Effects of maximal effort strength training with different loads on dynamic strength, cross-sectional area, load-power and load-velocity relationships

The effects of maximal effort strength training with different loads on maximal strength, muscle cross-sectional area, the load-power and load-velocity relationship were investigated in the elbow flexors. Physical education students were matched into three groups; G90 (n = 9) trained with a load of 90%. G35 (n = 11) with 35%, and G15 (n = 10) with 15% of IRM (1 repetition maximum). Training consisted of three to five sets, performed three times a week for 9 weeks. Each set consisted of two, seven and ten repetitions in G90. G35 and G15, respectively. Training was performed with the nondominant arm, and the dominant arm served as control. The IRM increased 15.2 (SD 4.5)% (P < 0.001) in G90, 10.1 (SD 5.9)% (P < 0.001) in G35 and 6.6 (SD 7.9)% (P < 0.05) in G15. The increase in G90 was significantly larger than for G15 (P < 0.05). In the untrained arm, IRM also increased for G90 and G15. In contrast to G90. G15 showed a similar increase in IRM in both arms. Cross-sectional area of the elbow, flexors did not change for G90 and G15. while G35 increased 2.8% (P < 0.05). Maximal power and velocity were tested at 2.5 kg and at 15%, 25%, 35%, 50%, 70% and 90% of pretraining IRM. Power increased for all tested loads in G90 and G35, and G15 showed an increase in power at 15%, 25% and 50% of IRM. No significant differences in increase in power could be found among the three groups at loads equal to or less than 50%, but at 70% and 90% of IRM the increase was larger for G90 and G35 than for G15 (P < 0.05). The G35 showed a similar increase in power at all loads tested whereas G90 showed load specificity in the effect of the training. There was a correlation between IRM and maximal power (r = 0.93, P < 0.0001), and between IRM and power at load 2.5 kg (r = 0.73, P < 0.0001). In conclusion, training with loads of 15% and 35% of IRM resulted in an increase in IRM. Although the increase in maximal power after training at 90% of IRM showed some load specificity. It also increased maximal power at 15% of IRM. Training at loads near maximal power output would seem to increase power efficiently over a wide load range. The high correlation between IRM and maximal power at load 2.5 kg also would indicate that maximal strength is important for performance at light loads.

Probiotic treatment reduces depressive-like behaviour in rats independently of diet

The gut microbiota has recently emerged as an important regulator of brain physiology and behaviour in animals, and ingestion of certain bacteria (probiotics) therefore appear to be a potential treatment for major depressive disorder (MDD). However, some conceptual and mechanistical aspects need further elucidation. We therefore aimed at investigating whether the habitual diet may interact with the effect of probiotics on depression-related behaviour and further examined some potentially involved mechanisms underlying the microbe-mediated behavioural effects. Forty male Sprague-Dawley rats were fed a control (CON) or high-fat diet (HFD) for ten weeks and treated with either a multi-species probiotic formulation or vehicle for the last five weeks. Independently of diet, probiotic treatment markedly reduced depressive-like behaviour in the forced swim test by 34% (95% CI: 22-44%). Furthermore, probiotic treatment skewed the cytokine production by stimulated blood mononuclear cells towards IFNγ, IL2 and IL4 at the expense of TNFα and IL6. In addition, probiotics lowered hippocampal transcript levels of factors involved in HPA axis regulation (Crh-r1, Crh-r2 and Mr), whereas HFD increased these levels. A non-targeted plasma metabolomics analysis revealed that probiotics raised the level of indole-3-propionic acid, a potential neuroprotective agent. Our findings clearly support probiotics as a potential treatment strategy in MDD. Importantly, the efficacy was not attenuated by intake of a "Western pattern" diet associated with MDD. Mechanistically, the HPA axis, immune system and microbial tryptophan metabolism could be important in this context. Importantly, our study lend inspiration to clinical trials on probiotics in depressed patients.

The microbial metabolite indole-3-propionic acid improves glucose metabolism in rats, but does not affect behaviour

CONTEXT

We have previously shown that an antidepressant-like effect of probiotics in rats was associated with a higher plasma level of the microbial tryptophan metabolite indole-3-propionic acid (IPA).

OBJECTIVE

We therefore wanted to study the isolated effect of IPA on behaviour and glucose metabolism in rats.

METHODS

Male Sprague-Dawley rats were fed control or IPA-enriched diet for six weeks (n = 12 per group) and assessed in the elevated plus maze, open field and forced swim test. Blood glucose, metabolic hormones and the white blood cell (WBC) composition were analysed.

RESULTS

IPA (mean intake 27.3 mg/kg/day) significantly lowered fasting blood glucose level by 0.42 mM (95% CI 0.11-0.73). Similarly, fasting plasma insulin levels and the homeostatic model assessment (HOMA) index of insulin resistance were reduced, whereas plasma metabolic hormones, behaviour and WBC composition remained unaffected by IPA.

CONCLUSIONS

Our findings highlight IPA as a promising candidate for treatment of metabolic disorders associated with insulin resistance.

A high-fat diet exacerbates depressive-like behavior in the Flinders Sensitive Line (FSL) rat, a genetic model of depression

Major depressive disorder (MDD) and diabetes mellitus type II (T2DM) are two of the major health challenges of our time. It has been shown that MDD and T2DM are highly co-morbid, and recent work has proposed a bi-directional connection between the diseases. The aim of the current study was to investigate the effect of a high-fat diet (HFD) on behavior and metabolism in a genetic rat model of depression, the Flinders Sensitive and Resistant Line (FSL/FRL) rats. Age and weight matched rats were fed a HFD or control diet for 10 weeks and subjected to behavioral testing and metabolic assessment. We found that HFD exacerbated the depressive-like behavior of the FSL rat in the Forced Swim Test (FST), a depression screening tool, although it did not affect the non-depressed FRL rat despite a higher caloric intake. Moreover, the depressive-like phenotype was associated with reduced anxiety and impairment in novel object recognition memory, while HFD consumption led to diminished object recognition memory as well. In both strains HFD increased insulin levels during an oral glucose tolerance test, although fasting blood glucose levels were only significantly increased by HFD in the FSL rat, suggesting a greater metabolic susceptibility in this rat strain. We conclude that compared with the FRL rat, the FSL rat is more susceptible to developing aberrant behaviors related to depression following metabolic stress induced by HFD. Further studies with a mechanistic focus could potentially lead to a better understanding of a possible pathophysiological link between T2DM and MDD.

Altered fecal microbiota composition in the Flinders sensitive line rat model of depression

RATIONALE

The gut microbiota is increasingly recognized as a potential mediator of psychiatric diseases. Depressed patients have been shown to have a different microbiota composition compared with healthy controls, and several lines of research now aim to restore this dysbiosis. To develop novel treatments, preclinical models may provide novel mechanistic insights.

OBJECTIVE AND METHODS

We characterized the gut microbiota of male adult Flinders sensitive line (FSL) rats, an animal model of depression, and their controls, Flinders resistant line (FRL) rats using 16S rRNA amplicon sequencing. Moreover, we performed fecal microbiota transplantation (using saline or pooled FRL/FSL feces) to study if the potential strain-specific differences could be transferred from one strain to the other, and if these differences were reflected in their depressive-like behavior in the forced swim test.

RESULTS

FSL rats tended to have lower bacterial richness and altered relative abundances of several bacterial phyla, families, and species, including higher Proteobacteria and lower Elusimicrobia and Saccharibacteria. There was a clear separation between FRL and FSL rat strains, but no effect of treatment, i.e., the bacterial composition of FSL rats receiving FRL feces was still more similar to FSL and not FRL rats. Similarly, the transplantation did not reverse behavioral differences in the forced swim test, although FSL feces significantly increased immobility compared with saline.

CONCLUSIONS

Our study showed that the gut microbiota composition of the depressive-like rats markedly differed from their controls, which may be of value for future microbiota-targeted work in this and similar animal models.

Probiotic treatment protects against the pro-depressant-like effect of high-fat diet in Flinders Sensitive Line rats

Major depressive disorder (MDD) is highly associated with dysmetabolic conditions, such as obesity and diabetes mellitus type 2, and the gut microbiota may interact with both disease entities. We have previously shown that a high-fat diet (HFD) exacerbated depressive-like behaviour uniquely in Flinders Sensitive Line (FSL) rats that inherently present with an increased level of depressive-like behaviour compared with Flinders Resistant Line (FRL) rats. We therefore investigated whether multispecies probiotics possessed anti-depressant-like effect in FSL rats or protected against the pro-depressant-like effect of HFD. We also examined blood and cerebral T cell subsets as well as plasma cytokines. Lastly, we investigated the effect of HFD in outbred Sprague-Dawley (SD) rats to substantiate the association between depressive-like behaviour and any immunological measures affected by HFD. HFD exacerbated the depressive-like behaviour in FSL rats in the forced swim test, whereas SD rats remained unaffected. Probiotic treatment completely precluded the pro-depressant-like effect of HFD, but it did not affect FSL rats on control diet. Cerebral T lymphocyte CD4/8 ratios closely mirrored the behavioural changes, whereas the proportions of Treg and Th17 subsets were unaltered. No association between blood and brain CD4/8 ratios were evident; nor did plasma cytokine levels change as a consequence of HFD of probiotic treatment. Our findings suggest that MDD may hold a dysmetabolic component that responds to probiotic treatment. This finding has wide implications owing to the high metabolic comorbidity in MDD. Furthermore, the close association between depressive-like behaviour and cerebral T cell populations demonstrate lymphocyte-brain interactions as a promising future research area in the field of psychoneuroimmunology.

Computed tomography/magnetic resonance based volume changes of the primary tumour in patients with prostate cancer with or without androgen deprivation

BACKGROUND AND PURPOSE

To evaluate changes of the volume of the cancerous prostatic gland during androgen deprivation (AD) started immediately after diagnosis (IAD). Hypothetically, these data would assist the radiotherapist to determine the appropriate duration of pre-radiotherapy downsizing neoadjuvant luteinizing hormone releasing hormone (LHRH) treatment. A second aim was to assess any increase of the prostatic volume during the 1st year of diagnosis in patients who were allocated to a deferred treatment policy (DAD). METHODS AND MATERIALS Thirteen patients in the IAD cohort and 13 patients in the DAD group, all with T1-3pN1-2M0 prostate cancer, had regular computed tomography/magnetic resonance (CT/MR) examinations during the 1st year after randomization within the EORTC-GU trial 30846. Pre-treatment prostate specific antigen (PSA) values were available in only 12 patients.

RESULTS

In the IAD group the prostate gland decreased with significant difference as compared with the DAD patients (P=0.033). As compared with the pre-treatment situation the prostate gland in the IAD group was reduced in size by 18, 35, and 46% at 1, 6, and 12 months, respectively. In four of six evaluable IAD patients the prostatic volume continued to shrink after achievement of the nadir PSA level (at 3 months). In three of the 13 DAD patients the prostate volume increased by >25% during the 1st 3 months after randomization.

CONCLUSION

If neoadjuvant androgen deprivation is applied before local treatment to downsize the volume of the cancerous prostate gland, our limited data suggest that such treatment should last at least 6 months in order to achieve a maximal effect in the majority of patients. In about 1/4 of untreated patients an increase in the prostate volume by >25% may occur within 3 months of diagnosis. If no AD is given, radiotherapy should start within this period.

Dosage of Anticoagulants in Obesity: Recommendations Based on a Systematic Review

Anticoagulants are frequently used as thromboprophylaxis and in patients with atrial fibrillation (AF) or venous thromboembolism (VTE). While obesity rates are reaching epidemic proportions worldwide, the optimal dosage for obese patients has not been established for most anticoagulants, including low-molecular-weight heparin (LMWH), non-vitamin K antagonist oral anticoagulants (NOAC), and pentasaccharides (fondaparinux). The aim of the present systematic review was to summarize the current knowledge and provide recommendations on dosage of LMWH, NOAC, and fondaparinux in obese patients (body mass index [BMI] ≥ 30 kg/m² or body weight ≥ 100 kg). Based on a systematic search in PubMed and Embase, a total of 72 studies were identified. For thromboprophylaxis with LMWH in bariatric surgery (n = 20 studies), enoxaparin 40 mg twice daily, dalteparin 5,000 IE twice daily, or tinzaparin 75 IU/kg once daily should be considered for patients with BMI ≥ 40 kg/m². For thromboprophylaxis with LMWH in nonbariatric surgery and in medical inpatients (n = 8 studies), enoxaparin 0.5 mg/kg once or twice daily or tinzaparin 75 IU/kg once daily may be considered in obese patients. For treatment with LMWH (n = 18 studies), a reduced weight-based dose of enoxaparin 0.8 mg/kg twice daily should be considered in patients with BMI ≥ 40 kg/m², and no dose capping of dalteparin and tinzaparin should be applied for body weight < 140 kg. As regards NOAC, rivaroxaban, apixaban, or dabigatran may be used as thromboprophylaxis in patients with BMI < 40 kg/m² (n = 4 studies), whereas rivaroxaban and apixaban may be administered to obese patients with VTE or AF, including BMI > 40 kg/m², at standard fixed-dose (n = 20 studies). The limited available evidence on fondaparinux (n = 3 studies) indicated that the treatment dose should be increased to 10 mg once daily in patients weighing > 100 kg.

The antidepressant-like effect of probiotics and their faecal abundance may be modulated by the cohabiting gut microbiota in rats

Numerous studies have been published describing the effect of various probiotics (PRO) on behaviours related to psychiatric disease. We have previously shown a robust antidepressant-like effect of PRO in rats, but over time, the treatment effect seems to vary significantly between different sets of rats from the same commercial vendor. Therefore, we hypothesised that the antidepressant-like response may be modulated by the cohabiting gut microbiota. The aims of the present study were (1) to investigate any differences in the gut microbiota composition between responders (Resp) and non-responders (Non-resp) to PRO with regards to depressive-like behaviour, and (2) to evaluate the effects of PRO on the microbiota composition. Two sets of 20 male Sprague-Dawley rats each were treated with multi-species PRO (nine Bifidobacterium, Lactococcus and Lactobacillus species) for eight weeks and subjected to a behavioural assessment. Faecal samples were collected for 16 s rRNA (VR4) gene amplicon sequencing (Illumina MiSeq). As previously reported, PRO-treated Resp animals showed a marked decrease in depressive-like behaviour, whereas no such response was seen in Non-resp. We observed profound differences in the gut microbiota composition between the two sets of rats, and the relative faecal abundance of the genera that comprised PRO was higher in Resp than in Non-resp although treated with the same dose of PRO. Particularly, the relative abundance of the Lactobacillus genus was not increased in PRO-treated Non-resp animals. In conclusion, the cohabiting microbiota and the faecal abundance of PRO may modulate the antidepressant-like effect of PRO in rats.

Reference intervals for plasma vitamin B12 and plasma/serum methylmalonic acid in Danish children, adults and elderly

BACKGROUND

Plasma/serum vitamin B12 (B12) is often used to screen for B12 deficiency complemented with analysis of methylmalonic acid (MMA) in case of low B12. The concentration of both analytes likely depends on age, and we, therefore, aimed at establishing 95% age-adjusted reference intervals (RIs) for plasma B12 and serum/plasma MMA in the Danish population.

METHODS

We collected and analysed blood samples from healthy children, adults, and elderly individuals and extracted routine clinical B12 and MMA results to establish RIs. We also evaluated the association between matching B12 and MMA results.

RESULTS

We suggest the following RIs for plasma B12 and plasma/serum MMA, respectively. 0-<1 year: 180-1400 pmol/L, 0.10-1.25 µmol/L; 1-<11 years: 260-1200 pmol/L, 0.10-0.30 µmol/L; 12-<18 years: 200-800 pmol/L, 0.10-0.35 µmol/L; 18-<65 years: 200-600 pmol/L, 0.10-0.40 µmol/L; 65 + years: 200-600 pmol/L, 0.12-0.46 µmol/L. Finally, the proportion of patients with elevated MMA differed between age groups independently of B12 and was highest in children.

CONCLUSION

We propose new age-adjusted RIs for B12 and MMA and suggest that age-dependent cut-off values should be implemented if plasma B12 is used to screen for B12 deficiency.

Quantitative renal cortical perfusion in human subjects with magnetic resonance imaging using iron-oxide nanoparticles: influence of T1 shortening

BACKGROUND

Using conventional contrast agents, the technique of quantitative perfusion by observing the transport of a bolus with magnetic resonance imaging (MRI) is limited to the brain due to extravascular leakage.

PURPOSE

To perform quantitative perfusion measurements in humans with an intravascular contrast agent, and to estimate the influence of the T1 relaxivity of the contrast agent on the first-pass response.

MATERIAL AND METHODS

Renal cortical perfusion was measured quantitatively in six patients with unilateral renal artery stenosis using a rapid gradient double-echo sequence in combination with an intravenous bolus injection of NC100150 Injection, an intravascular contrast agent based on iron-oxide nanoparticles. The influence of T1 relaxivity was measured by comparing perfusion results based on single- and double-echo data.

RESULTS

The mean values of cortical blood flow, cortical blood volume, and mean transit time in the normal kidneys were measured to 339+/-60 ml/min/100 g, 41+/-8 ml/100 g, and 7.3+/-1.0 s, respectively, based on double-echo data. The corresponding results based on single-echo data, which are not compensated for the T1 relaxivity, were 254+/-47 ml/min/100 g, 27+/-3 ml/100 g, and 6+/-1.2 s, respectively.

CONCLUSION

The use of a double-echo sequence enabled elimination of confounding T1 effects and consequent systematic underestimation of the perfusion.

A diet-induced gut microbiota component and related plasma metabolites are associated with depressive-like behaviour in rats

It is well-established in preclinical studies that various probiotics may improve behaviours related to psychiatric disease. We have previously shown that probiotics protected against high-fat diet (HFD)-induced depressive-like behaviour in Flinders Sensitive Line (FSL) rats, whereas FSL rats on control (CON) diet were unaffected. Therefore, we hypothesised that a dysmetabolic component of depression may exist that involves the gut microbiota and that such component may be reflected in the plasma metabolome. The aims of the present study post hoc analyses were 1) to study the effect of probiotics on gut microbiota composition and its association with depressive-like behaviour in FSL rats, and 2) to identify plasma metabolites associated with gut microbiota and depressive-like behaviour. Forty-six FSL rats were fed CON or HFD and treated with multi-species probiotics (nine Bifidobacterium, Lactococcus and Lactobacillus species) for 12 weeks. Faecal samples were collected for 16S rRNA (VR4) gene amplicon sequencing (Illumina MiSeq), and an untargeted plasma metabolomics was performed. We found that probiotics increased the relative faecal abundance of the Bifidobacterium, Lactococcus and Lactobacillus genera in HFD-fed rats only. Also, a HFD-induced microbiota component associated with depressive-like behaviour was identified, and probiotics improved the component score. Finally, the plasma levels of 44 metabolites correlated with the depression-related microbiota component, and three such metabolites had good predictive ability for depressive-like behaviour. Potentially, our findings imply that a subtype of depression characterised by a diet-induced, pro-depressant gut microbiota may exist and that analysis of related plasma metabolites may reveal aberrant microbiota functioning related to depression.

A pressure-recording guidewire for measuring arterial transstenotic gradients: in vivo validation

RATIONALE AND OBJECTIVES

We used an 0.018-inch guidewire with a pressure sensor to measure arterial transstenotic pressure gradients. Our aim was to evaluate the pressure-recording properties of this device in vivo.

METHODS

Stenoses in the common carotid artery of piglets were created with external cylindrical constrictors. Pressures and pressure gradients were measured with the pressure wire and compared with reference measurements and with a 3.1-French fluid-filled catheter.

RESULTS

The averages of several pressure measurements were close to the reference, but there were individual deviations. Twenty-nine percent of zero-corrected systolic measurements deviated more than 5 mm Hg from the reference, and 10% deviated more than 10 mm Hg. Errors canceled out somewhat in gradient measurements.

CONCLUSION

Although some measurement errors were found, the guidewire represents an important new concept for gradient measurements. The small diameter minimizes gradient augmentation caused by the measuring device lying across the stenosis. Further refinement would increase its usefulness.

Use of sonicated albumin (Infoson) to enhance arterial spectral and color Doppler imaging

PURPOSE

To examine the effect of an ultrasound contrast medium (UCM), Infoson, on Doppler examination of stenotic arteries.

METHODS

Stenoses were created in the common carotid artery of six piglets, and examined with spectral Doppler and color Doppler imaging during UCM infusion in the left ventricle.

RESULTS

UCM caused a mean increase in recorded maximal systolic and end-diastolic velocities of 5% and 6%, respectively, while blood flow remained constant. Increased spectral intensity with UCM was accompanied by spectral broadening. Reduction of spectral intensity by adjustment of Doppler gain counteracted the velocity effects and the spectral broadening. With color Doppler, UCM caused dose-dependent color artifacts outside the artery. Flow in narrow stenoses could be visualized with UCM.

CONCLUSION

The effects of UCM on velocity measurements were slight, and were related to changes in spectral intensity. With color Doppler, UCM may facilitate flow detection, but color artifacts may interfere.

Effect of ultrasound contrast medium in color Doppler and power Doppler visualization of blood flow in canine kidneys

PURPOSE

To examine the effect of an ultrasound contrast medium (UCM) in the visualization of parenchymal blood flow by means of color Doppler and power Doppler sonography.

MATERIAL AND METHODS

Nonenhanced and UCM-enhanced Doppler images of canine kidneys were obtained in a transversal plane during various states of flow reduction in the anterior branch of the renal artery. The UCM consisted of air-filled shell-stabilized microballoons (half-life approximately 2 min). The images were evaluated blindly by 4 observers who rated the amount of flow signal in the cortex and medulla, and categorized the flow state (normal, reduced or no flow) in the anterior part of the kidney.

RESULTS

The UCM increased the area of Doppler signals in the cortex and outer medulla during normal or reduced blood flow. The border between nonperfused and normally perfused parenchyma was more distinct with the UCM. The categorization of the regional flow state was more correct with the UCM. Improvement with the UCM was greatest when the nonenhanced Doppler images had suboptimal intensity, but positive effects with the UCM were also seen in recordings with adequate precontrast intensity. Color blooming artifacts sometimes occurred on the side of the kidney facing away from the transducer.

CONCLUSION

The UCM improved the color Doppler and power Doppler visualization of the parenchymal blood flow in the canine kidney, and allowed a more correct categorization to be made of the regional blood flow state.

Increasing contrast when viewing radiographic images

Illuminating a developed photographic film with parallel or nearly parallel light provides increased contrast compared with the contrast obtained with diffuse incident light. The viewer of radiographic images can obtain increased contrast simply by increasing the distance between the view box and the radiograph, since this results in more parallel incident light. The authors found a contrast increase of more than 40% when x-ray film was positioned 4 m from a view box. Tilting the film relative to the surface plane of the view box gave additional contrast increase at the cost of somewhat distorted geometry. The photographic effects involved deserve a more thorough discussion in textbooks of radiologic and radiographic physics.

Comparison of 12-Bit and 8-Bit Gray Scale Resolution in Mr Imaging of the CNS

A reduction in gray scale resolution of digital images from 12 to 8 bits per pixel usually means halving the storage space needed for the images. Theoretically, important diagnostic information may be lost in the process. We compared the sensitivity and specificity achieved by 4 radiologists in reading laser-printed films of original 12-bit MR images and cathode ray tube displays of the same images which had been compressed to 8 bits per pixel using a specially developed computer program. Receiver operating characteristic (ROC) curves showed no significant differences between film reading and screen reading. A paired 2-tailed t-test, applied on the data for actually positive cases, showed that the combined, average performance of the reviewers was significantly better at screen reading than at film reading. No such differences were found for actually negative cases. Some individual differences were found, but it is concluded that gray scale resolution of MR images may be reduced from 12 to 8 bits per pixel without any significant reduction in diagnostic information.

Lot variation and inter-device differences contribute to poor analytical performance of the DCA Vantage™ HbA1c POCT instrument in a true clinical setting

OBJECTIVES

The glycated haemoglobin fraction A_1c (HbA_1c) is widely used in the management of diabetes mellitus, and the Siemens DCA Vantage™ point-of-care testing (POCT) instrument offers rapid HbA_1c results even far from a clinical laboratory. However, the analytical performance has been questioned, and not much is known about effects of changing reagent lot, instrument and operator. We therefore compared the analytical performance of the DCA Vantage™ with established routine methods (Tosoh G8/G11 ion exchange HPLC) in a true clinical setting at two Danish hospitals.

METHODS

We extracted all routine clinical HbA_1c results incidentally drawn from the same patient within 48 h (n=960 pairs) and evaluated the effect of reagent lot, operator and instrument. We also performed a prospective method comparison in our diabetes out-patient clinic (n=97).

RESULTS

The critical difference (CD) between two POCT results varied between 5.14 and 6.61 mmol/mol (0.47-0.55%), and the analytical imprecision of the DCA Vantage™ (CV_A) was >3%. Significant effect of reagent lot and inter-instrument differences were found, whereas no effect of operator was seen.

CONCLUSIONS

The DCA Vantage™ HbA_1c analysis does not fulfil the prevailing analytical performance specifications, but rigorous validation of new reagent lots and continuous recalibration of instruments may potentially improve the precision substantially. Our findings, therefore, clearly emphasise the necessity of a close collaboration between clinicians and laboratory professionals in the POCT field. Finally, POCT HbA_1c results should always be interpreted together with other measures of glycaemic control to avoid inappropriate change of patient treatments due to measurement uncertainty.

A pressure-recording guide wire for measurements of trans-stenotic gradients in arteries. In vitro validation

RATIONALE AND OBJECTIVES

A 0.018'' guide wire with a pressure sensor near the tip has been developed for measuring arterial trans-stenotic pressure gradients. The pressure-recording properties of this system in vitro are evaluated.

METHODS

Static and dynamic tests were performed with five guide wires. Dynamic tests (step response and recordings of phase and frequency response) were performed with a pressure generator connected to a recording system and a spectrum analyzer.

RESULTS

Zero drift at 3 hours ranged from -1.9 to 2.2 mmHg/hour. Sensitivity drift ranged from 0.3% to 2.1%/hour. Hysteresis ranged from 0.2% to 4.3% (mean 2.4%). Bending in arcs of 180 degrees with diameters < 4 cm changed sensitivity and zero pressure recordings in all guide wires. Dynamic recordings showed a slight undershoot and no oscillation.

CONCLUSION

Static errors exceeded those of external pressure transducers for fluid-filled catheters, indicating suboptimal recordings of absolute pressures. However, the small size, and the good dynamic properties, make this pressure wire a promising device for recording trans-stenotic pressure gradients in arteries.

Evaluation of a pressure-recording guidewire in patients with coronary arterial disease

The accuracy and feasibility of coronary arterial pressure measurements with a 0.018-in. pressure-recording guidewire (PRGW) was evaluated in patients. Transstenotic pressure gradients were measured with the PRGW and a guiding catheter, at baseline and during coronary vasodilatation. Proximal intracoronary pressure was measured with both systems before and after gradient measurements. Zero pressure was measured with the PRGW before and after intracoronary use. The average of all proximal intracoronary PRGW readings were close to guiding catheter values, but there were substantial individual deviations. Average change in proximal deviation before and after gradient measurements was -1 mm Hg, standard deviation (S.D.) 7.6, range -16 to 15. Errors in zero pressure measurements after intracoronary use (average 2.8 mm Hg, S.D. 8.8, range -9 to 35) were much greater than before use (average 0.1 mm Hg, S.D. 1.4, range -4 to 3, P < 0.001). The PRGW was successfully introduced through an 8F guiding catheter and positioned across the stenosis in 21 of 26 attempts (81%). Intracoronary advancement of the PRGW through a double-lumen multifunctional probing catheter was successful in all nine attempts. In conclusion, errors in PRGW-measurements caused uncertainty in gradient interpretation. However, we found the wire useful in several cases, particularly for exclusion of hemodynamically significant lesions. The steerability of the wire is inferior to ordinary guidewires, but it can be advanced to a distal intracoronary position through an over-the-wire catheter.

Computed Tomography after Modified Whipple Procedure with Pancreatic Duct Occlusion

Eighty-two CT examinations performed on 28 patients who had undergone a modified Whipple procedure including pancreatic duct occlusion were reviewed. Reduction of the antero-posterior diameter of the body and tail of the pancreatic remnant was observed on consecutive scans in 8 patients (29%). Decreasing liver attenuation was seen in 4 patients (14%) postoperatively, and pseudocysts in the pancreatic remnant in 6 (21%). In 10 examinations performed because of suspected intraabdominal abscess postoperatively, abscess was diagnosed in 2 patients. In 62 routine follow-up CT examinations, significant positive findings were diagnosed in 5 patients: tumor recurrence or metastases in 4, and a large pseuodocyst in one. CT is of value in the early postoperative phase to reveal postoperative complications and in the follow-up of patients with specific symptoms indicating tumor recurrence or metastases.

Reference intervals and stability of haptocorrin and holotranscobalamin in Danish children and elderly

BACKGROUND

Haptocorrin (HC) and holotranscobalamin (holoTC) carry vitamin B12 (B12) in the circulation and can be useful biomarkers for evaluating B12 status. The concentration of both proteins depends on age, but data on reference intervals for children and the elderly are sparse. Similarly, not much is known about the effect of preanalytical factors.

METHODS

HC plasma samples from healthy elderly > 65 years (n = 124) were analysed, and both HC and holoTC were analysed in paediatric serum samples ≤ 18 years (n = 400). Furthermore, we investigated assay precision and stability.

RESULTS

HC and holoTC were effected by age. We established reference intervals for HC: 2-10 years, 369-1237 pmol/L; 11-18 years, 314-1128 pmol/L; 65-82 years, 242-680 pmol/L and for holoTC: 2-10 years, 46-206 pmol/L; 11-18 years, 30-178 pmol/L. Analytical coefficients of variations of 6.0-6.8% and 7.9-15.7% were found for HC and holoTC, respectively. HC were affected when stored at room temperature and by freeze/thaw. HoloTC was stable at room temperature and after delayed centrifugation.

CONCLUSION

We present novel 95% age-related reference limits for HC and HoloTC in children, and for HC both in children and elderly. Moreover, we found HoloTC to be fairly stable when stored, whereas HC was more vulnerable to preanalytical factors.