators (placebo or sulphonylureas), using random- and fixed-effect models. Bucher method with indirect treatment comparison calculator was applied to convert the summary estimates from the meta-analyses into weighted-mean-difference (WMD) and 95% confidence intervals (CIs) to represent the comparative efficacy between metformin and acarbose.ResultsA total of 75 studies were included in the analysis. In direct comparison (8 trials), metformin reduced glycosylated hemoglobin (HbA_1c) by 0.06% more than acarbose, with no significant difference (WMD,-0.06%; 95% CI, -0.32% to 0.20%). In indirect comparisons (67 trials), by using placebo and sulphonylureas as common comparators, metformin achieved significant HbA_1c reduction than acarbose, by -0.38% (WMD,-0.38%, 95% CI, -0.736% to -0.024%) and -0.34% (WMD, -0.34%, 95% CI, -0.651% to -0.029%) respectively.ConclusionThe glucose lowering effects of metformin monotherapy and acarbose monotherapy are the same by direct comparison, while metformin is a little better by indirect comparison. This implies that the effect of metformin is at least as good as acarbose''s.     

Sperm competition and the evolution of sperm design in mammals

Background  

The influence of sperm competition upon sperm size has been a controversial issue during the last 20 years which remains unresolved for mammals. The hypothesis that, when ejaculates compete with rival males, an increase in sperm size would make sperm more competitive because it would increase sperm swimming speed, has generated contradictory results from both theoretical and empirical studies. In addition, the debate has extended to which sperm components should increase in size: the midpiece to accommodate more mitochondria and produce more energy to fuel motility, or the principal piece to generate greater propulsion forces.     

Polyamine research in plants – a changing perspective

Our understanding of the precise role(s) of polyamines (PAs) in various plant developmental and morphogenetic processes has advanced considerably by the ability to manipulate PA biosynthetic pathways using polyamine biosynthesis inhibitors, PA- mutants and by adopting various transgenic strategies. The cDNA for almost every biosynthesis pathway enzyme has been isolated and cloned in a number of systems. This review briefly summarizes our current understanding of the genetic control of PA metabolism in different model plant systems.     

The translation initiation complex eIF3 in trypanosomatids and other pathogenic excavates – identification of conserved and divergent features based on orthologue analysis

Background

The initiation of translation in eukaryotes is supported by the action of several eukaryotic Initiation Factors (eIFs). The largest of these is eIF3, comprising of up to thirteen polypeptides (eIF3a through eIF3m), involved in multiple stages of the initiation process. eIF3 has been better characterized from model organisms, but is poorly known from more diverged groups, including unicellular lineages represented by known human pathogens. These include the trypanosomatids (Trypanosoma and Leishmania) and other protists belonging to the taxonomic supergroup Excavata (Trichomonas and Giardia sp.).

Results

An in depth bioinformatic search was carried out to recover the full content of eIF3 subunits from the available genomes of L. major, T. brucei, T. vaginalis and G. duodenalis. The protein sequences recovered were then submitted to homology analysis and alignments comparing them with orthologues from representative eukaryotes. Eleven putative eIF3 subunits were found from both trypanosomatids whilst only five and four subunits were identified from T. vaginalis and G. duodenalis, respectively. Only three subunits were found in all eukaryotes investigated, eIF3b, eIF3c and eIF3i. The single subunit found to have a related Archaean homologue was eIF3i, the most conserved of the eIF3 subunits. The sequence alignments revealed several strongly conserved residues/region within various eIF3 subunits of possible functional relevance. Subsequent biochemical characterization of the Leishmania eIF3 complex validated the bioinformatic search and yielded a twelfth eIF3 subunit in trypanosomatids, eIF3f (the single unidentified subunit in trypanosomatids was then eIF3m). The biochemical data indicates a lack of association of the eIF3j subunit to the complex whilst highlighting the strong interaction between eIF3 and eIF1.

Conclusions

The presence of most eIF3 subunits in trypanosomatids is consistent with an early evolution of a fully functional complex. Simplified versions in other excavates might indicate a primordial complex or secondary loss of selected subunits, as seen for some fungal lineages. The conservation in eIF3i sequence might indicate critical functions within eIF3 which have been overlooked. The identification of eIF3 subunits from distantly related eukaryotes provides then a basis for the study of conserved/divergent aspects of eIF3 function, leading to a better understanding of eukaryotic translation initiation.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-1175) contains supplementary material, which is available to authorized users.