Accurate and Precise Protocol to Estimate the Activity of Peroxiredoxin Enzyme

BACKGROUND

Accurate estimation of Prx activity poses many complications and interferences. The present protocol is free of interference and provides an effective alternative for the assessment of peroxide with high sensitivity. The assay can be used in clinical pathology laboratories since it is simple, rapid, and inexpensive. The systematic reagent consisted of AFS/ASA which acted as a sensitive probe for peroxide.

METHODS

Prx activity was estimated by incubating samples in suitable concentrations of 1,4-dithio-DL-threitol (DTT) and hydrogen peroxide (H2O2) or t-Butyl hydroperoxide (t-BOOH), as the substrates. The enzymatic reaction was inhibited after incubation with a working reagent containing ammonium ferrous sulfate (AFS) and aminosalicylic acid (ASA).

RESULTS

Residual peroxide reacted with the working solution to form a brown-colored ferriaminosalicylate (FAS) complex with a maximum absorbance (λmax) of 425 nm. This protocol used sodium azide (NaN3) to eliminate catalase interference and avoided using high concentrations of strong acid to inhibit the Prx reaction.

CONCLUSION

We concluded that the new protocol produced the same efficacy as the reference method since a strong correlation coefficient of comparison (r> 0.99) was found between both the FAS and ferrithiocyanate method.

Vitamin D status and abdominal aortic calcification in postmenopausal women

Vitamin D has an important role in bone metabolism and may be involved in the process of vascular calcification. The objective of this study was to evaluate the effect of vitamin D status on the presence of abdominal aortic calcification (AAC). We enrolled, in a cross-sectional study, 429 postmenopausal women [mean age, weight, and BMI of 59.5 ± 8.3 (50-83) years, 75.8 ± 13.3 (35-165) kg, and 29.9 ± 5.2 (14.6-50.8) kg/m², respectively]. Lateral vertebral fracture assessment (VFA) images and scans of the lumbar spine and proximal femur were obtained using a Lunar Prodigy densitometer. Vertebral fractures (VFs) were defined using the Genant semiquantitative (SQ) approach. We used the Kauppila score to assess AAC extension. Clinical risk factors of osteoporosis were collected, and 25-hydroxy vitamin D was measured using electrochemiluminescence (Roche). Prevalence of osteoporosis and hypovitaminosis D (<20 ng/ml) was 21.0% and 78.1%, respectively. VFs grade 2/3 were identified in 76 patients (17.7%). Two thirds of the evaluable participants did not have any detectable AAC. The prevalence of significant atherosclerotic burden, defined as a radiographic 24-point AAC score of 5 or higher, was 7.9%. The group of women with extended AAC were older and had a statistically significant higher menopause duration and more prevalent grade 2/3 VFs. Compared to women with normal values of vitamin D, women with vitamin D insufficiency (<20 ng/ml) and deficiency (<10 ng/ml) had a lower BMD and more prevalent VFs. No difference was noted with regard to AAC among the three groups. Multiple stepwise conditional logistic regression analysis showed that the presence of AAC was associated significantly with age and the presence of VFs. Extended aortic calcifications are independently associated with prevalent VFA-identified VFs but not with serum vitamin D levels in postmenopausal women. VFA imaging using DXA may detect at the same time prevalent VFs and AAC, an important cardiovascular disease risk factor.

[Medical treatment of venous priapism apropos of 46 cases: puncture, pharmacologic detumescence or penile cooling?]

OBJECTIVE

To analyse the efficacy of three nonspecific medical approaches to the first-line treatment of priapism : a) intracavernous injection (ICI) of alpha-adrenergic agonists, b) cavernous puncture, c) penile cutaneous cooling.

METHODS

46 cases of venous priapism, due to various aetiologies, were initially treated by ICI of alpha-adrenergic agonists (23 cases), puncture (14 cases) or cooling (9 cases). These 3 methods were combined only in the case of failure and not uniformly, based on our experience. The results were analysed in terms of successful detumescence and preservation of erectile function.

RESULTS

Detumescence was obtained and erectile function was preserved in almost 80% of cases, with conservative treatment alone. ICI (83%) and cooling (78%) were more effective as first-line treatment than puncture (57%). The delay to treatment was a more important parameter than the aetiology. Cooling was no longer effective after the 8th hour, puncture was no longer effective after the 9th hour and ICI was no longer effective after the 34th hour. Failures of conservative treatment and erectile sequelae were only observed in cases of priapism treated after the 24th hour.

CONCLUSION

The 3 methods have a similar degree of efficacy, provided they are performed early. Their indication depends on : 1) the duration of priapism, 2) the presence or absence of cavernosal anoxia. Schematically (and in parallel with aetiological treatment when possible) : a) in the case of painless priapism < 12 hours, cooling can be tried first, b) in the case of failure or painless priapism > 12, but < 24 hours, ICI of alpha-adrenergic agonists associated with puncture is indicated (except in the case of contraindications to ICI), c) in the case of painful priapism or > 24 hours, puncture must be the first treatment. In the case of failure, cavernosal blood gases should be performed to evaluate cavernosal anoxia and to guide management.

[Cholelithiasis and ileo-ceco-cystoplasty (study of 39 patients)]

Limited data have been reported concerning the gallstone complications of ileocaecocystoplasty. A retrospective study of gallbladder ultrasonography looking for gallstones was performed in 35 of 39 patients undergoing ileocaecocystoplasty between July 1987 and July 1991. The surgical technique used in 33 men and 2 women with a mean age of 64.5 years was that described by Thuroff (Mainz Pouch). Gallbladder ultrasonography was performed a fortnight before the operation and then regularly during follow-up, with a mean follow-up of 24 months. Eight patients, an average of 13 months after ileocaecocystoplasty, developed ultrasonographically detectable gallstones, whose prevalence in the male study population was four times higher than that of the general male population. This study raises the question of whether cholecystectomy should be performed routinely during ileocaecocystoplasty and further studies should be conducted to clarify this problem.