Coexistent primary open-angle glaucoma and cataract: Preliminary analysis of treatment by cataract surgery and the iStent trabecular micro-bypass stent

INTRODUCTION: Reducing intraocular pressure (IOP) is the only proven treatment modality for reducing the risk of glaucomatous progression. In this study, we evaluated the safety and efficacy of a new tool in IOP reduction, implanted with cataract surgery: the Glaukos iStent trabecular micro-bypass stent. METHODS: This was a prospective, 24-month, uncontrolled, non-randomised, multicentre study. Subjects with uncontrolled primary open-angle glaucoma (including pseudoexfoliation and pigmentary) and a cataract underwent clear cornea phacoemulsification cataract extraction with ab-interno gonioscopically guided implantation of the study stent. Subjects who had completed at least 6 months of follow-up were included in this interim analysis (n=47). RESULTS: At baseline, mean (+/-standard deviation) IOP was 21.5+/-3.7 mmHg, and subjects were taking a mean of 1.5+/-0.7 ocular hypotensive medications. Six months after implantation of the study stent the mean IOP was 15.8+/- 3.0 mmHg, a mean IOP reduction of 5.7+/-3.8 mmHg (25.4%, P<0.001). The mean number of patient medications after 6 months was 0.5+/-0.8 medications, a mean decrease of 1.0+/-0.8 medications (66.7%, P<0.001). Most subjects (70%) were able to discontinue all glaucoma medications. There were no complications traditionally associated with filtering surgery, and no serious adverse events were reported. CONCLUSION: In this interim analysis of subjects with glaucoma and cataracts, this novel stent implantation in subjects undergoing cataract surgery represents a new surgical approach to provide clinically significant decreases in IOP and drug burden.     

Treatment of Postmenopausal Osteoporosis

Osteoporosis is a skeletal disease characterized by low bone mass and microarchitectural deterioration with a resulting increase in bone fragility and hence susceptibility to fracture. Calcium and vitamin D are the most commonly used therapies for osteoporosis, although their efficacy in osteoporotic fracture prevention remains uncertain. Biphosphonates are the most frequently prescribed medication for treatment of osteoporosis and are often considered as first-line therapy for the treatment of osteoporosis. Currently, hormone replacement therapy is only approved by the Food and Drug Administration (FDA) for short-term treatment of severe postmenopausal symptoms with the lowest dose used for the shortest time. In view of its lack of effect on the prevention of nonvertebral fractures, the use of raloxifene should be limited to women with spinal osteoporosis. Most experts agree that it is preferable to treat osteoporosis with a more potent agent than calcitonin and manage the pain separately. Currently, the FDA recommends the use of parathyroid hormone for treatment of osteoporosis for a maximum of 2 years because of the concern of development of osteosarcoma. Drs. Gupta and Aronow have no real or apparent conflicts of interest relating to the subject under discussion.     

Cystatin C and beta2-microglobulin: markers of glomerular filtration in critically ill children

Introduction  

Parameters allowing regular evaluation of renal function in a paediatric intensive care unit (PICU) are not optimal. The aim of the present study was to analyse the utility of serum cystatin C and beta2-microglobulin (B2M) in detecting decreased glomerular filtration rate in critically ill children.     

Static jaw collimation settings to minimize radiation dose to normal brain tissue during stereotactic radiosurgery

At the University of Arkansas for Medical Sciences (UAMS) intracranial stereotactic radiosurgery (SRS) is performed by using a linear accelerator with an add-on micromultileaf collimator (mMLC). In our clinical setting, static jaws are automatically adapted to the furthest edge of the mMLC-defined segments with 2-mm (X jaw) and 5-mm (Y jaw) margin and the same jaw values are applied for all beam angles in the treatment planning system. This additional field gap between the static jaws and the mMLC allows additional radiation dose to normal brain tissue. Because a radiosurgery procedure consists of a single high dose to the planning target volume (PTV), reduction of unnecessary dose to normal brain tissue near the PTV is important, particularly for pediatric patients whose brains are still developing or when a critical organ, such as the optic chiasm, is near the PTV. The purpose of this study was to minimize dose to normal brain tissue by allowing minimal static jaw margin around the mMLC-defined fields and different static jaw values for each beam angle or arc. Dose output factors were measured with various static jaw margins and the results were compared with calculated doses in the treatment planning system. Ten patient plans were randomly selected and recalculated with zero static jaw margins without changing other parameters. Changes of PTV coverage, mean dose to predefined normal brain tissue volume adjacent to PTV, and monitor units were compared. It was found that the dose output percentage difference varied from 4.9–1.3% for the maximum static jaw opening vs. static jaw with zero margins. The mean dose to normal brain tissue at risk adjacent to the PTV was reduced by an average of 1.9%, with negligible PTV coverage loss. This dose reduction strategy may be meaningful in terms of late effects of radiation, particularly in pediatric patients. This study generated clinical knowledge and tools to consistently minimize dose to normal brain tissue.     

Vogt-Koyanagi-Harada syndrome and mesenteric ischemia: A case report

Vogt-Koyanagi-Harada (VKH) disease is a rare inflammatory ocular disorder that is characterized by bilateral granulomatous panuveitis, neuropathy, and aseptic meningitis, along with various extraocular manifestations. VKH disease has been reported to be associated with various immune disorders. In this report, a case of VKH disease is presented that is associated with mesenteric vascular disease and intestinal necrosis, with an emphasis on the fact that this is the first case documented in the literature of both diseases occurring simultaneously.     

Effect of stress-induced reversible ischemia on serum concentrations of ischemia-modified albumin,natriuretic peptides and placental growth factor

Summary Objective There is controversy whether new biomarkers are able to identify myocardial ischemia in the absence of myonecrosis. Method We measured NT-pro BNP, NT-pro ANP, ischemia-modified albumin (IMA) and placental growth factor (PlGF) in patients undergoing nuclear stress testing for suspected ischemic heart disease. A thallium scan was used for detection of reversible myocardial ischemia and cardiac troponin T (cTnT) for exclusion of stress-induced myonecrosis. Of 195 patients, 24 with reversible and 62 with no perfusion defect were included in the analysis. Plasma levels were measured before, 18 min and 4 h after stress testing. Results Of the 86 patients, 52 received an exercise stress and 34 dipyridamol. New myonecrosis indicated by cTnT could be excluded in all patients. Plasma levels of NT-pro BNP and NT-pro ANP before testing were significantly higher in patients who later developed reversible perfusion defects (NT-pro BNP 139.00 (58.25/367.01) pg/mL vs 327.45 (120.50/972.85) pg/mL, p < 0.05; NT-pro ANP 732.5 (470.0/ 1220.0) pg/mL vs 1470.0 (694.0/ 1910.0) pg/mL, p < 0.05). Plasma levels of NT-pro BNP, NT-pro ANP and PIGF did not change significantly after stress testing, IMA levels rose significantly after 4 h in patients with and without reversible perfusion defects. Conclusion The elevation of NTpro BNP and NT-pro ANP at baseline may represent the cumulative effect of repeated bouts of myocardial ischemia. A single brief episode of provoced ischemia does not cause a significant increase of the measured biomarkers beside from IMA after exercise stress test potentially indicating skeletal muscle ischemia.     

Simvastatin decreases nitric oxide overproduction and reverts the impaired vascular responsiveness induced by endotoxic shock in rats

Lipopolysaccharides (LPS) can be used to induce experimental endotoxic shock, which is characterized by a significant decrease in mean arterial pressure (MAP) and a decreased vasoconstrictor response that have been attributed to excessive nitric oxide production. Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase), in addition to lowering serum cholesterol levels, exert many pleiotropic effects, including anti-inflammatory action. In the present study, we investigated the effect of simvastatin, an HMG-CoA reductase inhibitor, on the production of nitric oxide and the cardiovascular response to LPS. Male Wistar rats were pretreated with different doses of simvastatin (10, 20, 40, and 80 mg/kg, i.p.) or saline 20 min before i.v. injection of LPS (1.5 mg/kg) or saline (control). MAP was continuously recorded and nitrate plasma concentration was determined during the 6-h experimental session at 1-h intervals. The pressor response to phenylephrine (1 microg/kg) was evaluated before and 6 h after LPS administration. In the LPS-treated group, there was a time-dependent increase in nitrate plasma concentration (P<0.001), and this response was decreased in simvastatin pretreated rats (P<0.001). We also observed that LPS decreased the pressor response to phenylephrine (P<0.001), an effect that was reverted by simvastatin pretreatment (P<0.05). However, simvastatin did not modify the decrease of MAP induced by LPS. We concluded that simvastatin decreases nitrate plasma concentration in response to LPS and recovers vascular responsiveness during an experimental endotoxic shock. These data suggest the potential use of HMG-CoA reductase inhibitors as a coadjuvant in the treatment of septic shock.