Role of endoscopy in patients with diverticular disease

Acute diverticulitis occurs in 10-25% of patients with diverticulosis. Colonoscopy is advised 6 weeks after an attack of acute diverticulitis in order to completely evaluate the colonic lumen and exclude a potential malignancy. We conducted several studies aimed to evaluate the feasibility and safety of early colonoscopy in patients with acute diverticulitis. Consecutive patients hospitalized for acute diverticulitis were included. In the first phase of the study, patients with adjacent peri-diverticular air/fluid on CT were excluded. In the second phase of the study, we included patients with peri-diverticular air/fluid on CT as well. During the first phase of the study, 39 patients underwent uneventful colonoscopy. During the second phase of the study, 40 patients underwent colonoscopy and 1 of 6 patients with peri-diverticular air had perforation of her sigmoid colon. Two patients had a more protracted course and were clearly those who benefited most from the early colonoscopy. Based on our study, we concluded that early colonoscopy in acute diverticulitis is feasible. It should be reserved either for all patients with no air adjacent to diverticuli on CT or just for those with a more protracted course. In the third phase, a prospective randomized study was conducted on patients with acute diverticulitis with no peri-diverticular air. Such patients were randomized into those who underwent early colonoscopy and those who underwent colonoscopy 6 weeks later. Eighty-three patients were included in both groups and in none has a significant lesion been identified (except polyps). It seems therefore that the current abdominal CT with its excellent resolution is enough to exclude colonic cancer. Colonoscopy should be reserved only for patients with a protracted unresolved course of acute diverticulitis.     

Clopidogrel tapering as a strategy to attenuate platelet rebound phenomenon in patients with bare-metal stents

Early clustering of adverse cardiovascular events after abrupt cessation of clopidogrel has been reported in patients with acute coronary syndromes. A platelet rebound phenomenon may contribute to this increased thrombotic risk and a gradual drug tapering may attenuate this proposed platelet effect. Accordingly, we aimed to assess the effect of clopidogrel tapering on platelet reactivity. Twenty patients who underwent elective percutaneous coronary interventions with bare metal stents receiving 3 months of clopidogrel therapy (75 mg daily) were randomized to either of two discontinuation strategies: (1) Off group–abrupt drug cessation or (2) Tapering group–receiving clopidogrel 75 mg every other day for 4 weeks duration. Light transmission aggregometry, induced by ADP (5 and 10 μM) and collagen, was measured at four time-points (at baseline and 2, 4 and 6 weeks after randomization). In the off group, there was an early rise in platelet reactivity at 2 weeks after abrupt drug cessation compared to baseline, as measured by ADP 5 μmol/l (39.6 ± 2.8 vs. 67.9 ± 6.0, P < 0.001). The tapering regimen suppressed this rebound platelet aggregation by ADP 5 μmol/l at 2 weeks (P = 0.001) and 4 weeks (P = 0.001). Similar results were found with ADP 10 μmol/l and collagen agonists. Abrupt cessation of clopidogrel results in an early rise in platelet aggregability in patients with BMS that is attenuated by a tapering regimen. Clopidogrel administration every other day may achieve similar levels of platelet inhibition as full dose therapy. Further investigations evaluating clopidogrel tapering strategies and their potential clinical impact are warranted.     

Evaluation and Management of the Premenopausal Woman with Low BMD

Interpretation of bone mineral density (BMD) results in premenopausal women is particularly challenging, since the relationship between BMD and fracture risk is not the same as for postmenopausal women. In most cases, Z scores rather than T scores should be used to define “low BMD” in premenopausal women. The finding of low BMD in a premenopausal woman should prompt thorough evaluation for secondary causes of bone loss. If a secondary cause is found, management should focus on treatment of this condition. In a few cases where the secondary cause cannot be eliminated, treatment with a bone active agent to prevent bone loss should be considered. In women with no fractures and no known secondary cause, low BMD is associated with microarchitectural defects similar to young women with fractures; however, no longitudinal data are available to allow use of BMD to predict fracture risk. BMD is likely to be stable in these women with isolated low BMD, and pharmacologic therapy is rarely necessary. Assessment of markers of bone turnover and follow-up bone density measurements can help to identify those with an ongoing process of bone loss that may indicate a higher risk for fracture, and possible need for pharmacologic intervention.     

Implications of pars planitis-associated cystoid macular edema on visual outcome and management in children

Graefe's Archive for Clinical and Experimental Ophthalmology - Pars planitis is a commonly observed type of pediatric uveitis. The aim of this study was to evaluate the implications of pars...     

Protective effect of high density lipoprotein associated paraoxonase. Inhibition of the biological activity of minimally oxidized low density lipoprotein.

Our group has previously demonstrated that oxidized phospholipids in mildly oxidized LDL (MM-LDL) produced by oxidation with lipoxygenase, iron, or cocultures of artery wall cells increase monocyte-endothelial interactions and this sequence of events is blocked by HDL. To obtain further insight into the mechanism by which HDL abolishes the activity of MM-LDL we investigated the effect of the HDL-associated ester hydrolase paraoxonase (PON). Treatment of MM-LDL with purified PON significantly reduced the ability of MM-LDL to induce monocyte-endothelial interactions. Inactivation of PON by pretreating HDL with heat or EDTA reduced the ability of HDL to inhibit LDL modification. HPLC analysis of phospholipids isolated from MM-LDL before and after treatment with purified PON showed that the 270 nm absorbance of phospholipids was decreased, while no effect was observed on 235 nm absorbance. Oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (Ox-PAPC) and specific fractions of Ox-PAPC isolated by HPLC induced the same monocyte-endothelial interactions as did MM-LDL. Biologically active and inactive HPLC fractions of Ox-PAPC were compared by fast atom bombardment-mass spectrometry which revealed that active fractions possessed ions with a mass to charge [correction of change] ratio greater than native PAPC by multiples of 16 D suggesting the addition of 3 and 4 oxygen atoms to PAPC. Comparison of Ox-PAPC by fast atom bombardment-mass spectrometry before and after PON treatment showed that PON destroyed these multi-oxygenated molecules found in biologically active fractions of Ox-PAPC. These results suggest that PON in HDL may protect against the induction of inflammatory responses in artery wall cells by destroying biologically active lipids in mildly oxidized LDL.     

The relationship between peritubular capillary protein concentration and fluid reabsorption by the renal proximal tubule

The relationship between peritubular capillary protein concentration and rate of sodium reabsorption by the rat proximal tubule was examined using free-flow recollection micropuncture techniques. Tubule fluid-to-plasma inulin ratios were measured before, during, and at successive intervals after brief (15-25 sec) intra-aortic injections (at the level of the renal artery) of colloid-free, isoncotic, and hyperoncotic solutions. Arterial hematocrit and protein concentrations were measured simultaneously in these rats. In other rats, total protein concentration of peritubular capillary blood plasma was determined before, during, and after these same infusions with a newly described submicroliter fiber-optic colorimeter.In the 15-25 sec interval necessary to infuse 2 ml of these test solutions, fractional and absolute sodium reabsorption varied directly with peritubular capillary colloid osmotic pressure, declining during infusion of colloid-free solutions, increasing during hyperoncotic infusions, and remaining unchanged during isoncotic infusions.In the subsequent 20-min interval after intra-aortic injection of these test solutions, capillary protein concentration remained at (isoncotic infusions) or returned to (colloid-free and hyperoncotic fluids) control values. Whereas reabsorption after colloid-free solutions returned to base line levels in parallel with the return in capillary protein concentration, after colloid infusions (which resulted in continued expansion of extracellular fluid volume), a progressive decline in reabsorption was observed.These results afford strong evidence that peritubular capillary colloid osmotic pressure is one important determinant of proximal sodium reabsorption. Nevertheless it is apparent that mechanisms other than or in addition to this must be invoked to explain the delayed inhibition of reabsorption that accompanies expansion of extracellular fluid volume by colloid solutions.     

Inverse correlation between coronary and retinal blood flows in patients with normal coronary arteries and slow coronary blood flow

Background

The “Slow Coronary Flow” (SCF) phenomenon in the presence of angiographically normal coronaries is attributed to microvascular and endothelial dysfunction. The microcirculation can be non-invasively assessed by measuring retinal blood flow velocity.The aim of the present study was to evaluate the efficacy of the “Retinal Functional Imager” (RFI) device as a noninvasive method of diagnosing patients with slow coronary flow.

Methods

Coronary blood flow velocity assessed by corrected TIMI Frame Count and retinal arterioles blood flow assessed by RFI were measured in 28 consecutive patients with normal coronary arteries. The patients were divided into 2 groups: a slow coronary flow (SCF) and a normal coronary flow (NCF) groups.

Results

Inverse correlation was found between retinal and coronary blood flows so that higher retinal arterial flow velocity was observed in the SCF group (3.8 ± 1.1 mm/s vs. 2.9 ± 0.61 mm/s, respectively, p = 0.022). RFI provided 73% sensitivity and 77% specificity for diagnosing SCF using ROC analysis. Additionally, patients with SCF had higher values of serum LDL cholesterol (104.7 ± 18.93 mg/dl vs. 81.55 ± 14.62 mg/dl in NCF, p = 0.005), Glucose (96.9 ± 23.0 mg/dl vs. 83.55 ± 9.7 mg/dl in NCF, p = 0.024), and lower percentage of statin consumption (40.0% vs. 76.9% in NCF, p = 0.049).

Conclusions

Slow coronary blood flow can be non-invasively diagnosed with Retinal Functional Imager. Patients with normal coronary arteries and slow coronary blood flow have high retinal arteriolar blood flow. Early non-invasive diagnosis of SCF might help detect individuals who are at higher risk to develop coronary atherosclerosis, and to provide them with early preventive measures.