Recent advances and perspectives on coated alginate microspheres for modified drug delivery

BACKGROUND: Alginate microspheres represent a useful tool for modified drug delivery. Their preparation is quite easy and is usually based on the gelling properties of the polysaccharide in the presence of divalent ions; nevertheless, microparticles prepared only with calcium alginate show several problems, mainly related to the mechanical stability and to the release that, in most cases, is too fast. To overcome such inconveniences, polymer-coated alginate microspheres and/or appropriately interpenetrating polymer network (semi-IPNs and IPNs) structures formed with alginate and other macromolecules were developed. OBJECTIVE: This article reports a synthetic overview on the most recent searches carried out on coated alginate microspheres. METHODS: After a section focused on the microsphere preparation, this article is divided into several main topics related to the specific polymer that was used as a coating material to provide a rationale in reporting literature data. In the last section, the advantages and disadvantages of the various approaches are discussed and the authors' opinion on perspectives for further studies and novel applications of coated alginate microspheres are reported. CONCLUSION: Ca(2+)-alginate microparticles could experience a new era if scientists will increase their efforts in developing microparticles with smart properties.     

Disorders of sexual development and abnormal early development in domestic food-producing mammals: the role of chromosome abnormalities, environment and stress factors

The management of disorders of sexual development (DSD) in humans and domestic animals has been the subject of intense interest for decades. The association between abnormal chromosome constitutions and DSDs in domestic animals has been recorded since the beginnings of conventional cytogenetic analysis. Deviated karyotypes consisting of abnormal sex chromosome sets and/or the coexistence of cells with different sex chromosome constitutions in an individual seem to be the main causes of anomalies of sex determination and sex differentiation. In recent years, a growing interest has developed around the environmental insults, such as endocrine-disrupting compounds (EDC) and heat stressors, which affect fertility, early embryonic development and, in some instances, directly the sex ratio and/or the development of 1 specific sex versus the other. A variety of chemical compounds present in the environment at low doses has been shown to have major effects on the reproductive functions in human and domestic animals following prolonged exposure. In this review, we present an overview of congenital/chromosomal factors that are responsible for the DSDs and link them and the lack of proper embryonic development to environmental factors that are becoming a major global concern.     

Assignment of genes for immunoglobulin kappa and heavy chains to chromosomes 6 and 12 in mouse.

Using somatic cell hybrids from fusions of lymphocytes of two different mouse stocks with the myeloma cell line X63-Ag8, we have assigned genes for the immunoglobulin heavy and kappa-type light chains to chromosomes 12 and 6, respectively. The two mouse stocks exhibit karyotypes consisting of nine pairs of metacentric chromosomes as a result of centric fusions of acrocentric chromosomes in different combinations. In the hybrid cells these metacentric chromosomes can be distinguished from the acrocentric chromosomes of myeloma origin, permitting correlation of Ig chain expression with mitotic loss of individual metacentric chromosomes.     

Prenatal sonographic imaging of an immature intracranial teratoma.

This article describes the prenatal sonographic diagnosis of a rare case of intracranial immature teratoma in a fetus at the 35th week of gestation which looked normal at previous examinations. At sonography a markedly enlarged fetal head containing a complex irregular mass and hydrocephalus was detected. Color Doppler examination of the mass showed intense vascularization with low resistance flows.     

Nickel-induced allergy and contact dermatitis: does it induce autoimmunity and cutaneous sclerosis? An experimental study in Brown Norway rats

Nickel sensitization is a growing problem and the most common cause of allergic contact dermatitis. The aim of this study was to investigate whether nickel chloride can induce autoimmunity and cutaneous sclerosis in immunosensitive rats. Nickel chloride, in a dose of 4.5 mg in 0.2 ml NS, was administered by the oral and subcutaneous routes to 20 Brown Norway rats. Autoantibodies (ANA, anti-RNP, anti-SCL70 and anti-centromere) were measured and compared in pre- and post-challenge serum samples. Histological studies were also performed in skin biopsies obtained from six positively responding rats and compared with an equal number of control rats at the 14th week post-challenge. Serum ANA was high in a significant number of rats in both the oral (P < 0.005) and subcutaneously nickel-treated groups (P = 0.02), while the anti-SCL70 was high in a significant number of rats in only the orally nickel-treated group (P = 0.04). Histologically, subcutaneous and oral nickel-treated groups showed sclerodermic features of the skin (P = 0.22, P = 0.5), respectively. It may be concluded that nickel chloride can induce scleroderma-related autoantibodies and cutaneous sclerosis. More prolonged duration of exposure is probably associated with greater risk. This is the first study showing the potential risk of nickel in triggering the development of cutaneous sclerosis in susceptible hosts.     

Effect of vitamin E administration on response to ischaemia-reperfusion of hearts from cold-exposed rats

In both 3,5,3-triiodothyronine (T(3))-induced hyperthyroidism and cold-induced functional hyperthyroidism, the heart displays an increased susceptibility to oxidative challenge in vitro. Hearts from T(3)-treated rats also exhibit an increased susceptibility to ischaemia-reperfusion, a condition that raises free radical production. The present study was designed to establish whether cold-exposed rats exhibit an increased cardiac susceptibility to ischaemia-reperfusion which can be attenuated by vitamin E. The following four groups of animals were used: C, control rats (n = 8, temperature 24°C); C+VE, vitamin E-treated rats (n = 8, temperature 24°C); CE, cold-exposed rats (n = 8, temperature 4°C); and CE+VE, cold-exposed vitamin E-treated rats (n = 8, temperature 4°C). Langendorff preparations from these animals were submitted to 20 min ischaemia followed by 25 min reperfusion. At the end of the ischaemia-reperfusion protocol, homogenates and mitochondria were prepared and used for analytical procedures. With respect to control hearts, cold hearts showed a lower inotropic recovery and a higher oxidative stress, as inferred by higher levels of oxidized proteins and lipids and lower reduced glutathione levels. These changes were prevented when cold rats were treated with vitamin E. Evidence was also obtained that mitochondria are involved in the tissue derangement of cold hearts. Indeed, they display a faster production of reactive oxygen species, which causes mitochondrial oxidative damage and functional decline that parallel the tissue dysfunction. Moreover, vitamin E-linked improvement of tissue function was associated with a lower oxidative damage and a restored function of mitochondria. Finally, the mitochondrial population composition and Ca(2+)-induced swelling data indicate that the decline in mitochondrial function is in part due to a decrease in the amount of the highly functional heavy mitochondria linked to their higher susceptibility to oxidative damage and swelling. In conclusion, our work shows that vitamin E treatment attenuates harmful side-effects of the cardiac response to cold, such as oxidative damage and susceptibility to oxidants, thus preserving mitochondrial function and tissue recovery from ischaemia-reperfusion.