Ex Vivo Regional Mechanical Characterization of Porcine Pulmonary Arteries.

BACKGROUND: Regional mechanical characterization of pulmonary arteries can be useful in the development of computational models of pulmonary arterial mechanics. OBJECTIVE: We performed a biomechanical and microstructural characterization study of porcine pulmonary arteries, inclusive of the main, left, and right pulmonary arteries (MPA, LPA, and RPA, respectively). METHODS: The specimens were initially stored at -20°C and allowed to thaw for 12-24 hours prior to testing. Each artery was further subdivided into proximal, middle, and distal regions, leading to ten location-based experimental groups. Planar equibiaxial tensile testing was performed to evaluate the mechanical behavior of the specimens, from which we calculated the stress at the maximum strain (S 55), tensile modulus (TM), anisotropy index (AI), and strain energy in terms of area under the stress-strain curve (AUC). Histological quantification was performed to evaluate the area fraction of elastin and collagen content, intima-media thickness (IMT), and adventitial thickness (AT). The constitutive material behavior of each group was represented by a five-constant Holzapfel-Gasser-Ogden model. RESULTS: The specimens exhibited non-linear stress-strain characteristics across all groups. The MPA exhibited the highest mean wall stress and TM in the longitudinal and circumferential directions, while the bifurcation region yielded the highest values of AI and AUC. All regions revealed a higher stiffness in the longitudinal direction compared to the circumferential direction, suggesting a degree of anisotropy that is believed to be within the margin of experimental uncertainty. Collagen content was found to be the highest in the MPA and decreased significantly at the bifurcation, LPA and RPA. Elastin content did not yield such significant differences amongst the ten groups. The MPA had the highest IMT, which decreased concomitantly to the distal LPA and RPA. No significant differences were found in the AT amongst the ten groups. CONCLUSION: The mechanical properties of porcine pulmonary arteries exhibit strong regional dissimilarities, which can be used to inform future studies of high fidelity finite element models.

Effects and side-effects of spironolactone therapy in women with acne.

BACKGROUND AND AIMS: Androgen hormones play an important role in the pathogenesis of acne. Despite the demonstrated effects, spironolactone, an androgen receptor blocker, is not commonly used to treat acne. We planned an open-labelled, prospective study to evaluate the effects and side-effects of spironolactone therapy in women with acne. MATERIALS AND METHODS: Thirty-five consecutive patients with acne were treated with spironolactone 100 mg/day, 16 days each month for 3 months. The patients were divided according to the clinical severity of the lesions as having mild, moderate and severe acne. Serum total testosterone and dehydroepiandrosterone sulfate (DHEAS) levels were measured before and after treatment. Lesion numbers and hormone levels before and after treatment were compared with one-sampled t-test. RESULTS: The mean age of the patients was 21.4 +/- 3.5 years. Two patients discontinued the study due to side-effects. Five patients were lost in the follow-up. Clinically significant improvement was noted in 24 patients (85.71%). No response was seen in four patients. All of the nonresponding patients had received previous unsuccessful therapies. Mean number of lesions and mean DHEAS levels of the 24 patients with clinical improvement decreased significantly after treatment (P < 0.01 and P < 0.05, respectively). There was no change in the mean total testosterone levels before and after treatment (P > 0.05). CONCLUSION: Spironolactone is a safe and effective medication for women with acne vulgaris. Although its side-effects seem to be high, they are in the majority of cases not a reason to stop treatment.

Serum iron, ferritin, folic acid, and vitamin B12 levels in recurrent aphthous stomatitis.

BACKGROUND: The exact aetiology of recurrent aphthous stomatitis (RAS) is still unknown, but different predisposing factors, including iron, vitamin B12 and folic acid deficiencies, have been proposed. MATERIAL AND METHODS: Serum iron, ferritin, folic acid and vitamin B12 levels were investigated in 35 patients with RAS and in 26 healthy controls. RESULTS: Vitamin B12 levels were found significantly lower in subjects with RAS than in controls. No significant differences were found in other parameters. CONCLUSION: We concluded that vitamin B 12 deficiency may be an aetiological factor in recurrent aphthous stomatitis.

Immunologic status in children with brain tumors and the effect of therapy.

The cellular and humoral immunological parameters (leucocyte, granulocyte, lymphocyte, total T, T4, T8 lymphocyte counts, lymphoproliferative response to PHA [LP-PHA], natural killer cell activity [NKCA], IgG, IgM and IgA levels) of 20 pediatric brain tumor patients were investigated before and after chemo-(CT) and radiotherapy (RT) administered according to the UIOI-PBT-91 protocol. The T4 and T8 cell percentages and the LP-PHA values before therapy were found to be significantly diminished in comparison to values obtained from 12 healthy children (p < 0.05). In patients receiving postoperative CT, all cellular immunity parameters except T8 cell number and NKCA; IgG and IgA levels were significantly decreased after two courses of CT (p < 0.05). In 7 patients given postoperative RT, a depression in all cellular immunity parameters was observed (p < 0.05). In 6 patients treated with 2 courses of postoperative CT followed by RT administered concomitantly with low dose CDDP, there was a decrease in all cellular and humoral immunity parameters, which was not found to be significant. In 5/18 patients infectious episodes in mild to moderate severity were observed, none causing mortality. It was concluded that the UIOI-PBT-91 protocol caused cellular immunosuppression both after CT and after RT and some humoral immunosuppression after CT, but was found to be tolerable in regard to acute immunological side effects.