Antihypertensive mechanisms of chronic captopril or N-acetylcysteine treatment in L-NAME hypertensive rats.

Hypertension due to chronic inhibition of NO synthase (NOS) by Nomega-nitro-L-arginine methyl ester (L-NAME) administration is characterized by both impaired NO-dependent vasodilation and enhanced sympathetic vasoconstriction. The aim of our study was to evaluate changes in the participation of major vasoactive systems in L-NAME-treated rats which were subjected to simultaneous antihypertensive (captopril) or antioxidant (N-acetylcysteine, NAC) treatment. Three-month-old Wistar males treated with L-NAME (60 mg/kg/day) for 5 weeks were compared to rats in which L-NAME treatment was combined with simultaneous chronic administration of captopril or NAC. Basal blood pressure (BP) and its acute responses to consecutive i.v. injections of captopril (10 mg/kg), pentolinium (5 mg/kg), L-NAME (30 mg/kg), tetraethylammonium (TEA, 16 mg/kg) and nitroprusside (NP, 20 microg/kg) were determined in conscious rats at the end of the study. The development of L-NAME hypertension was prevented by captopril treatment, whereas NAC treatment caused only a moderate BP reduction. Captopril treatment normalized the sympathetic BP component and significantly reduced residual BP (measured at full NP-induced vasodilation). In contrast, chronic NAC treatment did not modify the sympathetic BP component or residual BP, but significantly enhanced NO-dependent vasodilation. Neither captopril nor NAC treatment influenced the compensatory increase of TEA-sensitive vasodilation mediated by endothelium-derived hyperpolarizing factor in L-NAME-treated rats. Chronic captopril treatment prevented L-NAME hypertension by lowering of sympathetic tone, whereas chronic NAC treatment attenuated L-NAME hypertension by reduction in the vasodilator deficit due to enhanced NO-dependent vasodilation.     

Repair of thoracic aortic aneurysm due to noninfectious aortitis

Abstract Background and aim: Isolated thoracic aortitis (ITA) is a newly‐defined pathological entity with a still‐unknown etiopathology and with some potential relationship to IgG4‐related systemic disease. We investigated patients on whom the ascending aorta was operated to identify the clinical and histopathological features of ITA and its relationship to IgG4‐related systemic disease. Methods: Two hundred fifty‐one patients underwent replacement of the ascending aorta. Retrospective review of all histological reports was done to identify noninfectious aortitis. Immunohistochemical analysis of resected specimens was performed in all cases. Results: We found 11 (4.4%) patients with noninfectious aortitis aged 52 to 79 years; nine of the patients were female. All patients underwent ascending aorta replacement. The 30‐day mortality was 0. During the follow‐up period (median 12 months) four patients died (two of them because of progression of aortic disease). None of the seven living patients developed any IgG4‐related diseases, and all had normal serum levels of IgG and IgG4. Conclusions: Surgical treatment of ITA has acceptable short‐ and mid‐term results. Because follow‐up serum levels of IgG and IgG4 were normal in survivors, postoperative corticosteroid therapy may not be indicated in patients in the absence of active vasculitis.     

Zoledronic acid to prevent bone loss in the first 6 months after renal transplantation

BACKGROUND: Bisphosphonates can prevent bone mineral density loss after renal transplantation, but their effect on trabecular mineralization and bone morphology, two key factors of bone stability, remains unknown. METHODS: In a 6-month, randomized, placebo-controlled study, 20 kidney transplant recipients received either 4 mg zoledronic acid or placebo twice within 3 months after engraftment. At transplantation and after 6 months, mean trabecular calcium concentration and trabecular morphometry were measured in bone biopsies. Bone mineral density (BMD) of the femoral neck and the lumbar spine were evaluated by dual-energy x-ray absorptiometry, and serum biochemical markers of bone metabolism were determined monthly. RESULTS: Trabecular calcium content increased significantly in the zoledronic acid group, but remained unchanged in the placebo group. BMD at femoral neck showed no change in the zoledronic acid group, but decreased in the placebo group. BMD of the lumbar spine was increased in the zoledronic acid group without change in the placebo group. High-turnover bone disease resolved similarly in both groups, as evidenced by a significant decrease of eroded bone surface, osteoclast and osteoblast surface. Serologic markers of bone formation and resorption were significantly lower in zoledronic acid-treated patients throughout the study. Kidney transplant function was stable after zoledronic acid therapy. CONCLUSIONS: Our results show that administration of zoledronic acid improves the calcium content of cancellous bone after kidney transplantation. The beneficial effect of bisphosphonate therapy is further evidenced by an increase of lumbar spine BMD, and stabilization of femur BMD.     

Self-reported risk factors related to the most frequent musculoskeletal complaints among Czech dentists

The purpose of the study was to describe the occurrence of the most common complaints related to MSDs in Czech dentists and to assess the risk factors affecting them. A questionnaire survey of 581 Czech dentists (the response rate 72.6%) was conducted in 2011. The questionnaire ascertained general information about the respondents, their work habits and environment along with the occurrence of musculoskeletal disorders. The respondents filled out the questionnaires during the educational events organized by the Czech Dental Chamber. At least mild difficulties associated with the motoric system were reported by 96.9% of the respondents, with 66.3% of respondents reporting moderate or major difficulties. Back and neck pain followed by shoulder pain and headache were the most common complaints in our sample. According to our data: age, gender, length of practice, a history of serious MSDs, the occurrence of MSDs in blood relatives, the perception of work as psychologically demanding, and especially a perceived moderate/bad general health were significantly associated with the four most common musculoskeletal complaints. Some of the factors were found as protective. This study suggests that MSDs represent a significant burden for Czech dentists and further research is needed to elucidate this issue.     

Asthma caused by potassium aluminium tetrafluoride: a case series

The objective of this study is to describe a case-series of potassium aluminium tetrafluoride (KAlF₄)-induced occupational asthma (OA) and/or occupational rhinitis (OR). The study involves five patients from a heat-exchanger production line who were examined (including specific inhalation challenge tests) for suspected OA and/or OR caused by a flux containing almost 100% KAlF₄ − with fluorides’ workplace air concentrations ranging between 1.7 and 2.8 mg/m³. No subject had a previous history of asthma. All five patients had a positive specific challenge test (three patients were diagnosed with OA alone, one with OR and one with both OR and OA). At the follow-up visit, after three years on average, all patients needed permanent corticosteroid therapy (four topical, one oral). After elimination from the exposure, only one of the observed subjects gave an indication of an improvement, two subjects stabilized and two worsened. Our case series focuses on the correlation between patients’ exposure to fluorides in air-conditioner production and the subsequent occurrence of OR/OA. Currently, it is uncertain whether these OR/OA were caused by hypersensitivity or irritation.     

The effects of repeated delivery of angiotensin II AT(1) receptor antisense on distinct vasoactive systems in Ren-2 transgenic rats: young vs. adult animals

Although Ren-2 transgenic rat (TGR) is defined as a model of angiotensin II-dependent hypertension, we studied whether the renin-angiotensin system (RAS) is really the main contributor to blood pressure (BP) elevation in hetero- and homozygous TGRs. Moreover, we examined whether repeated antisense (AS) therapy against AT(1) receptors would have a similar effect on the BP and the contribution of the principle vasoconstrictor/vasodilator systems to BP regulation in young and adult TGRs. From the age of 30 (young) and 100 (adult) days, rats were injected with AS for 40 days in 10-day intervals. After 10 and 40 days of AS therapy, the basal BP and acute BP responses to the sequential blockade of the RAS, sympathetic nervous (SNS) and nitric oxide systems were determined in conscious rats. The RAS system was the major system maintaining elevated BP in young homozygous animals, whereas there was an increasing contribution of the SNS in heterozygous TGR with age. The AS therapy in the young TGR had a transient BP-lowering effect that was associated with reduced cardiac hypertrophy; the AS therapy was most effective in young homozygous TGR, causing a substantial reduction of angiotensin-dependent vasoconstriction. In heterozygous rats, AS therapy at earlier stages was related to an inhibition of sympathetic vasoconstriction, whereas to RAS inhibition in established hypertension. In conclusion, repeated AS therapy had transient antihypertensive effects exclusively in young TGR. The contribution of the RAS to BP maintenance is highly important only in homozygous TGRs, whereas it is surpassed by SNS in heterozygous TGR.