Low plasma magnesium concentration and future abdominal aortic calcifications in moderate chronic kidney disease

BACKGROUND: Higher plasma magnesium concentrations are associated with reduced cardiovascular disease risk in chronic kidney disease (CKD) patients. The importance of plasma magnesium concentration for vascular calcification in earlier stages of CKD remains underexplored. This study investigated whether plasma magnesium is a determinant for the presence and severity of vascular calcification in moderate CKD. METHODS: Retrospective analysis was performed using abdominal aortic calcification (AAC) scores in 280 patients with stage 3 and 4 CKD enrolled in the MASTERPLAN trial. Lateral abdominal X-ray was used to evaluate AAC. Plasma magnesium concentration were measured over time. A zero-inflated Poisson model determined the association between plasma magnesium concentration and AAC. RESULTS: 79 out of 280 patients did not have AAC, and in patients with AAC the median calcification score was 3.5 (interquartile range: 0.0-8.6). The mean plasma magnesium concentration was 0.76 ± 0.10 mmol/L at baseline. A 0.1 mmol/L higher plasma magnesium concentration was associated with lower AAC of 0.07 point (95% CI -0.28 - 0.14). A 0.1 mmol/L higher plasma magnesium lowered the odds of detecting any AAC by 30% (OR = 0.63; 95% CI 0.29-1.37). After 1 year and 4 years (at time of X-ray) of follow-up this association was attenuated (OR = 0.93; 95% CI 0.61-1.43 and 0.93; 95% CI 0.60-1.45, respectively). None of these associations reached statistical significance. CONCLUSIONS: Plasma magnesium concentration at baseline is not associated with the risk for future AAC. Interventions increasing magnesium to avoid vascular calcification may have greatest potential in early CKD stages prior to onset of vascular calcification

Mare and foal survival and subsequent fertility of mares treated for uterine torsion

Reasons for performing study: Previous surveys have reported that mare and foal survival after correction of uterine torsion (UT) varies from 60 to 84% and from 30 to 54%, respectively. Furthermore, resolution via a standing ¿ank laparotomy (SFL) has been associated with better foal, but not mare, survival. Objectives: To compare the success of SFL with other correction methods (e.g. midline or ¿ank laparotomy under general anaesthesia; correction per vaginam). Study design: Retrospective analysis of clinical records. Methods: Data on correction technique, stage of gestation, degree of rotation, survival and subsequent fertility for 189 mares treated for UT at 3 equine referral hospitals in The Netherlands during 1987–2007 were analysed. Results: Mean stage of gestation at diagnosis was 283 days (range 153–369 days), with the majority of UTs (77.5%) occurring before Day 320 of gestation. After correction of UT, 90.5% of mares and 82.3% of foals survived to hospital discharge, between 3 and 39 days later, and to foaling. Multivariable logistic regression indicated that correction method and stage of gestation at UT affected survival of foals and mares. For foals, survival was 88.7% after SFL compared with 35.0% after other methods (P = 0.001). When UT occurred a

Single-stage reconstruction of third-degree perineal lacerations in horses under general anesthesia : Utrecht repair method

OBJECTIVE: To describe perioperative management, surgical procedure, and outcome in mares with third-degree perineal lacerations (TDPL) treated with a single-stage repair, the Utrecht repair method (URM). STUDY DESIGN: Retrospective study. ANIMALS: Twenty mares with TDPL. METHODS: Medical records of mares with TDPL reconstructed with a URM were reviewed for perioperative management; surgical outcome; and postoperative fertility, athletic performance, and complications. RESULTS: Mares ranged in age from 3.5 to 11 years. Long-term follow-up was available for 13 mares. Mean duration of follow-up was 9 years (median, 9.5; range, 2-215 months (17.9 years)). Standardized perioperative fasting and postoperative refeeding protocols were used. Only five mares received supportive gastric medication. Reconstruction of the rectovestibular shelf was successful in 18 of 20 mares. Two of 20 mares developed a small rectovestibular fistula after the initial repair, which was successfully repaired with a second surgery. Other postoperative complications were observed in 13 mares and consisted of mild postanesthetic myositis, facial nerve paralysis, esophageal obstruction, rectal obstipation, partial perineal dehiscence, and rectal or vestibular wind-sucking. Six of seven mares that were subsequently bred became pregnant. One mare was successfully used for embryo recovery, and five of six mares foaled without recurrence of a TDPL. Nine of 13 mares were used for riding at various levels. CONCLUSION: The alternative single-stage reconstruction for TDPL was successful in 18 of 20 mares after a single surgery. No major complications related directly to the technique were noted. CLINICAL SIGNIFICANCE: The URM is a valid alternative surgical technique for repairing TDPL in mares

Magnesium to prevent kidney disease-associated vascular calcification: crystal clear?

Vascular calcification is a prognostic marker for cardiovascular mortality in chronic kidney disease (CKD) patients. In these patients, magnesium balance is disturbed, mainly due to limited ultrafiltration of this mineral, changes in dietary intake and the use of diuretics. Observational studies in dialysis patients report that a higher blood magnesium concentration is associated with reduced risk to develop vascular calcification. Magnesium prevents osteogenic vascular smooth muscle cell transdifferentiation in in vitro and in vivo models. In addition, recent studies show that magnesium prevents calciprotein particle maturation, which may be the mechanism underlying the anti-calcification properties of magnesium. Magnesium is an essential protective factor in the calcification milieu, which helps to restore the mineral-buffering system that is overwhelmed by phosphate in CKD patients. The recognition that magnesium is a modifier of calciprotein particle maturation and mineralization of the extracellular matrix renders it a promising novel clinical tool to treat vascular calcification in CKD. Consequently, the optimal serum magnesium concentration for patients with CKD may be higher than in the general population

Mare and foal survival and subsequent fertility of mares treated for uterine torsion

REASONS FOR PERFORMING STUDY: Previous surveys have reported mare and foal survival after correction of uterine torsion varies from 60-84% and 30-54%, respectively. Furthermore, resolution via a standing flank laparotomy (SFL) has been associated with better foal, but not mare, survival. OBJECTIVES: To compare the success of SFL with other correction methods (e.g. midline or flank laparotomy under general anaesthesia; correction per vaginam). STUDY DESIGN: Retrospective analysis of clinical records. METHODS: Data on correction technique, stage of gestation, degree of rotation, survival and subsequent fertility for 189 mares treated for uterine torsion (UT) at 3 equine referral hospitals in the Netherlands during 1987-2007 were analysed. RESULTS: Mean stage of gestation at diagnosis was 283 days (range 153-369) with the majority of UTs (77.5%) occurring before Day 320 of gestation. After UT correction, 90.5% of mares and 82.3% of foals survived to hospital discharge, between 3 and 39 days later, and to foaling. Multivariable logistic regression indicated that correction method and stage of gestation at UT affected survival of foals and mares. For foals, survival was 88.7% after SFL compared to 35.0% after other methods (P = 0.001). When UT occurred at <320 days, 90.6% of foals survived, compared to 56.1% at ≥320 days (P = 0.007). For mare survival, an interaction between stage of gestation and correction method was detected (P = 0.02), with higher survival after SFL (97.1%) than other methods (50.0%) at <320 days of gestation (P<0.01). When UT occurred at ≥320 days, mare survival did not differ between techniques (76.0% vs. 68.8; P = 0.6). Of 123 mares that were bred again, 93.5% became pregnant; fertility did not differ between mares treated by SFL (93.9%) and other techniques (87.5%; P = 0.9). CONCLUSIONS: SFL is the surgical technique of choice for resolving uncomplicated (i.e. no co-existing gastrointestinal lesions) equine UT except when the stage of gestation exceeds 320 days

Management and outcome of fractures of the distal phalanx: A retrospective study of 285 horses with a long term outcome in 223 cases

A multicentre study of 285 cases was performed to enhance the management of distal phalangeal fractures on the basis of clinical evidence. The outcome after treatment was available for 223 of the cases. Horses with a non-articular type I fracture had a better prognosis (91.7%) for return to original or expected level of use than horses with an articular type II or III fracture (69.6% and 74.1%, respectively). The prognosis for types IV and V fractures was fair (57.7% and 57.1%, respectively) and for type VI good (80%). Horses with a hindlimb fracture had a significantly greater chance of a successful outcome. No significant association between age or time to start treatment and success rate was noted. The best treatment option for types I-III fractures was a conservative approach (box rest). Type IV fractures were best treated by arthroscopic removal of the fragment. Immobilisation of the hoof did not seem to influence outcome. Radiological findings and clinical healing were not accurately correlated and the re-commencement of training should be based on clinical rather than radiological findings. Complete osseous union of the fracture was not essential for a successful return to athletic activity

Calciprotein particle inhibition explains magnesiummediated protection against vascular calcification

Background: Phosphate (Pi) toxicity is a strong determinant of vascular calcification development in chronic kidney disease (CKD). Magnesium (Mg2+) may improve cardiovascular risk via vascular calcification. The mechanism by which Mg2+ counteracts vascular calcification remains incompletely described. Here we investigated the effects of Mg2+ on Pi and secondary crystalline calciprotein particles (CPP2)-induced calcification and crystal maturation. Methods: Vascular smooth muscle cells (VSMCs) were treated with high Pi or CPP2 and supplemented with Mg2+ to study cellular calcification. The effect of Mg2+ on CPP maturation, morphology and composition was studied by medium absorbance, electron microscopy and energy dispersive spectroscopy. To translate our findings to CKD patients, the effects of Mg2+ on calcification propensity (T50) were measured in sera from CKD patients and healthy controls. Results: Mg2+ supplementation prevented Pi-induced calcification in VSMCs. Mg2+ dose-dependently delayed the maturation of primary CPP1 to CPP2 in vitro. Mg2+ did not prevent calcification and associated gene and protein expression when added to already formed CPP2. Confirmatory experiments in human serum demonstrated that the addition of 0.2 mmol/L Mg2+ increased T50 from healthy controls by 51 ± 15 min (P < 0.05) and CKD patients by 44 ± 13 min (P < 0.05). Each further 0.2 mmol/L addition of Mg2+ led to further increases in both groups. Conclusions: Our results demonstrate that crystalline CPP2 mediates Pi-induced calcification in VSMCs. In vitro, Mg2+ delays crystalline CPP2 formation and thereby prevents Pi-induced calcification