Factors determining phage stability/activity: challenges in practical phage application

Introduction: Phages consist of nucleic acids and proteins that may lose their activity under different physico-chemical conditions. The production process of phage formulations may decrease phage infectivity. Ingredients present in the preparation may influence phage particles, although preparation and storage conditions may also cause variations in phage titer. Significant factors are the manner of phage application, the patient’s immune system status, the type of medication being taken, and diet.

Areas covered: We discuss factors determining phage activity and stability, which is relevant for the preparation and application of phage formulations with the highest therapeutic efficacy. Our article should be helpful for more insightful implementation of clinical trials, which could pave the way for successful phage therapy.

Expert opinion: The number of naturally occurring phages is practically unlimited and phages vary in their susceptibility to external factors. Modern methods offer engineering techniques which should lead to enhanced precision in phage delivery and anti-bacterial activity. Recent data suggesting that phages may also be used in treating nonbacterial infections as well as anti-inflammatory and immunomodulatory agents add further weight to such studies. It may be anticipated that different phage activities could have varying susceptibility to factors determining their actions.     

P2Y13 and P2X7 receptors modulate mechanically induced adenosine triphosphate release from mast cells

Subcutaneous mast cells (MCs) are vulnerable to mechanical stimulation from external environment. Thus, MCs immune function could be modulated by their mechanosensitivity. This property has been identified as the trigger mechanism of needling acupuncture, a traditional oriental therapy. Previously we have demonstrated the release of adenosine triphosphate (ATP), a stress-responsive signalling molecule, from mechanical-perturbed MCs. The current work explores its underlying mechanisms. We noticed that propagation of intracellular free Ca²⁺ occurred among HMC-1 cells in response to 50% hypotonic shock. Additionally, amplifying cascade of ATP-induced ATP release was observed in RBL-2H3 cells stimulated by medium displacement, which could be mimicked by exogenous ATP (exoATP). Secondary ATP liberation induced by low level (50 nmol/L) of exoATP was reduced by inhibiting ecto-ATPase-dependent ADP production with ARL67156, or blocking P2 receptors with suramin or PPADS, or with specific P2Y₁₃ receptor antagonist MRS2211, or siRNA. Secondary ATP release induced by higher dose (200 μmol/L) of exoATP, sufficient to stimulate P2X₇ receptor, was attenuated by suramin, PPADS or specific P2X₇ receptor antagonist BBG, or siRNA. Finally, RT-PCR confirmed mRNA expression of P2Y₁₃ and P2X₇ in RBL-2H3 cells. Additionally, such secondary ATP release was attenuated by DPCPX, specific antagonist of adenosine A1 receptor, but not by MRS2179, specific inhibitor of P2Y₁ receptor. In summary, mechanosensitive ATP release from MCs is facilitated by paracrine/autocrine stimulation of P2Y₁₃ and P2X₇ receptors. This multi-receptor combination could mediate transmission of information from a local site to distal areas, enabling communication with multiple surrounding cells to coordinate and synchronize their function.     

The Value of Electrocardiographic Abnormalities in the Prognosis of Pulmonary Embolism: A Consensus Paper

Electrocardiographic (ECG) abnormalities in the setting of acute pulmonary embolism (PE) are being increasingly characterized and mounting evidence suggests that ECG plays a valuable role in prognostication for PE. We review the historical 21‐point ECG prognostic score for the severity of PE and examine the updated evidence surrounding the utility of ECG abnormalities in prognostication for severity of acute PE. We performed a literature search of MEDLINE, EMBASE, and PubMed up to February 2015. Article titles and abstracts were screened, and articles were included if they were observational studies that used a surface 12‐lead ECG as the instrument for measurement, a diagnosis of PE was confirmed by imaging, arteriography or autopsy, and analysis of prognostic outcomes was performed. Thirty‐six articles met our inclusion criteria. We review the prognostic value of ECG abnormalities included in the 21‐point ECG score, including new evidence that has arisen since the time of its publication. We also discuss the potential prognostic value of several ECG abnormalities with newly identified prognostic value in the setting of acute PE.     

An ultrasonographic monitoring of skin condition in patients receiving radiotherapy for head and neck cancers

Radiodermatitis is one of the commonest side effects of radiotherapy. They are usually assessed by semi‐quantitative clinical scores, which are not validated and may be subject to inter‐observer variability. A few previous studies suggested that high‐frequency ultrasonography (HF‐USG) is useful in the assessment of the acute phase of radiation dermatitis in breast cancer patients. (a) To monitor skin changes by HF‐USG during the course of radiotherapy due to head and neck cancers, and (b) to determine whether there is any connection between skin sonograms and the skin scoring criteria. This prospective, observational study includes patients diagnosed with head and neck cancers, treated with radiotherapy or concomitant chemoradiation. The final analysis includes six patients. In every patient, the HF‐USG as well as dermatological assessment (target lesion score—TLS and CACE v. 4.0) were performed 4×: before, in the middle, day after, and 3 months after radiotherapy. There were significant differences between non‐irradiated skin thickness and thickness of skin with clinically obvious radiodermatitis (TLS grade 1‐4; P < .0001), as well as between irradiated, unchanged skin thickness (TLS grade 0) and thickness of skin with clinically obvious radiodermatitis (TLS grade 1‐4; P = .0002). There was no significant difference between non‐irradiated and irradiated, unchanged skin thickness (TLS grade 0; P = .9318). In four patients, we demonstrated subepidermal low echogenic band (SLEB). HF‐USG can be useful tool to noninvasive and objective assessment of skin changes during radiotherapy.     

Zapobieganie zakażeniom meningokokowym – jak stosować obecnie dostępne szczepionki

Authors have presented the current recommendations for the prevention of meningococcal infections. The epidemiological situation in Poland has been described and the use of currently available meningococcal vaccines has been discussed. The chemoprophylaxis for close contacts of all people with invasive meningococcal disease has been also presented.     

Decreased Hypoxia-Inducible Factor-1α in Gastrocnemius Muscle in Rats with Chronic Kidney Disease

Background/Aims: Hypoxia-inducible factor (HIF)-1α is responsible for increased expression of genes engaged in angiogenesis. Our previous study indicated capillary rarefaction and atrophy of glycolytic fibers, mainly in locomotor muscles of uremic animals. Perhaps these changes are secondary to disturbances of HIF-1α in skeletal muscles. Methods: Expression of HIF-1α at mRNA and protein levels, as well as mRNA of vascular endothelial growth factor A (VEGF-A), vascular endothelial growth factor receptor (VEGFR)-1, VEGFR-2, endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS), in gastrocnemius muscle (MG) and longissimus thoracic muscle (ML) were measured by RT-PCR and Western blot. Rats were randomized to subtotal nephrectomy (CKD5/6), uninephrectomy (CKD1/2) or sham operation (controls). Results: For CKD5/6 versus controls, mRNA levels for HIF-1α, VEGF-A, VEGFR-1 and VEGFR-2 were significantly reduced only in MG, while eNOS was significantly decreased and iNOS was significantly increased only in ML. Western blot analysis indicated significantly increased HIF-1α protein levels in MG and ML from CKD1/2 animals versus controls, whereas in the CKD5/6 group, the level of HIF-1α protein decreased significantly in MG and increased significantly in ML versus controls and CKD1/2. Conclusion: The reduced expression of HIF-1α mRNA and protein in locomotor muscle from CKD5/6 animals may be involved in the pathogenesis of uremic myopathy. Increased expression of iNOS in the postural muscles may act as a protective factor through HIF-1α stabilization.     

A single weekly dose of imatinib is sufficient to induce and maintain remission of chronic eosinophilic leukaemia in FIP1L1-PDGFRA-expressing patients

Hypereosinophilic syndrome (HES) is defined as chronic, unexplained hypereosinophilia with organ involvement. A subset of HES patients presents an interstitial deletion in chromosome 4q12, which leads to the expression of an imatinib-responsive fusion gene, FIP1L1-PDGFRA. These patients are diagnosed as chronic eosinophilic leukaemia (CEL). We treated seven CEL and HES patients, six of which expressed FIP1L1-PDGFRA , with imatinib using initial daily doses ranging from 100 to 400 mg. In a remission maintenance phase, the patients were treated with imatinib once weekly. All imatinib-treated patients achieved a complete haematological remission (CHR), and five of the six patients with FIP1L1-PDGFRA expression exhibited molecular remission. The decreased imatinib doses were as follows: 200 mg/week in three patients, 100 mg/week in two patients and 100 mg/d in the remaining two patients. For remission maintenance, imatinib doses were set at 100 mg/week in five patients and 200 mg/week in two patients. At a median follow-up of 30 months all patients remained in CHR and FIP1L1-PDGFRA expression was undetectable in five of the six FIP1L1-PDGFRA -expressing patients. These data suggest that a single weekly dose of imatinib is sufficient to maintain remission in FIP1L1-PDGFRA - positive CEL patients.