Rectal swabs are a reliable method of assessing the colonic microbiome

BackgroundAdvances in genome sequencing have enabled detailed microbiome analysis; however, the ideal specimen type for sequencing is yet to be determined. Rectal swabs may offer a rapid and convenient modality for colonic microbiome analysis. The aim of this study is to evaluate the use of rectal swabs compared to faecal specimens.Methods and resultsTwenty health professionals participated in this study and provided a faecal specimen, a self-collected rectal swab and a rectal swab taken by a clinician. DNA was extracted and 16S rRNA gene sequencing was carried out for microbiome analysis.Alpha diversity was higher in swabs compared to faecal specimens; however, the difference was only significant when comparing clinician-obtained swabs to faeces.Analysis of beta diversity consistently showed that few taxa were affected by sample type. We found sample type accounted for only 6.8% of community variation (R2 = 0.067, p < 0.001, permanova). Notably, there were only six genera identified in clinician-obtained swabs that were not also found in the self-taken swabs.ConclusionsBoth self-collected and clinician obtained rectal swabs are a reliable method of analysing the colonic microbiome. Obtaining specimens for microbiome analysis is often time-critical due to therapy, such as antibiotics, influencing the microbiome. Rectal swabs are shown to be a valid and convenient modality for microbiome analysis.     

The malignancy grading method is not a reliable assessment of malignancy in mesothelioma

The ploidy of a series of pleural lesions--reactive proliferations, malignant mesotheliomas and metastatic tumours--was measured on a Leitz Miamed DNA image analyser using Feulgen-stained slides. The technique successfully recognized all the metastatic tumours as malignant; this corresponds to previous work. However, it was not successful in classifying mesothelial lesions as benign or malignant, resulting in a very high false-negative rate and a moderately high false-positive rate. Mesothelial lesions appear to have a wide range of ploidy values irrespective of their biological behaviour. Thus, for primary mesothelial tumours, the ploidy value cannot be used as a reliable diagnostic index.     

MRCP compared to diagnostic ERCP for diagnosis when biliary obstruction is suspected: a systematic review

Background  

Magnetic resonance cholangiopancreatography (MRCP) is an alternative to diagnostic endoscopic retrograde cholangiopancreatography (ERCP) for investigating biliary obstruction. The use of MRCP, a non-invasive procedure, may prevent the use of unnecessary invasive procedures. The aim of the study was to compare the findings of MRCP with those of ERCP by the computation of accuracy statistics.     

A comparison of alignment using patient specific guides,computer navigation and conventional instrumentation in total knee arthroplasty

BackgroundPatient specific guides (PSG) have been introduced as a tool in total knee arthroplasty (TKA) in an attempt to improve limb alignment and reduce operative time compared to other established surgical techniques. The purpose of this study was to compare the post-operative radiographic alignment and operative time in patients who underwent TKA surgery with PSG, conventional instrumentation or computer-assisted navigation surgery using fully cemented components.MethodsA cohort of 260 patients who underwent TKA surgery using PSG (PSG group, n = 115) was compared to patients who underwent TKA using either conventional instrumentation (CON group, n = 92) or computer-assisted navigation (CAS group, n = 53). Post-operative CT imaging using the Perth CT protocol was used to compare alignment between the three groups.ResultsIn the PSG and CAS groups, the post-operative hip–knee angle (HKA) was within 3° of neutral alignment in 91.3% and 90.7% of patients, respectively. This compared to 80.4% of patients in the CON group (p = 0.02). There were no significant differences with respect to alignment when comparing individual component positioning between the PSG and CAS groups apart from tibial slope (Table 3). Total operative time was found to be significantly reduced in the PSG group (80.2 min) compared to both the CON group (86 min, p = 0.002) and the CAS group (110.2 min, p < 0.0001).ConclusionsThe use of PSG resulted in similar alignment accuracy to CAS and superior alignment to CON with significantly shorter operative times.     

Facial thermography is a sensitive and specific method for assessing food challenge outcome

BACKGROUND: Oral challenge is widely used for diagnosing food allergy but variable interpretation of subjective symptoms may cause error. Facial thermography was evaluated as a novel, objective and sensitive indicator of challenge outcome. METHODS: A total of 24 children with a history of egg allergy underwent oral challenge, which were scored positive when objective symptoms occurred or negative after all doses were consumed without reaction. Facial temperatures were recorded at baseline and 10-min intervals. The difference between mean and baseline temperature (DeltaT), maximum DeltaT during challenge (DeltaT(max)) and area under curve of DeltaT against time (DeltaTAUC) were calculated for predefined nasal, oral and forehead areas, and related to objective challenge outcome. RESULTS: There were 13 positive and 11 negative challenges. Median nasal DeltaTAUC and DeltaT(max) were greater in positive compared with negative challenges (231- and 5-fold, respectively; P < 0.05). In positive challenges, nasal temperatures showed an early transient rise at 20 min, preceding objective symptoms at median 67 min. There was a sustained temperature increase from 60 min, which was reduced by antihistamines. A cut-off for nasal DeltaT(max) of 0.8 degrees C occurring within 20 min of the start of the challenge predicted outcome with 91% sensitivity (positive predictive value [PPV] 100%) and 100% specificity (negative predictive value [NPV] 93%). Subjective symptoms occurred in four of 13 positive and three of 11 negative challenges. CONCLUSIONS: Facial thermography consistently detects a significant early rise in nasal temperature during positive compared with negative food challenges, which is evident before objective symptoms occur. Thermography may therefore provide a sensitive method to determine outcome of food challenges and investigate the pathophysiology of food allergic reactions.     

Multilocus sequence typing is a reliable alternative method to DNA fingerprinting for discriminating among strains of Candida albicans

Multilocus sequence typing (MLST) has emerged as a powerful new DNA-typing tool for the evaluation of intraspecies genetic relatedness. This method relies on DNA sequence analysis of nucleotide polymorphisms in housekeeping genes and has shown a high degree of intraspecies discriminatory power for bacterial and fungal pathogens. However, the results of the MLST scheme for Candida albicans have heretofore never been formally compared to those of other established typing techniques. To assess the value of MLST relative to those of other DNA fingerprinting tools for discriminating among strains of C. albicans, we applied it to a previously well-characterized set of 29 C. albicans isolates evaluated by the random amplified polymorphic DNA (RAPD), multilocus enzyme electrophoresis (MLEE), and Ca3 Southern hybridization probe techniques. MLST identified three clusters of genetically related isolates, with 82.3% direct concordance with MLEE, 82.7% with RAPD analysis, and 86.2% with the Ca3 Southern hybridization technique. When MLST was applied to a subset of 22 isolates of unrelated origins, it identified 21 independent diploid sequence types (DSTs), resulting in a discriminatory power of 99.6%. These DSTs were 96.9, 99.6, and 99.6% concordant with the genotypes identified by RAPD analysis, MLEE, and Ca3 Southern hybridization, respectively. These results demonstrate that MLST is a highly effective technique that performs at least comparably to other established DNA fingerprinting techniques.     

The histological preparation of bronchial brushings–a reliable and satisfactory method

A method for improving the diagnostic yield of fibreoptic bronchoscopic bronchial brushings and tiny biopsies has been developed. This technique has proved reliable giving a high positive yield of malignant cells and tissue in the 232 specimens examined.     

Under-correction of preoperative varus alignment does not lead to a difference in in-vivo bone loading in 3D-SPECT/CT compared to neutral alignment

BackgroundThe aim was to investigate the correlation of bone tracer uptake (BTU) in SPECT/CT and changes in coronal knee alignment after total knee arthroplasty (TKA). We questioned if undercorrection of preoperative varus alignment leads to a difference in BTU compared to neutral alignment.MethodsConsecutive 66 patients who received SPECT/CT before and after TKA were retrospectively included. Adjusted mechanical alignment was the alignment target. The alignment of the knee was measured on 3D-CT by selecting standardized landmarks. Maximum (mean ± SD) and relative BTU (ratio to the reference) were recorded using a previously validated localization scheme (p < 0.05).ResultsIn the native group, 20 knees were aligned (30.3%) in valgus (HKA > 181.5°), 12 (18.2%) in neutral (178.5°-181.5°) and 34 (51.5%) in varus (HKA < 178°). Overall TKA changed the alignment towards neutral. 48.5% remained in the same groups, whereas 50% of native valgus and 33% of varus knees changed to neutral after TKA. In native varus alignment mean BTU was significantly higher in some medial tibial and femoral regions (fem1ia (p = 0.010), fem1ip (p = 0.002), tib1a.mid (p = 0.005), tib1a.tray (p = 0.000), tib1p.tray (p = 0.000)); in native valgus alignment mean BTU was higher in the corresponding lateral tibial and femoral regions (fem2ip (p = 0.001), tib2a.tray (p = 0.011), tib2p.tray (p = 0.002)). After TKA, a significant decrease in femoral and tibial BTU (femoral preoperative BTU 1.64 +/-0.69; femoral postoperative BTU 0.95 +/-0.42; p = 0.000// tibial preoperative BTU 1.65 +/- 0.93; tibial postoperative BTU 1.16 +/- 0.48; p = 0.000) and an increase in patellar BTU was observed (p = 0.025). Native varus alignment correlated with a higher medial BTU decrease medially. Undercorrection of preoperative varus alignment showed no higher BTU after TKA.ConclusionPreoperative varus alignment correlated with a higher decrease in BTU in specific femoral and tibial medial regions. Preoperative valgus alignment correlated with a higher decrease in the corresponding lateral regions. Undercorrection of preoperative varus alignment did not lead to higher bone loading reflected by BTU after TKA.     

Effectiveness of a computer tailored physical activity intervention in adolescents compared to a generic advice

Objective

To investigate the differences in effects of a computer tailored physical activity advice as compared to generic information in adolescents.

Methods

Students (mean age, 14.6 ± 1.2) out of 90 classes from six different Flemish schools were randomly assigned to the tailored intervention (n = 563) or the generic non-tailored intervention (n = 608) condition. Both interventions included information on public health recommendations and tips on becoming more active. Participants in both groups received their assessment and feedback at baseline, at 4 weeks and at 3 months during school hours. Physical activity levels were determined using an adolescent adaptation of the International Physical Activity Questionnaire (IPAQ).

Results

After 4 weeks, almost all physical activity scores increased over time in both the generic and the tailored intervention group. No differences between groups were found (all F ≤ 0.07). After 3 months, the generic intervention was more effective for increasing ‘walking in leisure time’ among students not complying with recommendations. For all other physical activity scores, no differences between groups were found (all F ≤ 2.3).

Conclusions

In contrast to the expectations, changes in physical activity scores did not differ between the tailored and the non-tailored intervention group. For most of the physical activity scores increases were found in both groups.     

Quantification of joint alignment and stability during a single leg stance task in a knee osteoarthritis cohort

Background

Knee osteoarthritis alters joint stability but its kinematics during functional weight-bearing tasks remain unclear. We propose and validate an assessment technique for the quantification of knee alignment and stability in patients during a short single leg stance task.

Cervicovaginal self-sampling is a reliable method for determination of prevalence of human papillomavirus genotypes in women aged 20 to 30 years

Self-sampling by cervicovaginal lavage could be an attractive method to detect high-risk human papillomavirus (hr-HPV) infections to identify women with a risk of cervical precancer. The objective of our study was to use self-sampling for the first time in a cross-sectional approach to determine HPV prevalence and genotype distribution. We evaluated participants' acceptance and laboratory results from self-obtained samples versus endocervical brush samples obtained by gynecologists. To determine the sensitivity of both sampling methods in presumed high- and low-prevalence settings, two groups of women 20 to 30 years of age with (n = 55) and without (n = 101) a recent suspicious cytological smear were compared. Overall, 76% (95% confidence interval [95% CI], 65 to 88) of women with and 40% (95% CI, 30 to 49) of women without a recent suspicious cytological smear tested HPV positive. The prevalences of high-risk HPV strains were 71% (95% CI, 59 to 83) and 32% (95% CI, 22 to 41), respectively, for these two groups. The agreement for hr-HPV between the two sampling methods for women with and without suspicious cytology was 84% (κ = 0.65; 95% CI, 0.44 to 0.86) and 91% (κ = 0.78; 95% CI, 0.64 to 0.92), respectively. Participants rated the user-friendliness of the self-sampling method on a visual analog scale from 0 (easy) to 100 (difficult) with a median of 12. In conclusion, self-sampling by cervicovaginal lavage is a reliable method to determine hr-HPV prevalence and is well accepted by young adult females.     

Detection of Y-specific sequences in 122 patients with Turner syndrome: nested PCR is not a reliable method

The incidence of Y chromosome sequences in patients with Turner syndrome has been evaluated in several studies, and its frequency varied from 0% to 61%, depending on the molecular methodology used. The aim of our study was to screen for Y chromosome sequences in 122 patients with Turner syndrome without cytogenetic evidence of this chromosome. DNA of 100 normal women was also screened and it was used as a negative control. To identify cryptic Y mosaicism, eight regions of Y chromosome were amplified by PCR. In order to increase the sensitivity of Y sequence detection, a nested PCR of the SRY and TSPY genes was also performed. All patients had several stigmata of Turner syndrome and none of them presented with signs of virilization. The most frequent karyotype was 45,X (54.1%), followed by mosaicism involving structural aberration of the X chromosome. There were 12 patients who carried a marker or ring chromosome. First-round PCR identified Y chromosome sequences in only four patients (3%), and all of them had a chromosome mosaicism with at least one cell lineage with a marker chromosome. After nested PCR, 25% of the patients and 14% of the normal women were positive for the presence of Y sequences. Contamination with extraneous genomic DNA was ruled out by microsatellite studies, but we cannot eliminate the possibility of contamination with PCR products, despite careful handling. We conclude that nested PCR overestimated the frequency of Y sequences in patients with Turner syndrome and should be avoided to prevent false positive results, which lead to unnecessary surgical treatment of these patients.