In vitro methods of assessing ocular biocompatibility using THP-1-derived macrophages

Macrophages play an important role in the elimination of infections, the removal of debris and in tissue repair after infection and trauma. In vitro models that assess ocular biomaterials for toxicity typically focus on the effects of these materials on epithelial or fibroblast cells. This investigation evaluated known ocular toxins deposited on model materials for their effects on the viability and activation of macrophages. THP-1-derived macrophages were cultured onto silicone films (used as a base biomaterial) deposited with chemical toxins (benzalkonium chloride (BAK), zinc diethyldithiocarbamate (ZDEC) and lipopolysaccharide (LPS)). Utilizing three fluorescent dyes calcein, ethidium homodimer-1 (EthD-1) and annexin V, the viability of macrophages attached to the biomaterial was determined using confocal microscopy. Propidium iodide (PI) staining and alamarBlue® (resazurin) reduction were used to assess cell death and metabolic activity. CD14, CD16, CD33, CD45, and CD54 expression of adherent macrophages, were also evaluated to detect LPS activation of macrophages using flow cytometry. The sensitivity of this test battery was demonstrated as significant toxicity from treated surfaces with ZDEC (0.001–0.01%), and BAK (0.001%–0.1%) was detected. Also, macrophage activation could be detected by measuring CD54 expression after exposure to adsorbed LPS. These in vitro methods will be helpful in determining the toxicity potential of new ocular biomaterials.     

Results of the systematic application of ventricular stimulation methods

This study was undertaken to test the validity of methods of evaluating ventricular tachycardia and in therapeutic surveillance. One hundred and thirty nine patients aged 16 to 84 years, with and without severe ventricular arrhythmias (ventricular tachycardia, VT, and fibrillation, VF) were divided into two groups after clinical, echocardiographic and 24 hour Holter investigations: Group I comprised 26 patients with a least one documented attack of VT or VF; Group II comprised 113 patients without these arrhythmias, who complained of dizziness, syncope, and/or their ECG showed a conduction defect, and so electrophysiological investigation was undertaken. A protocol of ventricular stimulation was undertaken in addition to the usual measurements of conduction times, comprising incremental ventricular stimulation from 100 to 200/min, single and paired extrastimulus in sinus rhythm and during ventricular pacing at rates of 100 and 150/min, the first extrastimulus being programmed 10 ms after the end of the ventricular effective refractory period. Excluding bundle to bundle reentry, the following results were obtained: In Group I: VT was triggered 16 times (61,5 p. 100), and in 4 of these cases VF occurred and required defibrillation. Ten patients had previous myocardial infarction; 5 patients had left ventricular dilatation. In 2 cases runs of 3 or 4 VES were recorded. No arrhythmia could be induced in 8 cases (30,8 p. 100); 5 of these patients had apparently normal hearts. In Group II: VT (greater than 5 VES) was triggered in 22 cases (19,5 p. 100) and in 4 cases this degenerated to VF requiring defibrillation. 11 patients had apparently normal hearts; 6 patients had left ventricular dilatation and 4 patients had previous myocardial infarction. 1 to 4 repetitive VES were observed in 67 cases (59,3 p. 100): the heart was judged to be normal in all patients except those with previous infarction. No correlation was established between the ability to induce VT and age, syncope, or ECG changes (especially bundle branch block). However, a correlation was found between the induction of VT and underlying cardiac disease and the method of induction of VT; in Group II, all episodes of VT were triggered by delivering paired ventricular extrastimuli on a background paced rhythm. These results show that repetitive ventricular responses can easily be triggered and that this has no pathological significance.(ABSTRACT TRUNCATED AT 400 WORDS)     

Fabry disease: focus on cardiac manifestations and molecular mechanisms

PATHOGENESIS: Fabry disease is an inherited lysosomal storage disorder caused by deficiency of the enzyme alpha-galactosidase A. The enzyme deficiency results in accumulation of glycosphingolipids in the lysosomes n nearly all cell types and tissues leading to a multisystem disease. MANIFESTATIONS include painful crisis, angiokeratomas, corneal dystrophy, and hypohydrosis. The severe renal, cerebrovascular, and cardiac involvement is predominantly responsible for premature mortality in Fabry patients. The disease is X-linked and manifests primarily in hemizygous males but also heterozygous females can be affected. CARDIAC INVOLVEMENT is frequent in Fabry disease. Patients develop hypertrophic cardiomyopathy, arrhythmias, conduction abnormalities, and valvular abnormalities. Although Fabry disease leads to a complex clinical syndrome, there are studies indicating that manifestations can be limited to the heart. The isolated cardiac variant of Fabry disease seems to be more common than previously thought: around 3-6% of male patients with left ventricular hypertrophy seem to suffer from this disease variant. ENZYME REPLACEMENT THERAPY: Recent advances in molecular biology and genetic engineering have enabled the development of enzyme replacement therapy in Fabry disease. Results from two independent therapy studies are indeed promising: Infusion of the enzyme preparation seems to be well tolerated and effective in catabolizing the lipid deposits. This enzyme replacement therapy could be one of the first examples for causal treatment of left ventricular hypertrophy. Therefore, early diagnosis of hypertrophy patients with the cardiac variant of Fabry disease is important.     

Detection of multiple viral and bacterial infections in acute exacerbation of chronic obstructive pulmonary disease: A pilot prospective study

Few studies have evaluated the contribution of multiple virus and bacterial infections in acute exacerbation of chronic obstructive pulmonary disease. This study estimated the burden of multiple viral and bacterial respiratory infections in moderate to very severe chronic obstructive pulmonary disease patients that were prospectively followed‐up during a 12‐month pilot study. Clinical data were collected monthly and sputum was collected at the time of each acute exacerbation event. Classical culture techniques for bacteria and multiplex polymerase chain reaction (PCR) and microarray detection assays were performed to identify viral and atypical bacterial pathogens in the sputum. Overall, 51 patients were included and 45 acute exacerbation events were investigated clinically and microbiologically. Among the 45 acute exacerbation events, 44% had evidence of viral infection involving human rhinovirus (HRV) and metapneumovirus (hMPV) in 20% and 18%, respectively. Intracellular bacteria were not found in sputum by PCR. Common bacterial pathogens were identified in 42% of acute exacerbation patients, most frequently Branhamella catarrhalis, Streptococcus pneumoniae and Haemophilus influenzae. Viral or virus and bacteria co‐infections were detected in 27% of acute exacerbation events (n = 12) with HRV and hMPV involved in 92% of cases. Patients with co‐infections did not present greater clinical severity scores at exacerbation and more recurrence of acute exacerbation events at 3 and 6 months than those with single infections (P > 0.4). These results suggest that HRV and hMPV may be contributors or cofactors of AECOPD. These findings indicate that viral or virus and bacterial co‐infections do not impact significantly on the clinical severity of acute exacerbation of chronic obstructive pulmonary disease and recurrence at 3 and 6 months. J. Med. Virol. 85:866–873, 2013. © 2013 Wiley Periodicals, Inc.