Positively Charged Biodegradable Polymersomes with Structure Inherent Fluorescence as Artificial Organelles.

Polymersomes, nanosized polymeric vesicles, have attracted significant interest in the areas of artificial cells and nanomedicine. Given their size, their visualization via confocal microscopy techniques is often achieved through the physical incorporation of fluorescent dyes, which however present challenges due to potential leaching. A promising alternative is the incorporation of molecules with aggregation-induced emission (AIE) behavior that are capable of fluorescing exclusively in their assembled state. Here, we report on the use of AIE polymersomes as artificial organelles, which are capable of undertaking enzymatic reactions in vitro. The ability of our polymersome-based artificial organelles to provide additional functionality to living cells was evaluated by encapsulating catalytic enzymes such as a combination of glucose oxidase/horseradish peroxidase (GOx/HRP) or ß-galactosidase (ß-gal). Via the additional incorporation of a pyridinium functionality, not only the cellular uptake is improved at low concentrations but also our platform's potential to specifically target mitochondria expands.

Polymer Vesicles with Integrated Photothermal Responsiveness.

Functionalized polymer vesicles have been proven to be highly promising in biomedical applications due to their good biocompatibility, easy processability, and multifunctional responsive capacities. However, photothermal-responsive polymer vesicles triggered by near-infrared (NIR) light have not been widely reported until now. Herein, we propose a new strategy for designing NIR light-mediated photothermal polymer vesicles. A small molecule (PTA) with NIR-triggered photothermal features was synthesized by combining a D-D'-A-D'-D configuration framework with a molecular rotor function (TPE). The feasibility of the design strategy was demonstrated through density functional theory calculations. PTA moieties were introduced in the hydrophobic segment of a poly(ethylene glycol)-poly(trimethylene carbonate) block copolymer, of which the carbonate monomers were modified in the side chain with an active ester group. The amphiphilic block copolymers (PEG44-PTA2) were then used as building blocks for the self-assembly of photothermal-responsive polymer vesicles. The new class of functionalized polymer vesicles inherited the NIR-mediated high photothermal performance of the photothermal agent (PTA). After NIR laser irradiation for 10 min, the temperature of the PTA-Ps aqueous solution was raised to 56 °C. The photothermal properties and bilayer structure of PTA-Ps after laser irradiation were still intact, which demonstrated that they could be applied as a robust platform in photothermal therapy. Besides their photothermal performance, the loading capacity of PTA-Ps was investigated as well. Hydrophobic cargo (Cy7) and hydrophilic cargo (Sulfo-Cy5) were successfully encapsulated in the PTA-Ps. These properties make this new class of functionalized polymer vesicles an interesting platform for synergistic therapy in anticancer treatment.

Biodegradable Grubbs-Loaded Artificial Organelles for Endosomal Ring-Closing Metathesis.

The application of transition-metal catalysts in living cells presents a promising approach to facilitate reactions that otherwise would not occur in nature. However, the usage of metal complexes is often restricted by their limited biocompatibility, toxicity, and susceptibility to inactivation and loss of activity by the cell's defensive mechanisms. This is especially relevant for ruthenium-mediated reactions, such as ring-closing metathesis. In order to address these issues, we have incorporated the second-generation Hoveyda-Grubbs catalyst (HGII) into polymeric vesicles (polymersomes), which were composed of biodegradable poly(ethylene glycol)-b-poly(caprolactone-g-trimethylene carbonate) [PEG-b-P(CL-g-TMC)] block copolymers. The catalyst was either covalently or non-covalently introduced into the polymersome membrane. These polymersomes were able to act as artificial organelles that promote endosomal ring-closing metathesis for the intracellular generation of a fluorescent dye. This is the first example of the use of a polymersome-based artificial organelle with an active ruthenium catalyst for carbon-carbon bond formation.

Compartmentalized Intracellular Click Chemistry with Biodegradable Polymersomes.

Polymersome nanoreactors that can be employed as artificial organelles have gained much interest over the past decades. Such systems often include biological catalysts (i.e., enzymes) so that they can undertake chemical reactions in cellulo. Examples of nanoreactor artificial organelles that acquire metal catalysts in their structure are limited, and their application in living cells remains fairly restricted. In part, this shortfall is due to difficulties associated with constructing systems that maintain their stability in vitro, let alone the toxicity they impose on cells. This study demonstrates a biodegradable and biocompatible polymersome nanoreactor platform, which can be applied as an artificial organelle in living cells. The ability of the artificial organelles to covalently and non-covalently incorporate tris(triazolylmethyl)amine-Cu(I) complexes in their membrane is shown. Such artificial organelles are capable of effectively catalyzing a copper-catalyzed azide-alkyne cycloaddition intracellularly, without compromising the cells' integrity. The platform represents a step forward in the application of polymersome-based nanoreactors as artificial organelles.

Responsive Peptide Nanofibers with Theranostic and Prognostic Capacity.

Photodynamic therapy (PDT) is a highly promising therapeutic modality for cancer treatment. The development of stimuli-responsive photosensitizer nanomaterials overcomes certain limitations in clinical PDT. Herein, we report the rational design of a highly sensitive PEGylated photosensitizer-peptide nanofiber (termed PHHPEG 6 NF) that selectively aggregates in the acidic tumor and lysosomal microenvironment. These nanofibers exhibit acid-induced enhanced singlet oxygen generation, cellular uptake, and PDT efficacy in vitro , as well as fast tumor accumulation, long-term tumor imaging capacity and effective PDT in vivo . Moreover, based on the prolonged presence of the fluorescent signal at the tumor site, we demonstrate that PHHPEG 6 NFs can also be applied for prognostic monitoring of the efficacy of PDT in vivo , which would potentially guide cancer treatment. Therefore, these multifunctional PHHPEG 6 NFs allow control over the entire PDT process, from visualization of photosensitizer accumulation, via actual PDT to the assessment of the efficacy of the treatment.

Artificial Organelles: Towards Adding or Restoring Intracellular Activity.

Compartmentalization is one of the main characteristics that define living systems. Creating a physically separated microenvironment allows nature a better control over biological processes, as is clearly specified by the role of organelles in living cells. Inspired by this phenomenon, researchers have developed a range of different approaches to create artificial organelles: compartments with catalytic activity that add new function to living cells. In this review we will discuss three complementary lines of investigation. First, orthogonal chemistry approaches are discussed, which are based on the incorporation of catalytically active transition metal-containing nanoparticles in living cells. The second approach involves the use of premade hybrid nanoreactors, which show transient function when taken up by living cells. The third approach utilizes mostly genetic engineering methods to create bio-based structures that can be ultimately integrated with the cell's genome to make them constitutively active. The current state of the art and the scope and limitations of the field will be highlighted with selected examples from the three approaches.

Renal failure parathyroidectomy - Is pre-operative imaging worthwhile?

BACKGROUND: Tertiary hyperparathyroidism is a significant issue in renal failure patients and some require surgery to control their serum calcium. A number of imaging techniques are used to localise the position of the parathyroid glands prior to surgery. Currently, a combination of ultrasound and isotope preoperative localisation imaging is accepted as useful in parathyroid surgery for primary disease. However, the use of pre-operative imaging in parathyroid surgery in renal failure patients is uncertain. The role of pre-operative imaging of the parathyroid glands in patients with renal failure hyperparathyroidism was assessed with imaging outcomes compared to operative and pathological findings in two cohorts of patients undergoing parathyroid surgery - primary and tertiary. METHODS: All data were collected prospectively over a 10-year period (2003-2013) from the practice of a single surgeon. Patients were grouped into either primary hyperparathyroidism (49 patients) or tertiary hyperparathyroidism (41 patients). The majority, 63 of 90 (70%) patients, underwent both ultrasound (US) and isotope (MIBI) pre-operative imaging. Pre-operative imaging was correlated with operative and pathological findings. FINDINGS: Comparison of the results of the two groups using ordinal regression analysis confirmed these imaging techniques are significantly more accurate in primary than tertiary parathyroid surgery (p = 0.022). CONCLUSIONS: While accepted practice of pre-operative combined USS and MIBI imaging is essential in unilateral imaged-focused neck exploration for primary disease, these imaging techniques have a more limited use pre-operatively in renal failure parathyroidectomy.

Enzyme-Activatable Cell-Penetrating Peptides through a Minimal Side Chain Modification.

Activatable cell-penetrating peptides are of great interest in drug delivery because of their enhanced selectivity which can be controlled by the external stimuli that trigger their activation. The use of a specific enzymatic reaction to trigger uptake of an inert peptide offers a relevant targeting strategy because the activation process takes place in a short time and only in areas where the specific cell surface enzyme is present. To this aim, the lysine side chain of Tat peptides was modified with an enzyme-cleavable domain of minimal size. This yielded blocked Tat-peptides which were inactive but that could be activated by coincubation with the selected enzymes.

Carpal tunnel syndrome.

Carpal tunnel syndrome is one of the most common peripheral neuropathies. It affects mainly middle aged women. In the majority of patients the exact cause and pathogenesis of CTS is unclear. Although several occupations have been linked to increased incidence and prevalence of CTS the evidence is not clear. Occupational CTS is uncommon and it is essential to exclude all other causes particularly the intrinsic factors such as obesity before attributing it to occupation. The risk of CTS is high in occupations involving exposure to high pressure, high force, repetitive work, and vibrating tools. The classic symptoms of CTS include nocturnal pain associated with tingling and numbness in the distribution of median nerve in the hand. There are several physical examination tests that will help in the diagnosis of CTS but none of these tests are diagnostic on their own. The gold standard test is nerve conduction studies. However, they are also associated with false positive and false negative results. The diagnosis of CTS should be based on history, physical examination and results of electrophysiological studies. The patient with mild symptoms of CTS can be managed with conservative treatment, particularly local injection of steroids. However, in moderate to severe cases, surgery is the only treatment that provides cure. The basic principle of surgery is to increase the volume of the carpal tunnel by dividing transverse carpal ligament to release the pressure on the median nerve. Apart from early recovery and return to work there is no significant difference in terms of early and late complications and long-term pain relief between endoscopic and open carpal tunnel surgery.

Open carpal tunnel release--still a safe and effective operation.

BACKGROUND: Carpal tunnel syndrome is a common cause of neurological symptomatology. Surgical decompression remains the treatment of choice in patients not responding to conservative therapies. The aim of this study was to assess the effectiveness of standard open decompression by analysis of symptomatic and functional improvement and to assess whether a general surgeon can still perform this operation safely. PATIENTS AND METHODS: Patients undergoing standard open carpal tunnel release by a single general surgeon were recruited. A self-administered Boston questionnaire was used to assess symptom severity and functional status pre- and post-surgical intervention. RESULTS: Forty-seven patients (51 hands) underwent carpal tunnel release and 32 patients completed the questionnaire. 88% had a significant reduction in the symptom severity score, while improvement in function status score was achieved in 79% of patients. Mean symptom severity score improved from 3.41 points preoperatively to 1.85 (p < 0.0001) points at the last follow up examination, while the mean function status score improved from 2.73 to 1.99 points (p < 0.0001). Outcome was poor in six patients with slight worsening of either symptom or function status score. Three patients were treated conservatively for minor wound infection without long-term sequelae. DISCUSSION: Standard open carpal tunnel release still provides efficacious symptomatic relief with a low risk of associated complications when performed by a general surgeon.

Chronic pain after hernia surgery--an informed consent issue.

Chronic severe pain following inguinal hernia repair is a significant post-operative problem. Its exact cause and lack of evidence-based treatment path present problems in the effective management of this surgical complication. We retrospectively reviewed the records of patients diagnosed with chronic pain following open inguinal hernia repair between November 1995 and November 2000, who were under the care of the senior author. Over the five-year period, 146 patients underwent inguinal hernia repair. 88 (60%) had suture repair (darn & modified Bassini's) and 58 (40%) underwent a Lichtenstein mesh repair. Thirteen patients (9%), (3 in suture vs. 10 in mesh group, p = 0.004) developed chronic severe pain. Examination revealed maximal tenderness over the genitofemoral nerve (GF) distribution (n = 5), over the medial end of the scar (n = 3), over the pubic tubercle (n = 1) and in the ilioinguinal nerve distribution (n = 1) No abnormality was detected on clinical examination in the cases of three patients. Treatment involved GF nerve block (n = 5), local injection of Chirocaine and Methylprednisolone acetate into the medial end of the scar (n = 3), Chirocaine and Methylprednisolone acetate into the pubic tubercle (n = 1), ilioinguinal nerve block (n = 1), re-exploration with re-suturing of the mesh (n = 1), and Amitriptyline (n = 2). At a median follow up of 45 months (range: 24-87), 10 (77%) are completely pain free; two (15.4%) had mild pain and one patient still has significant persistent pain. To conclude, chronic severe pain occurred in nine percent of patients following primary open inguinal hernia repair. The majority of patients were successfully treated by therapeutic injection into the point of maximal tenderness.

Persistent behavioral effects following early life exposure to retinoic acid or valproic acid in zebrafish.

BACKGROUND: Moderate to severe dysregulation in retinoid signaling during early development is associated with a constellation of physical malformations and/or neural tube defects, including spina bifida. It is thought that more subtle dysregulation of this system, which might be achievable via dietary (i.e. hypervitaminosis A) or pharmacological (i.e. valproic acid) exposure in humans, will manifest on behavioral domains including sociability, without overt physical abnormalities. METHODS: During early life, zebrafish were exposed to low doses of two chemicals that disrupt retinoid signaling. From 0 to 5dpf, larvae were reared in aqueous solutions containing retinoic acid (0, 0.02, 0.2 or 2nM) or valproic acid (0, 0.5, 5.0 or 50µM). One cohort of zebrafish was assessed using a locomotor activity screen at 6-dpf; another was reared to adulthood and assessed using a neurobehavioral test battery (startle habituation, novel tank exploration, shoaling, and predator escape/avoidance). RESULTS: There was no significant increase in the incidence of physical malformation among exposed fish compared to controls. Both retinoic acid and valproic acid exposures during development disrupted larval activity with persisting behavioral alterations later in life, primarily manifesting as decreased social affiliation. CONCLUSIONS: Social behavior and some aspects of motor function were altered in exposed fish; the importance of examining emotional or psychological consequences of early life exposure to retinoid acting chemicals is discussed.

Increased granulocyte counts in recipients of plasma from leukapheresed rats: a dose response study.

Humoral factors are elaborated by animal and human donors during filtration leukapheresis. Plasma obtained from rats after leukapheresis (PPP) increases granulocyte yields when given to donors prior to leukapheresis. In our studies, it appears that (1) the effect of PPP is dose-related, and (2) the granulocytosis and the titer of neutrophil releasing activity are proportional to the duration of leukapheresis. On the basis of our findings, we recommend initiation of clinical studies using postleukapheresis plasma to improve granulocyte harvests and that a dose of 1.5 ml of PPP/kg appears to be a reasonable starting point.

Prucalopride, a systemic enterokinetic, for the treatment of constipation.

BACKGROUND: Laxatives are frequently ineffective in treating constipation. An alternative therapeutic approach is to target serotonin-4 receptors, which are involved in initiating peristalsis. AIM: In a double-blind, placebo-controlled trial, to assess the efficacy and safety of a systemically active serotonin-4 agonist, prucalopride. METHODS: Seventy-four women with constipation were stratified into slow or normal transit groups, and each group was randomized to receive either placebo or 1 mg prucalopride daily for 4 weeks. A bowel function diary was maintained. Whole-gut and orocaecal transit, visceral sensitivity, quality of life and psychological state were assessed before and after treatment. RESULTS: Prucalopride, not placebo, increased spontaneous stool frequency (P=0.008) and reduced time to first stool (P < 0.001). Prucalopride reduced the number of retained markers in all patients compared to placebo (P=0.004). Prucalopride reduced the mean number of retained markers in slow transit (P=0.069), but did not alter the marker count in normal transit (P=0.86). Orocaecal transit was accelerated by prucalopride, not placebo (P=0.004). Prucalopride, notplacebo, increased rectal sensitivity to distension (urge volume, P=0.01) and electrical stimulation (P=0.001). Prucalopride significantly improved several domains of the Short Form Health Status Survey and the disease-specific quality of life. Adverse effects were similar for prucalopride and placebo. CONCLUSIONS: Prucalopride improves symptoms, upper gut transit and gut sensitivity in constipated patients with both slow and normal transit. It improves transit in patients with slow transit. These changes are associated with improved well-being.

Control of mu opioid receptor expression by modification of cDNA 5'- and 3'-noncoding regions.

Removal of a 712 base pair (bp) sequence following the coding region of a human micro opioid receptor (hmuOR) cDNA unexpectedly increased expression of the receptor protein. A series of 3'-noncoding region deletion mutants revealed that at least three discrete regions following the stop codon influenced receptor expression levels. Deletion of the 205-bp 5'-noncoding region immediately preceding the Kozak sequence doubled receptor expression relative to wild type, and simultaneous deletion of 5'- and 3'-noncoding regions increased expression several fold. The hmuOR noncoding regions may participate in a regulatory mechanism that controls the number of cell surface receptors.

Surgeon and haematologist: a review of comprehensive care for patients with inherited bleeding disorders in Northern Ireland.

BACKGROUND: Management of patients with inherited bleeding disorders has improved since the introduction of Comprehensive Care Centres (CCC) in the United Kingdom (UK). In the event such patients need surgery, the aim of the multidisciplinary team is to facilitate outcomes as good as what would be expected in a non-bleeding disorder patient. A review of such comprehensive care was carried out in patients with inherited bleeding disorders when they needed surgery at Northern Ireland CCC. Aims of the study were to evaluate surgical morbidity and mortality in these patients. METHODS: All patients with inherited bleeding disorders who underwent non-orthopaedic surgery between 2008 and 2012 were identified from the CCC records within the Belfast Health and Social Care Trust (BHSCT) in Northern Ireland (NI) and their case records reviewed. RESULTS: 28 patients received elective and emergency surgery during this period. There was minimum morbidity and no mortality in this cohort. CONCLUSIONS: Surgery in patients with inherited bleeding disorders has become safe with the advent of multidisciplinary CCCs. Close communication between surgeon and haematologist is key in the successful management of these complex patients.

Randomised clinical trial: the efficacy of prucalopride in patients with chronic intestinal pseudo-obstruction--a double-blind, placebo-controlled, cross-over, multiple n = 1 study.

BACKGROUND: Chronic intestinal pseudo-obstruction is a disabling condition for which there are no established drug therapies. The condition is caused by a diverse range of intestinal myopathies and neuropathies. AIM: To assess the therapeutic efficacy of prucalopride, a selective high-affinity 5-HT(4) receptor agonist, we employed a multiple n = 1 study design. Each patient acted as his/her own control, each day counting as one treatment episode, allowing comparison of 168 days on each of active drug and placebo. METHODS: Double-blind, randomised, placebo-controlled, cross-over trial of four 12-week treatment periods, with 2-4 mg prucalopride or placebo daily. In each of the first and second 6 months there was a prucalopride and a placebo treatment. Patients with proven chronic intestinal pseudo-obstruction, including dilated gut, were included. Evaluation was by patient diary and global evaluation. RESULTS: Seven patients participated (mean 42 years, five female, median symptom duration 11 years). Three discontinued, two due to study length, and one on prucalopride due to unrelated malnutrition and bronchopneumonia. Four patients (three visceral myopathy and one visceral neuropathy) completed the study; prucalopride significantly improved pain in three of four patients, nausea in two, vomiting in one, bloating in four and analgesic intake. Bowel function was not changed substantially. CONCLUSIONS: n = 1 studies in rare conditions allow drug efficacy assessment. Prucalopride relieves symptoms in selected patients with chronic pseudo-obstruction.

Primary osteosarcoma of breast.

Primary osteosarcoma of breast is rare. The authors present a case of a 51-year-old female who was admitted with a large necrotising tumour involving the right breast. CT scan confirmed chest wall invasion along with a solitary lung metastasis. She underwent a primary mastectomy with chest wall reconstruction. Unfortunately 3 months later she developed local recurrence.