Non-biodegradable Particles Research Articles

The effects of microplastics in oceans and marine environment on public health – a mini-review

Plastic’s versatility is one reason why production or use has not decreased over the years. The production of plastic globally was 359 million metric tons as of 2018, and this number increased by 3.5% in 2019. Microplastics, which are tiny particles of various types and forms of plastic, can be found in cosmetics, fabrics, car parts, machinery, footwear,products packaging, polythene bags and so on. Over time, these particles, through the process of wear and tear of these various plastic products, indiscriminate disposal, runoffs, and erosion, find their way into water bodies from rivers and streams into larger water bodies like seas and oceans. These tiny non-biodegradable particles find their way into living organisms carrying along with them other harmful chemical contaminants. This study reviews the effects that microplastics found in marine environments have on public health in general. It covers the types and sources of microplastics and the various ways in which microplastics have affected human health and different aquatic species in the marine environment. The review showed all pointers of microplastics present in the environment to have negative impacts on the ecosystem. Certain research gaps are pointed out, like the integration of researchinto policies to help improve the environment and the standardization of dedicated procedures and methods of reporting microplastic pollution. Suggestions were made for possible solutions like the reduction of plastic use for product packaging, provision of biodegradable and eco-friendly materials as substitutes, and general public awareness on the harm of microplastic pollution in the immediate environement.

Evaluation and HPLC characterisation of a new herbal ointment for the treatment of full-thickness burns in rats

ObjectiveBurn injuries are among the most common accidental health problems worldwide, frequently leading to health and socio-economic challenges. Despite this, no standard protocol for managing burn injuries can overcome the adverse effects of currently used drugs. The present study sets out to develop and evaluate the efficacy of new herbal ointments in providing synergistic anti-inflammatory, antimicrobial, antioxidant, and cell-proliferating activities. It also investigates the high-performance liquid chromatography (HPLC) characterisation of these new herbal ointments. MethodThree different concentrations of the new herbal ointment, which incorporates extracts of Matricaria aurea flower heads, arial parts of Calendula tripterocarpa, Rosmarinus officinalis leaves, Alkanna tinctoria roots, and myrrh were developed and evaluated. Ointments designed to promote burn-wound healing were prepared and compared with β-sitosterol ointment and silver sulfadiazine cream, as a commercial standards. ResultsAccording to statistical and histopathological analyses and visual inspections, the new herbal formulas showed faster wound healing, more tolerability, and less toxicity than the commercial standards. ConclusionThe new herbal ointments, developed in our study, have shown promising results. The formula offers mechanical protection without any release of non-biodegradable particles. It maintains the optimum moisture and pH of the skin, while minimising scar-tissue formation. These advantages, in addition to availability, low costs, and easy handling, may support the use of this new herbal formula as an effective and safe alternative treatment, designed to promote the healing of burn injuries.

Durasphere® EXP: a non-biodegradable agent for treatment of primary Vesico-Ureteral reflux in children

ABSTRACTIntroduction:Durasphere® EXP (DEXP) is a compound of biocompatible and non--biodegradable particles of zirconium oxide covered with pyrolytic carbon. The aim of this study is to evaluate the durability of off-label use of DEXP in the treatment of primary vesicoureteral reflux in children.Materials and Methods:Patients who underwent subureteric injection of DEXP for the correction of primary VUR were retrospectively reviewed. Patients aged >18 years as well as those who had grade-I or -V VUR, anatomic abnormalities (duplicated system, hutch diverticulum), neurogenic bladder or treatment refractory voiding dysfunction were excluded. Radiologic success was defined as the resolution of VUR at the 3rd month control. Success was radiographically evaluated at the end of the first year.Results:Thirty-eight patients (9 boys, 29 girls; mean age, 6.3±2.7 years) formed the study cohort. Forty-six renal units received DEXP (grade II: 22; grade III: 18; grade IV: 6). Mean volume per ureteric orifice to obtain the mound was 0.70±0.16mL. First con- trol VCUG was done after 3 months in all patients. After the first VCUG, 6 patients had VUR recurrence. Short-term radiologic success of DEXP was 84.2%. Rate of radiologic success at the end of the first year was 69.4% (25/32). Lower age (p:0.006) and lower amount of injected material (p:0.05) were associated with higher success rates at the end of 1 year.Conclusion:This is the first study to assess the outcomes of DEXP for treatment of primary VUR in children. After 1 year of follow-up, DEXP had a 69.4% success rate.

PH-responsive magnesium- and carbonate-substituted apatite nano-crystals for efficient and cell-targeted delivery of transgenes

The short half-lives due to the enzymatic degradation in blood, the lack of tissue targetability and the incapability to passively diffuse across the plasma membrane and smoothly traffic across the harsh intracelluar environment are the major shortcomings for nucleic acid-based potential therapeutics, such as recombinant plasmid and antisense oligonucleotides or small interferring RNA (siRNA). Plasmid DNA containing a gene of interest could have immense impact as a promising therapeutic drug for treating genetic as well as acquired human diseases at the molecular level with high level of efficacy and precision. Thus both viral and non-viral synthetic vectors have been developed in the past decades to address the aforementioned challenges of naked DNA. While in the viral particles plasmid DNA is integrated into the viral genome, in most non-viral cases the DNA being anionic in nature is electrostatically associated with a cationic lipid or polymer forming lipoplex or polyplex, respectively, or a cationized inorganic gold, silica or iron oxide particle. Due to the potential immunogenicity and carcinogenicity issues with the viral particles, non-viral vectors have drawn much more attention for the clinical evaluation. However, the main concern of using non-biodegradable particles, specially the inorganic ones, is the adverse effects owing to their long term interactions with body components. We have recently developed biodegradable pH-sensitive inorganic nanoparticles of Mg/CaPi and carbonate apatite for efficient transgene delivery to primary, cancer and embryonic stem cells, by virtue of their high affinity binding with the DNA, ability to contact the cell membrane by ionic or ligand-receptor interactions and fast dissolution kinectis in endosomal acidic pH facilitating release of the DNA from the dissolving particles and also from the endosomes.

Acute Toxicity of Intravenously Administered Microfabricated Silicon Dioxide Drug Delivery Particles in Mice

Microfabricated particles with nanosized features may serve an important role in the next generation of drug delivery vehicles. Microfabrication (micro-electromechanical systems) technologies offer the promise of both structural elements (e.g., pores, reservoirs) and electromechanical features (e.g., timers, valves, actuators) built into a single particle. In order to serve as carriers to deliver drugs to systemic sites of action, such as tumors, the particles must be safe to administer intravenously. An acute safety study was performed in a mouse model, using intravenous injection of solid silicon dioxide particles created to simulate the size and shape of potential targeted drug delivery vehicles. Two-micron thick, square and circular, parallelepiped-shaped particles were produced with varying sizes of 2 microm, 5 microm and 10 microm using microfabrication techniques and injected into groups of mice (six mice per group) over a range of doses. End-points included acute lethality, clinical signs of toxicity and weight loss. Sections of major organs were sampled for histological examination. At dose levels of 1 x 10(8) particles per mouse, circular particles of 2 microm and 5 microm showed no signs of acute toxicity. Similar results were obtained with the 2 microm and 5 microm square silicon dioxide particles; however, 14-day necropsy indicates fewer 5 microm circular particles in the lung than 5 microm square particles, indicating that the shape of the particles may impact on safety. Acute lethality was observed for 10 microm particles; none of the mice injected with the 10 microm particles survived except at very low dose levels of 6 x 10(5) particles per mouse. Solid silicon particles greater than 5 microm in their largest dimension are cleared in the lungs and are not safe for intravenous delivery. Particles of 2-5 microm in size do not lodge predominantly in the lung and do not cause acute toxicity, but accumulate in organs such as the liver and spleen. Possible chronic toxicities associated with organ uptake of such non-biodegradable particles have yet to be addressed.

Clinical evaluation of patients with temporomandibular joint implants

Purpose: An undetermined number of patients with temporomandibular joint (TMJ) symptoms have been treated with intra-articular disc implants composed of Teflon ethylene/propylene or Teflon polytetrafluoroethylene and aluminum oxide (Proplast-Teflon; Vitek, Houston, TX). These implants have shown the potential to fragment in situ resulting in nonbiodegradable particles that stimulate a giant cell reaction and lead to degeneration of local structures, pain, and limitation of mandibular opening. We examined the possible relationship between TMJ implants and persistent pain, responses to sensory stimuli, quality of life, and systemic immune dysfunction. Patients and Methods: This case series (32 patients) were referred from university-based orofacial pain centers and private practices from across the United States. Laboratory and clinical assessments evaluated orofacial pain symptoms, neurologic function, clinical signs and symptoms of rheumatologic disease, physical function, systemic measures of immune function, and behavioral measures. Results: We found that TMJ implant patients appeared to have altered sensitivity to sensory stimuli, a higher number of tender points with a diagnosis of fibromyalgia, increased self-report of chemical sensitivity, higher psychologic distress and significantly lower functional ability. Systemic illness or autoimmune disease was not evident in this series of TMJ implant patients. Conclusions: Significant problems were noted on clinical assessment of TMJ implant patients. This is a US government work. There are no restrictions on its use. J Oral Maxillofac Surg 60:1389-1399, 2002

Surface modification of nanoparticles by PEO/PPO block copolymers to minimize interactions with blood components and prolong blood circulation in rats

The biological fate of injected foreign particles is believed to be closely related to their interactions with blood plasma proteins and cells. In order to verify this correlation, we have quantitatively measured protein adsorption and blood retention profiles in rats by using model polystyrene latex nanoparticles. The in vitro interactions of these non-biodegradable particles with plasma proteins and whole blood can be altered by modifying their surfaces with a family of amphiphilic polymeric surfactants, PEO/PPO Pluronic or Tetronic block copolymers. Protein adsorption was measured by several techniques, including photon correlation spectroscopy, centrifugation, high performance liquid chromatography and field-flow fractionation. Pluronic F108 and Tetronic 908 and 1508 copolymers (with PEO terminal block MW PEO > 5000, PPO middle block MW PPO > 3000, and HLB values > 24) were shown to be the most effective surface modifiers in reducing adsorption of plasma proteins on the particles. Minimum interaction of coated particles with whole blood was also observed by optical microscopy. The blood circulation half-life of the particles injected in rats was increased from 20 min to 13 h when the latex particles (75 nm) were precoated with these block copolymers. These results suggest that nanoparticles designed for use as injectable drugs or drug carriers should display similar surface characteristics provided by such amphiphilic surface modifiers.

Induction of trypsinogen secretion in herring larvae (Clupea harengus)

Mechanisms initiating trypsinogen secretion were studied in laboratory reared herring larvae (Clupea harengus L.) exposed to physical and chemical stimuli. Pancreatic secretion of trypsinogen was quantified for each stimulus type as the increase above pre-stimulus level of intestinal trypsin content. Larval prey types were: nauplii, copepodites or adult Acartia tonsa, small polystyrene spheres (diameter 94 μm), small (diameter 79 μm) or large (diameter 170 μm) polystyrene-latex spheres. Intestinal trypsin content can be expressed as a function of two variables: meal size and content of pancreatic trypsinogen. Trypsinogen secretion increases with different prey items in the order: small spheres, nauplii and copepodites. Larvae which eat large spheres secrete more enzyme than if fed small spheres but trypsinogen secretion is similar in fish larvae fed copepodites and large spheres. The fact that the size of non-biodegradable particles exerts a major control over trypsinogen secretion suggests neural — as opposed to chemically mediated — initiation of secretion. A cephalic phase of secretory stimulation could not be demonstrated during swallowing of copepods or exposure for 2 to 3 h to compounds which leak from live copepodites. As cephalic and gastric phases of secretory stimulation are absent, initiation of trypsinogen secretion must take place in the intestine. Larval herring retain trypsin in the intestine. Ca. 4.5 h after a meal, 3/4 of the enzyme is located in the intestinal fluid, presumably available for hydrolysis of subsequent meals, and the high proportion (ca. 25%) of the pancreatic trypsinogen content which is secreted for copepodite prey may thus not be energetically wasteful for the larvae.