Validation of a minimally invasive blood-sampling technique for the analysis of hormones in domestic rabbits, Oryctolagus cuniculus (Lagomorpha)

Previous studies in small mammals showed that blood-sucking bugs (Reduviidae, Heteroptera) can be used to obtain blood from veins difficult to access by human experimenters. In the present study, we validated the use of reduviid bugs for endocrinological studies in endotherms using domestic rabbits as a model organism. Two processes could alter the hormone concentrations in the blood ingested by the bug: (1) Mixing of ingested blood with saliva, gut fluid, or hemolymph and (2) digestive processes. We compared concentrations of progesterone, testosterone, and hydrocortisone in blood samples that were acquired from domestic rabbits (Oryctolagus cuniculus) by bugs (Dipetalogaster maxima) with hormone concentrations in blood obtained from the same individual rabbits with a conventional method, i.e., syringe. We found no significant differences in hormone concentrations between the two methods. Thus, the mixing effect is negligible immediately after the blood meal. In addition, we also could not find significant changes in concentrations of progesterone and hydrocortisone for up to 8h after the blood meal. Whereas levels of hydrocortisone remained unchanged for even 24h, progesterone levels significantly increased between eight and 24h. Thus, the bugs' excretory apparatus did not fractionate between water and hormones. Thirdly, we hypothesized that reduviid bugs impose less stress on the rabbits than the conventional method. We showed that deviations in hydrocortisone concentrations between the two blood sampling routines were lower when the bug method was used first and higher when the conventional method was used first. Thus, bugs imposed less stress on the study animals than the conventional method. Overall, we conclude that reduviid bugs present a minimally invasive method for obtaining blood from endotherm animals for endocrinological studies.     

Connexin 26 mutations and nonsyndromic hearing impairment in northern Finland

OBJECTIVE: The aims of the present study were to evaluate the role of the gap junction protein beta-2 gene (GJB2), encoding connexin 26 (Cx26), in children with moderate to profound prelingual nonsyndromic sensorineural hearing impairment (HI) and to investigate the carrier frequencies of the GJB2 gene mutations in a control population in Northern Finland. METHODS: Mutation analysis was performed by direct sequencing and carrier detection by conformation sensitive gel electrophoresis further confirmed by direct sequencing. RESULTS: Cx26 mutations were found in 15 of 71 (21.1%) (67 families) children with HI. Homozygosity for the mutation 35delG was shown to be the cause of HI in 13 of 15 (86.7%) children. Homozygosity for the M34T genotype was found in one child, and compound heterozygosity for the M34T/V37I genotype was found in another. Five families of those with suspected familial HI (29.4%) and six families out of those with sporadic HI (12.0%) had a homozygous or compound heterozygous mutation. The carrier frequency for the mutation 35delG was 1 of 78 (4 of 313) and that for the M34T was 1 of 26 (12 of 313). CONCLUSION: 35delG/35delG genotype was found to be a significant cause of moderate to profound prelingual nonsyndromic sensorineural HI in Northern Finland. M34T/M34T genotype was seen in only one child, but the carrier frequency of the M34T allele was about three times higher than that of the 35delG mutation.     

Global left-ventricular function assessment using dual-source multidetector CT: effect of improved temporal resolution on ventricular volume measurement

The purpose was to compare global left-ventricular (LV) function parameters measured with cine MRI with results from multiphase dual-source CT (DSCT) using 10 and 20 reconstruction phases. Twenty-eight patients with suspected or known CAD underwent DSCT coronary angiography. LV end-diastolic (EDV), end-systolic (ESV) and stroke volumes (SV), and ejection fraction (EF) were determined using LV segmentation and selection of specific phases from DSCT image sets reconstructed either at 5% or 10% steps through the R-R interval. Cine MRI served as the reference investigation. Threshold-based 3D-segmentation was feasible in all DSCT data sets. EDV and ESV were underestimated by DSCT, but showed excellent correlation (Pearson's correlation coefficient 0.95/0.97) to values obtained with MRI. Using data from 5% DSCT image reconstructions instead of 10% phase reconstructions, the position of the ED and ES phase was changed in 16 of 28 patients; ESVs were to found to be slightly smaller, whereas EDV were slightly larger, resulting in a systematic overestimation of LV EF by 1.9% (p = 0.56). Threshold-based 3D segmentation enables accurate and reliable DSCT determination of global LV function with excellent correlation to cine MRI. Minor differences in LV EF indicate that both modalities are virtually interchangeable, even if the number of reconstructed phases is limited to 10% phase reconstructions.     

Ectopic Beats in Heart Rate Variability Analysis: Effects of Editing on Time and Frequency Domain Measures

Background: Various methods can be used to edit biological and technical artefacts in heart rate variability (HRV), but there is relatively little information on the effects of such editing methods on HRV. Methods: The effects of editing on HRV analysis were studied using R‐R interval data of 10 healthy subjects and 10 patients with a previous myocardial infarction (Ml). R‐R interval tachograms of verified sinus beats were analyzed from short‐term (～5 min) and long‐term (—24 hours) recordings by eliminating different amounts of real R‐R intervals. Three editing methods were applied to these segments: (1) interpolation of degree zero, (2) interpolation of degree one, and (3) deletion without replacement. Results: In time domain analysis of short‐term data, the standard deviation of normal‐to‐normal intervals (SDANN) was least affected by editing, and 30%‐50% of the data could be edited by all the three methods without a significant error (< 5%). In the frequency domain analysis, the method of editing resulted in remarkably different changes and errors for both the high‐frequency (HF) and the low‐frequency (LF) spectral components. The editing methods also yielded in different results in healthy subjects and AMI patients. In 24‐hour HRV analysis, up to 50% could be edited by all methods without an error larger than 5% in the analysis of the standard deviation of normal to normal intervals (SDNN). Both interpolation methods also performed well in the editing of the long‐term power spectral components for 24‐hour data, but with the deletion method, only 5% of the data could be edited without a significant error. Conclusions: The amount and type of editing R‐R interval data have remarkably different effects on various HRV indices. There is no universal method for editing ectopic beats that could be used in both the time‐domain and the frequency‐domain analysis of HRV. A.N.E. 2001;6(1):5–17     

Patient Preferences for Treatment of Low Back Pain—A Discrete Choice Experiment

BackgroundBack pain imposes a substantial economic and social burden, and treatment decisions are distorted by conflicting evidence. Thus, it is important to include patient preferences in decision making and policy making.ObjectiveTo contribute to the understanding of patient preferences in relation to the choice of treatment for low back pain.MethodsA discrete choice experiment was conducted with consecutive patients referred to a regional spine center. The respondents (n = 348) were invited to respond to a choice of two hypothetical treatment options and an opt-out option. The treatment attributes included the treatment modality, the risk of relapse, the reduction in pain, and the expected increase in the ability to perform activities of daily living. In addition, the wait time to achieve the treatment effect was used as a payment vehicle. Mixed logit models were created to perform analysis. Subgroup analysis, dividing respondents into sociodemographic and disease-related categories, further explored the willingness to wait.ResultsRespondents assigned positive utilities to positive treatment outcomes and disutility to higher risks and longer waits for effects of treatment and to surgical interventions. The model captured significant heterogeneity within the sample for the outcomes of pain reduction and the ability to pursue activities of daily living and for the treatment modality. The subgroup analysis revealed differences in the willingness to wait, especially with regard to treatment modality, the level of pain experienced at the time of data collection, and the respondents’ preferences for surgery.ConclusionsThe majority of the respondents prefer nonsurgical interventions, but patients are willing to wait for more ideal outcomes and preferred interventions. The results show that health care professionals have a very important task in communicating clearly about the expected results of treatment and the basis of their treatment decisions, as patients' preferences are highly individual.     

Changes in pain and physical function during waiting time and 3 months after knee joint arthroplasty

OBJECTIVE: To determine changes in physical and social function during a prolonged preoperative waiting period and at 3 months after total knee arthroplasty. SUBJECTS: Forty-three patients were evaluated on the day that surgery was decided, the day before surgery, and 3 months afterwards. METHODS: Knee pain and function were assessed using a visual analogue scale and a functional assessment system. Isometric knee flexion extension strength and mobility were measured. RESULTS: Knee pain and muscle strength remained unchanged during the mean waiting time of 10 (standard deviation 8) months. On the affected side, knee extension strength was 19% weaker than on the contralateral side and did not change pre-operatively. Post-operatively, knee pain decreased by 50%. Knee extension strength decreased by 26% and flexion strength by 12% compared with the initial assessments. Knee extension strength of the operated side was 42% lower than on the non-operated side. Knee flexion mobility was decreased by 8%, while the initially detected knee extension deficit of 10 degrees (SD 7) remained unchanged. The functional assessment system did not detect any changes in function. CONCLUSION: Waiting time did not affect knee pain or isometric knee extension/flexion strength. Three months post-operatively, knee pain had decreased significantly, but the strength of the operated knee was significantly lower than the pre-operative level.