Contribution of the Vertebral Posterior Elements in Anterior–Posterior DXA Spine Scans in Young Subjects

Because DXA is a projection technique, anterior–posterior (AP) measurements of the spine include the posterior elements and the vertebral body. This may be a disadvantage because the posterior elements likely contribute little to vertebral fracture resistance. This study used QCT to quantify the impact of the posterior elements in DXA AP spine measures. We examined 574 subjects (294 females and 280 males), age 6–25 yr, with DXA and QCT. QCT measures were calculated for the cancellous bone region and for the vertebral body including and excluding the posterior elements. DXA data were analyzed for the entire L₃ vertebra and for a 10‐mm slice corresponding to the QCT scan region. BMC and BMD were determined and compared using Pearson's correlation. The posterior elements accounted for 51.4 ± 4.2% of the total BMC, with a significant difference between males (49.9 ± 4.0%) and females (52.8 ± 3.9%, p < 0.001). This percentage increased with age in younger subjects of both sexes (p < 0.001) but was relatively consistent after age 17 for males and 16 for females (p > 0.10). DXA areal BMD and QCT volumetric BMD correlated strongly for the whole vertebra including the posterior elements (R = 0.83), with BMC measures showing a stronger relationship (R = 0.93). Relationships were weaker when excluding the posterior elements. We conclude that DXA BMC provides a measure of bone that is most consistent with QCT and that the contribution of the posterior elements is consistent in young subjects after sexual maturity.     

Daily profile of circulating C-type natriuretic peptide in pre-ascitic cirrhosis and in normal subjects: relationship with renal function

OBJECTIVE: To investigate whether the C-type natriuretic peptide (CNP) has a role in the regulation of fluid and sodium homeostasis in normal subjects and in pre-ascitic cirrhotic patients. MATERIAL AND METHODS: The daily profile of CNP plasma levels was assessed by serial measurements (0700 h, 0900 h, 1800 h, 2300 h) in 10 pre-ascitic cirrhotic outpatients (age 56+/-4 years) and in 10 age-matched healthy controls (54+/-2 years) on a normal sodium diet (150 mmol/day) while carrying on their usual activities (mobile from 0700 h to 2200 h), after an equilibration period of 5 days. Daily diuresis and natriuresis were also monitored. RESULTS: Mean daily CNP was comparable in cirrhotic and healthy subjects (3.64+/-0.32 versus 3.20+/-0.20 pg/ml; p=0.139); CNP concentration showed a tendency towards a circadian fluctuation in healthy subjects (p=0.053) but not in patients (p=0.171). Mean daily CNP concentration significantly correlated with 24-h natriuresis (r=0.709; p=0.022) and urine volume (r=0.745; p=0.013) in patients but not in healthy subjects. CONCLUSIONS: CNP plasma levels appear to play a role in the water-sodium balance regulation in patients with pre-ascitic cirrhosis.     

Statins and fenofibrate affect skeletal muscle chloride conductance in rats by differently impairing ClC-1 channel regulation and expression

Background and purpose:

Statins and fibrates can produce mild to life-threatening skeletal muscle damage. Resting chloride channel conductance (gCl), carried by the ClC-1 channel, is reduced in muscles of rats chronically treated with fluvastatin, atorvastatin or fenofibrate, along with increased resting cytosolic calcium in statin-treated rats. A high gCl, controlled by the Ca²⁺-dependent protein kinase C (PKC), maintains sarcolemma electrical stability and its reduction alters muscle function. Here, we investigated how statins and fenofibrate impaired gCl.

Experimental approach:

In rats treated with fluvastatin, atorvastatin or fenofibrate, we examined the involvement of PKC in gCl reduction by the two intracellular microelectrodes technique and ClC-1 mRNA level by quantitative real time-polymerase chain reaction. Direct drug effects were tested by patch clamp analysis on human ClC-1 channels expressed in human embryonic kidney (HEK) 293 cells.

Key results:

Chelerythrine, a PKC inhibitor, applied in vitro on muscle dissected from atorvastatin-treated rats fully restored gCl, suggesting the involvement of this enzyme in statin action. Chelerythrine partially restored gCl in muscles from fluvastatin-treated rats but not in those from fenofibrate-treated rats, implying additional mechanisms for gCl impairment. Accordingly, a decrease of ClC-1 channel mRNA was found in both fluvastatin-and fenofibrate-treated rat muscles. Fenofibric acid, the in vivo metabolite of fenofibrate, but not fluvastatin, rapidly reduced chloride currents in HEK 293 cells.

Conclusions and implications:

Our data suggest multiple mechanisms underlie the effect of statins and fenofibrate on ClC-1 channel conductance. While statins promote Ca²⁺-mediated PKC activation, fenofibrate directly inhibits ClC-1 channels and both fluvastatin and fenofibrate impair expression of mRNA for ClC-1.     

A word of caution: Early failure of Magmaris® bioresorbable stent after pulmonary artery stenting

Bioresorbable scaffolds (BRS) have been advocated as the fourth revolution in interventional cardiology medical devices with promising technology to improve the treatment of coronary artery disease with an event-free future. We describe the first reported use and early collapse of the Magmaris® Resorbable Magnesium Scaffold (RMS) stent (BIOTRONIK AG, Switzerland) to relieve left pulmonary artery severe stenosis in a newborn after the Norwood procedure. The stent collapse was detected 2 weeks after implantation and urgently treated with a balloon-expandable stent. This complication raises the alarm about the need to keep implanted RMS under scrutiny. The possibility of faster scaffold resorption in small babies or lack of sufficient radial force of RMS to resist acute vessel recoil has led to ineffective relief of branch pulmonary artery stenosis and failure to enable a safe short-term bridge to Stage II palliation.     

Obtaining accurate patient‐specific perioperative anaesthetic costs in orthopaedic anaesthesia

□ The aim of the study was to obtain perioperative patient‐specific costs associated with orthopaedic anaesthesia □ A prospective observational study design was used to determine fixed, semi‐fixed, and variable costs □ The preliminary results of the first 60 patients reports a mean total perioperative anaesthetic cost of £291 (SD: £103.9, median: £278.09, IQR: £219.3–£369.5) □ Fixed and semi‐fixed costs are a major cost component of anaesthesia; variable costs account for only 12 per cent of total cost □ The results of this study will be used in an economic evaluation examining the use of different anaesthetic techniques in orthopaedics     

Chronic daily headache with migrainous features due to papilledema-negative idiopathic intracranial hypertension

Patients with the syndrome of chronic daily headache often report migrainous symptoms and consequently are diagnosed as having a primary headache syndrome. We report two cases of idiopathic intracranial hypertension causing chronic daily headache with migrainous features in the absence of associated papilledema.     

Immunoreactive human chorionic gonadotropin and its free beta subunit in serum and ascites of patients with malignant tumors.

Human chorionic gonadotropin (hCG) is a clinically relevant marker of trophoblastic and nontrophoblastic malignancies. In the present studies, in addition to determining serum hCG, we investigated the presence and properties of hCG immunoreactivity in ascites of patients with nontrophoblastic malignant tumors and, for comparison, in ascites caused by cirrhotic liver disease. Total hCG immunoreactivity [hCG (+hCG-beta)] was found to be elevated above the reference value (greater than 5 IU/liter) in the serum of 2 of 20 patients with cirrhosis and 11 of 20 patients with malignant tumors. For comparison, in ascites, hCG (+hCG-beta) concentrations were frequently higher than in the corresponding serum samples and exceeded 10 IU/liter in 0 of 20 cirrhotic samples and in 16 of 20 malignant samples. In order to elucidate the nature of the hCG immunoreactive material, all samples were then assessed by immunoradiometric assays specific for the intact hCG molecule (holo-hCG) and the free hCG-beta subunit, respectively. In the holo-hCG assay, elevated values were detected in 0 of 20 (0 of 20) cirrhotic ascites (serum) samples and 0 of 20 (1 of 20) malignant ascites (serum) samples. In the free hCG-beta assay, on the other hand, no positive results were obtained in the ascites or serum of 20 patients with liver cirrhosis; however, 8 of 20 serum samples and 16 of 20 ascites samples derived from tumor patients were positive. In accord with the immunological data, gel chromatographical studies of malignant ascites revealed the abundance of free hCG-beta subunit rather than that of holo-hCG. In contrast to malignancy-related ascites, in ascites of patients receiving hCG injections for treatment of infertility, holo-hCG was more abundant than free hCG-beta immunoreactivity. Incubation experiments of purified holo-hCG in ascites for 24 h at -20, 20, or 37 degrees C showed no substantial dissociation of the hCG molecule and release of free hCG-beta immunoreactivity, thus arguing against production of free hCG-beta by degradation of holo-hCG and in favor of its tumor-related secretion. In conclusion, hCG-beta immunoreactivity is frequently elevated in malignancy-related ascites and appears to be related to the presence of free beta subunit of hCG rather than that of the intact hCG molecule. Interestingly, hCG-beta determination in ascites proved to be clearly superior to serum measurement in discriminating between tumor and cirrhosis.(ABSTRACT TRUNCATED AT 400 WORDS)