Wound dressings functionalized with silver nanoparticles: promises and pitfalls

Infections are the main reason why most people die from burns and diabetic wounds. The clinical challenge for treating wound infections through traditional antibiotics has been growing steadily and has now reached a critical status requiring a paradigm shift for improved chronic wound care. The US Centers for Disease Control have predicted more deaths from antimicrobial-resistant bacteria than from all types of cancers combined by 2050. Thus, the development of new wound dressing materials that do not rely on antibiotics is of paramount importance. Currently, incorporating nanoparticles into scaffolds represents a new concept of 'nanoparticle dressing' which has gained considerable attention for wound healing. Silver nanoparticles (Ag-NPs) have been categorized as metal-based nanoparticles and are intriguing materials for wound healing because of their excellent antimicrobial properties. Ag-NPs embedded in wound dressing polymers promote wound healing and control microorganism growth. However, there have been several recent disadvantages of using Ag-NPs to fight infections, such as bacterial resistance. This review highlights the therapeutic approaches of using wound dressings functionalized with Ag-NPs and their potential role in revolutionizing wound healing. Moreover, the physiology of the skin and wounds is discussed to place the use of Ag-NPs in wound care into perspective.

Autoclave-assisted synthesis of AgNPs in Z. officinale extract and assessment of their cytotoxicity, antibacterial and antioxidant activities

In this study, the authors synthesised silver nanoparticles (AgNPs) using autoclave as a simple, unique and eco-friendly approach. The effect of Zingiber officinale extract was evaluated as a reducing and stabiliser agent. According to transmission electron microscopy results, the AgNPs were in the spherical shape with a particle size of ∼17 nm. The biomedical properties of AgNPs as antibacterial agents and free radical scavenging activity were estimated. Synthesised AgNPs showed significant 1,1-diphenyl-2-picryl-hydrazyl free radical scavenging. Strong bactericidal activity was shown by the AgNPs on Gram-positive and Gram-negative bacteria. A maximum inhibition zone of ∼14 mm was obtained for epidermidis at a concentration of 60 μg/ml for sample fabricated at 24 h. The AgNPs also showed a significant cytotoxic effect against MCF-7 breast cancer cell lines with an half maximal inhibitory concentration value of 62 μg/ml in 24 h by the MTT assay. It could be concluded that Z. officinale extract can be used effectively in the production of potential antioxidant and antimicrobial AgNPs for commercial application.

Biomedical applications of chitosan electrospun nanofibers as a green polymer - Review

This review outlines new developments in the biomedical applications of environmentally friendly ('green') chitosan and chitosan-blend electrospun nanofibers. In recent years, research in functionalized nanofibers has contributed to the development of new drug delivery systems and improved scaffolds for regenerative medicine, which is currently one of the most rapidly growing fields in all of the life sciences. Chitosan is a biopolymer with non-toxic, antibacterial, biodegradable and biocompatible properties. Due to these properties, they are widely applied for biomedical applications such as drug delivery, tissue engineering scaffolds, wound dressings, and antibacterial coatings. Electrospinning is a novel technique for chitosan nanofiber fabrication. These nanofibers can be used in unique applications in biomedical fields due to their high surface area and porosity. The present work reviews recent reports on the biomedical applications of chitosan-based nanofibers in detail.

Chitosan/(polyvinyl alcohol)/zeolite electrospun composite nanofibrous membrane for adsorption of Cr6+, Fe3+ and Ni2

In this study, chitosan/polyvinyl alcohol (PVA)/zeolite nanofibrous composite membrane was fabricated via electrospinning. First, crude chitosan was hydrolyzed with NaOH for 24h. Afterward, hydrolyzed chitosan solution was blended with aqueous PVA solution in different weight ratios. Morphological analysis of chitosan/PVA electrospun nanofiber showed a defect-free nanofiber material with 50:50 weight ratio of chitosan/PVA. Subsequently, 1wt.% of zeolite was added to this blended solution of 50:50 chitosan/PVA. The resulting nanofiber was characterized with field emission scanning electron microscopy, X-Ray diffraction, Fourier transform infrared spectroscopy, swelling test, and adsorption test. Fine, bead-free nanofiber with homogeneous nanofiber was electrospun. The resulting membrane was stable in distilled water, acidic, and basic media in 20 days. Moreover, the adsorption ability of nanofibrous membrane was studied over Cr (VI), Fe (III), and Ni (II) ions using Langmuir isotherm. Kinetic parameters were estimated using the Lagergren first-order, pseudo-second-order, and intraparticle diffusion kinetic models. Kinetic study showed that adsorption rate was high. However, the resulting nanofiber membrane showed less adsorption capacity at high concentration. The adsorption capacity of nanofiber was unaltered after five recycling runs, which indicated the reusability of chitosan/PVA/zeolite nanofibrous membrane. Therefore, chitosan/PVA/zeolite nanofiber can be a useful material for water treatment at moderate concentration of heavy metals.

Synthesis of chitosan/polyvinyl alcohol/zeolite composite for removal of methyl orange, Congo red and chromium(VI) by flocculation/adsorption

A chitosan/polyvinyl alcohol (PVA)/zeolite composite was fabricated in this study. The composite was analyzed through field emission scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis, and weight loss test. FTIR and XRD results revealed a strong interaction among chitosan, PVA, and zeolite. Weight loss test results indicated that the composite was stable in acidic and basic media. Congo red was removed through flocculation, and the removal rate was 94% at an initial concentration of 100mg/L for a dose of 1g/L. The removal rate of methyl orange was controlled by adsorption at an initial concentration of less than 100mg/L. Flocculation occurred at high concentrations. The removal rate was also 94% at an initial concentration of 500mg/L for a dose of 5g/L. The adsorption behavior of the composite for the removal of methyl orange and Cr(VI) was described by using a pseudo-second-order kinetic model. The adsorption capacity of the composite for Cr(VI) was 450mg/g. Therefore, the synthesized composite exhibited versatility during the removal of dyes and heavy metals.

Ionic liquid entrapment by an electrospun polymer nanofiber matrix as a high conductivity polymer electrolyte

Through external doping, novel conductive polymer nanofibers were successfully fabricated using ionic liquids.

The extensor tendon splitting approach to the proximal interphalangeal joint: do we need to reinsert the central slip?

Current approaches to the proximal interphalangeal (PIP) joint have potential complications and limitations. We present a dorsal approach that involves splitting the extensor tendon in the midline, detaching the insertion of the central slip and repairing the extensor tendon without reinserting the tendon into the base of the middle phalanx. A retrospective review of 16 digits that had the approach for a PIP joint arthroplasty with a mean follow up of 23 months found a postoperative PIP active ROM of 61 degrees (range 25-90 degrees). Fourteen digits had no extensor lag, while two digits had an extensor lag of 20 degrees and 25 degrees. This modified approach is fast and simple and does not cause an extensor lag.

Hydrops fetalis associated with congenital myotonic dystrophy

We report a case of congenital myotonic dystrophy in a newborn infant who presented with hydrops fatalis. Clinical features were hypotonia, generalized edema, pleural effusion, respiratory distress, scalp hematomas, and tented mouth facies. Review of literature shows that congenital myotonic dystrophy is not a rare cause of nonimmune hydrops fetalis as previously thought.

Mechanism of lithium action on the adrenergic function

The intravenous injection of Lithium chloride (LiCl) in two dose levels (25 & 50 mg/kg) has led to a significant potentiation of the pressor response of rabbits to the i.v administration of both epinephrine and norepinephrine. The i.v injection of LiCl (50 mg/kg) resulted in a marked depression of the carotid occlusion reflex in rabbits. In vitro experiments revealed that LiCl (1.6 mcg/ml) and guanethidine (0.8 mcg/ml) exert the same action on the rabbit mesenteric nerve-intestine preparation and abolish the intestinal relaxation induced by electrical stimulation of the mesenteric nerve. Results confirm the assumption that Li might display a pre-synaptic, guanethidine-like, adrenergic neuronal blocking activity.

Childhood idiopathic thrombocytopenic purpura in Egypt and the neighboring Arab countries: a regional form with three different patterns of clinical expression

Childhood idiopathic thrombocytopenic purpura in the western world is essentially an acute self-limited disorder. In contrast, the clinical expression of the disease in Arab countries, as revealed by a study of 160 patients from Egypt, Saudi Arabia, Oatar and North Sudan, is heterogenous forming a spectrum that includes three distinct clinical forms: (a) the acute self-limited form, (b) the intermediate form, and (c) the chronic adulthood-like form. The relative proportions of these forms were 40. 15 and 45%, respectively. The chronic form shows limited response to steroids, and runs a platelet count less than 100,000 microliters for more than 1 year, with a tendency for later spontaneous elevation in platelet counts during the first few years of a long follow-up. The intermediate form shows a transient steroid-induced complete remission giving place to widely fluctuating platelet counts above and below 100,000 microliters once the steroid dosage is reduced to maintenance levels. Platelet counts in excess of 100,000 microliters were achieved in this group by extending steroid maintenance therapy fo 6--9 months. In spite of a tendency to chronicity and partial resistance to steroids i the intermediate and chronic forms, the overall response to steroids was enough both to reduce the number of cases requiring splenectomy to 15%, and to prevent the development of major complications in all the children included in the study.

Xanthinol nicotinate in the management of leg ulcers associated with haemoglobinopathies

The therapeutic role of xanthinol nicotinate, with its potent action on the peripheral circulation, in promoting healing of leg ulcers when added to conservative measures of ulcer treatment in adult beta-thalassaemia major and sickle cell thalassaemia, was evaluated in a double-blind crossover trial in 16 patients suffering from multiple leg ulcers. Conservative measures of ulcer treatment were leg raising in horizontal position for 14 hours, bed-rest, local antiseptic dressings and antibiotics. Xanthinol nicotinate or placebo was administered in a daily dose of 8 tablets (2400 mg) for 10 weeks. Comparison of the treatment results of conservative measures plus xanthinol nicotinate and those of conservative measures plus placebo revealed a statistically significant higher rate of complete ulcer healing during xanthinol nicotinate therapy (p less than 0.01). Apart from a low incidence of generalized itching and flushing at the start of the trial, xanthinol nicotinate was well tolerated in the prescribed dose.

Plexafer-F in the management of latent iron deficiency in pregnancy

The failure to prescribe in antenatal clinics a well tolerated form of supplementary oral iron that provides an adequate iron supply for the successful maintainance of active erythropoiesis in pregnant women largely accounts for the frequent development of latent iron deficiency in the child-bearing age.

The potential value of Plexafer-F*, a slow release ferrous sulphate preparation supplemented with folic acid, in reducing the high incidence of latent iron deficiency in pregnancy was assessed by conducting a randomized clinical trial of Plexafer-F and ordinary ferrous sulphate B.P. with folic acid in eighty women presenting early in pregnancy with latent iron deficiency. At the end of the trial, which was started at the sixteenth week of pregnancy and which lasted for twenty weeks, normal haematological values were obtained in thirty-eight out of forty patients (95%) taking Plexafer-F, but only in twenty-four out of forty patients (60%) taking ferrous sulphate. A simple screening test run on stool specimens provided during antenatal visits to check regular ingestion of the iron preparations prescribed, revealed regular drug intake and no intolerance in all the patients receiving Plexafer-F, against an intolerance leading to failure of regular drug intake in 37.5% of patients receiving ordinary ferrous sulphate.

Amoxycillin in treatment of typhoid fever in patients with haematological contraindications to chloramphenicol

Thirty adults with proved typhoid fever were treated with amoxycillin 1 g six-hourly by mouth for an average of 14 days because of haematological contraindications to chloramphenicol. Eighteen patients were Egyptian men with the Mediterranean variety of glucose-6-phosphate dehydrogenase deficiency and an enzyme activity in the red cells fanging from 0 to 3%, and 12 patients had a history of severe but reversible myelosuppression after eight to 12 days' treatment with chloramphenicol 1-5-2 g daily. The clinical and bacteriological responses in this group of patients were compared with those of 30 haematologically normal patients of comparable age and sex treated with chloramphenicol. The results showed that amoxycillin is an effective alternative to chloramphenicol for treating typhoid fever in patients with haematological contraindications to chloramphenicol.

Potentiation by lithium and protection by rubidium of digitalis intoxication

Investigating the effects of Li and Rb on the toxicity of digoxin and ouabain revealed Li to be a potentiator while Rb to be a protector. The effects of Rb in this respect are, more or less, qualitatively comparable to those of K; the intensity of Rb effects is more than that of K. In case of digoxin the effect produced from the combined use of both Rb and K is more than each individual effect. With ouabain, however, whereas Rb offered protection K failed to do so. Electrolyte changes in cardiac tissue showed that Li increased the tissue content of Ca while Rb produced the opposite effect. In comparing Rb with K, both increased the K level in the cardiac muscle. However, in the case of ouabain the infusion of K failed to decrease the Ca level and this might explain its failure to protect against ouabain toxicity. This points to the importance of Ca, rather than K, in controlling the excitability of the cardiac muscle and in effecting the toxicity of cardiac glycosides. Evidences presented indicate the superiority of Rb over K and propose its trial in clinical practice.

Immunoblastic lymphosarcoma, a cytological and clinical entity?

We have studied 20 cases of haematosarcomas belonging to lymphosarcomas (T or B-cell markers, absence of the reticulosarcoma characters in sections, on smears, with conventional and scanning electron microscopy). Their cells which appear as large pyroninophilic cells on sections, as large very basophilic cells with blastic nuclei and often cytoplasmic vacuoles on smears, as having many polyribosomes and usually no ergastoplasm with conventional electron microscopy, and as large cells of the lymphocytic series with scanning electron microscopy resemble the cells which we described in adenitis in 1955 (9) and in the graft-versus-host-reaction in 1961 (6), which Gowans (15) showed resulted from lymphocyte transformation, and which Dameshek (10) called immunoblasts. Many of these cases of immunoblastic lymphosarcoma (ILS) identified on their cytohistological characteristics [also recognized by Lukes et al. (24, 25) and Lennert et al. (21, 22)], present aetiological, clinical and pronostic characters which let us suppose that it may be not only a cytological entity but also a cytoclinical entity : a) it affects males in 85% or the subjects; eight patients came from mediterranean countries outside France; two patients had a history of chronic rheumatoid manifestations; b) the disease was at stage IV at the first presentation in 10 patients out of 20; it was revealed by profound (mediastinal or abdominal) localizations in 60% of cases (12 out of 20); it presented a hypoglobulinaemia in eight out of 13 patients; in six out of the 15 patients treated before leukaemic conversion, the chemotherapy usually efficient in lymphosarcoma (LS) failed to induce remission. This type of LS has a poorer prognosis than other types of LS (median for all stages : eight months). It led to the death either after its conversion to leukaemia (nine out of 20 cases), or by vital organ (as brain or kidney) infiltrations.

High dose ascorbic acid in the management of thalassaemia leg ulcers--a pilot study

Eight patients with beta thalassaemia major suffering from leg ulcers, were treated over an 8-week period with 3 g ascorbic acid daily in a controlled double-blind crossover study. The ulcers of all the patients showed a high rate of either complete or partial healing.

Myeloma cells in the cerebrospinal fluid in plasma cell neoplasia

Myeloma cells were detected in the cerebrospinal fluid of two patients with plasma cell neoplasia during the myelographic studies of 38 patients whose myeloma was associated with extensive neurological complications. The myeloma cells were looked for in Wright stained centrifuged deposit of 2-5 ml samples of the cerebrospinal fluid obtained during myelography. The possibility that occult traumatic lumbar puncture had allowed entry of circulating myeloma cells from the peripheral blood into the subarachnoid space was excluded by the absence of myeloma cells in smears of peripheral blood and its buffy coat. Up to the end stages of the disease the meningeal myeloma lesions remained microscopical and no signs of raised intracranial tension were manifested by either patient.

Simple test for ingested iron in hospital and domiciliary practice

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