Carboxymethyl guar gum nanoparticles for drug delivery applications: Preparation and preliminary in-vitro investigations.

Carboxymethyl guar gum (CMGG) synthesized from commercially available polysaccharide was formulated into nanoparticles via ionic gelation using trisodium trimetaphosphate (STMP) as cross-linking agent. Characterisation using a range of analytical techniques (FTIR, NMR, GPC, TGA and DLS) confirmed the CMGG structure and revealed the effect of the CMGG and STMP concentration on the main characteristics of the obtained nanoformulations. The average nanoparticle diameter was found to be around 208 nm, as determined by dynamic light scattering (DLS) and confirmed by scanning electron microscopy (SEM) and nanoparticle tracking analysis (NTA). Experiments using simulated gastric and intestinal fluids evidenced significant pH-dependent drug release behaviour of the nanoformulations loaded with Rhodamine B (RhB) as a model drug (loading capacity in excess of 83%), as monitored by UV-Vis. While dose-dependent cytotoxicity was observed, the nanoformulations appeared completely non-toxic at concentrations below 0.3 mg/mL. Results obtained so far suggest that carboxymethylated guar gum nanoparticles formulated with STMP warrant further investigations as polysaccharide based biocompatible drug nanocarriers.

Flaxseed lignan wound healing formulation: characterization and in vivo therapeutic evaluation.

Flaxseed lignans are a natural source of useful biologically active components that show a diverse spectrum of health-promoting properties. The valuable effects of the phenolic molecules are mainly due to their antioxidant activity by preventing oxidative stress and stimulate collagen synthesis, therefore, providing benefits to the skin. The present work highlights the development of flaxseed extract formulation as novel wound healing agent. The recognition of key structural features within flaxseed extract was crucial for the design and development of the therapeutic cream. Chromatographic analyses were employed for bioactive compounds identification and quantification. Folin-Ciocalteu method determined the total phenolic content and the antioxidant properties were evaluated by DPPH assay. The storage and loss modulus and tan δ were calculated for cream rheological properties evaluation. In vitro diffusion capacity and in vivo wound healing activity of phenolic cream were evaluated on Wistar rats. The collective properties and healing effect of the flaxseed suggested wound healing capacity.

Antibacterial quaternized gellan gum based particles for controlled release of ciprofloxacin with potential dermal applications.

This paper presents the synthesis and characterization of gellan gum derivatives containing quaternary ammonium groups, with the purpose of obtaining particulate controlled release systems for ciprofloxacin. Quaternized gellan derivatives were synthesized by grafting N-(3-chloro-2-hydroxypropyl)-trimethyl ammonium chloride onto gellan primary hydroxyl groups by nucleophilic substitution, in the presence of alkali, under specific reaction conditions using various gellan/N-(3-chloro-2-hydroxypropyl)-trimethyl ammonium chloride molar ratios. Degree of quaternization was determined by (1)H NMR spectroscopy and AgNO3 conductometric titration. Thermal behavior was investigated for all materials by thermogravimetric analysis. A study of the degree of quaternization and effect of the reaction conditions upon activation energy of quaternized gellan derivatives for the main degradation step by applying the Kissinger method at four heating rates is also reported. The novelty that this work brings refers to obtaining quaternized gellan and chitosan based particles with retention of quaternary ammonium moieties' antibacterial activity. In vitro transdermal release tests of ciprofloxacin from loaded particles were carried out on rat skin in isotonic phosphate buffer solution (pH=7.43). Ciprofloxacin was released up to 24 h, confirming quaternized gellan-chitosan particles' potential as controlled release systems for topical dermal applications.

Synthesis and characterization of N-(2-aminoethyl)-2-acetamidyl gellan gum with potential biomedical applications.

N-(2-aminoethyl)-2-acetamidyl gellan gum (GCM-EDA) was prepared by carboxymethylation (via nucleophilic substitution of primary hydroxyl groups of the ß-D-glucose unit of gellan gum, in the presence of alkali and chloroacetic acid) and reaction with tert-butyl N-(2-aminoethyl) carbamate (N-Boc-EDA) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as an activator, followed by deprotection with trifluoroacetic acid. The structural confirmation and characterization of N-(2-aminoethyl)-2-acetamidyl gellan gum was performed by spectroscopic, rheological and thermogravimetric analysis, and in vitro tests showed a lack of cytotoxicity which is indicative of the potential of this material to be used in biomedical applications.

In vitro evaluation of biomimetic chitosan-calcium phosphate scaffolds with potential application in bone tissue engineering.

This work reports on the physicochemical properties and in vitro cytotoxicity assessment of chitosan-calcium phosphate (Cs-CP) scaffolds for bone tissue engineering, which were synthesized by a novel biomimetic co-precipitation method. X-ray diffraction (XRD) along with scanning electron microscopy (SEM) analysis confirmed the porous morphology of the scaffolds and the amorphous nature of the inorganic phase with different crystallite sizes and the formation of various forms of calcium phosphate. Compressive mechanical testing revealed that the Young's modulus of the biomaterials is in the range of human trabecular bone. In vitro tests were performed on the biomaterials for up to 14 days to study the behavior of the osteoblast-like human cell line (MG63), primary human osteoblasts (HOS) and human dermal microvascular endothelial cells (HDMEC). The cytotoxicity was evaluated by the MTS assay for cell metabolism and the detection of membrane integrity (lactate dehydrogenase-LDH release). An expression of the vascular endothelial growth factor (VEGF) in the cell supernatants was quantified by ELISA. Cell viability gave values close to untreated controls for MG63 and HOS, while in the case of HDMEC the viability after 2 weeks in the cell culture was between 80-90%. The cytotoxicity induced by the Cs-CP scaffolds on MG63, HOS and HDMEC in vitro was evaluated by the amount of LDH released, which is a sensitive and accurate marker for cellular toxicity. The increased levels of VEGF obtained in the osteoblast culture highlights its important role in the regulation of vascularization and bone remodeling. The biological responses of the Cs-CP scaffolds demonstrate a similar proliferation and differentiation characteristics of the cells comparable to the controls. These results reveal that biomimetic Cs-CP composite scaffolds are promising biomaterials for bone tissue engineering; their in vivo response remains to be tested.

Nanostructured chitosan-surfactant matrices as polyphenols nanocapsules template with zero order release kinetics.

Nanostructured membranes and films of cationic surfactant-chitosan with tannic acid as polyphenol model were obtained by phase inversion method. The membranes were investigated by Attenuated Total Reflectance Fourier Transform InfraRred, X-Ray Diffraction, Scanning Electron Microscopy and Thermogravimetry, and the films topography was analysed by Atomic Force Microscopy. The analysis reveals that the interactions at the molecular level between cationic CTAB surfactant and cationic chitosan polymer strive to weaken membrane stability, whereas, the tannic acid is favoured to cluster with CTAB and diminish the membrane thermodynamic instability. The nanocapsules formed, with dimensions in the range of 16.35-27.68 nm, are congregating in clusters having dimensions in the domain of 50-300 nm. The layers resulted from these nanostructures arrangement constitute a surfactant-chitosan matrix with tannic acid suitable for drug controlled release with zero order kinetics.

Aspergillus fumigatus meningitis in immunosuppressed patients; diagnosis, management, prevention and control.

Aspergillosis is a fungal disease that may be expressed by a diversity of clinical syndromes being produced by several of more than 170 Aspergillus species. The "Matei Bals" National Institute for Infectious Diseases has a long experience in diagnostic procedures and treatment of the immunosuppressed patients. Irrespective of the place of their residence, most patients with HIV infection and AIDS were investigated in the Institute in the last two decades. The first case of double central nervous infection (Mycobacterium tuberculosis and Aspergillus fumigatus) in a HIV positive patient is discussed.

Molecular analysis of the first avian influenza H5N1 isolates from fowl in Romania.

Since the events of avian influenza (AI) caused by H5N1 subtype from Hong Kong (1997), the people worldwide have been confronted with new waves of epizootic influenza. In 2005 in Romania an unprecedent H5N1 epizootic occurred in domestic and wild birds. Therefore an immediate investigation by molecular approach of this highly pathogenic H5N1 strain was necessary. The virus isolation and the RNA extraction were performed in the Institute of Diagnosis and Animal Health while PCR and sequencing were carried out in Cantacuzino Institute. Herein we report the first evidence of H5N1 presence in Romanian fowls. The phylogenetic analysis of haemagglutinin and neuraminidase gene indicated a close relationship of Romanian strains to those from Siberia and China. The virological and molecular analysis of the first strains of avian virus from Romania confirmed the presence of H5N1 subtype, belonging to the genetic line Z. These results indicate that the avian virus from this genetic line is directly derived from the highly pathogenic viruses isolated in China and Russia in 2005.

Immunity status against coxsackie viruses B in 25 patients with acute myocarditis.

Viruses are an important cause of myocarditis, particularly the enterovirus group B coxsackievirus. Viral infection may be suspected on the basis of history and presentation and can be proved by direct or serological identification of virus. Twenty-five patients were diagnosed with acute myocarditis and were investigated with a serologic test battery covering Coxsackie viruses group B types 1 to 5 at the National Reference Center for Enteroviruses in Cantacuzino Institute Bucharest, Romania. A possible Coxsakie B virus etiology could be documented in 11 from 25 cases with acute myocarditis and high titers against Coxsackie virus B type 2 (1 patient), type 3 (5 patients) and type 5 (in 4 patients) were detected. In one HIV positive patient (17 years old), a concomitant infection with Coxsackie virus B types 2 and 4 was detected. The earlier detection of enterovirus myocarditis could be followed by antiviral therapies with a potential therapeutic role.

Establishing of a minimal set of tests (minimal standards) to identify species included in the genus Mycobacterium.

Mycobacterium genus includes over 100 species and subspecies; new species are discovered every year. Minimal standard criteria are represented by the resistance to acid-alcohol (e.g. in the Ziehl - Neelsen staining), the presence of some mycolic acids containing 60-90 carbon atoms that can be cleaved by pyrolysis in fatty acids with 22 - 26 carbon atoms and a guanine + cytosine content of the DNA of 61 to 71 mol %. The species with the highest rate of involvement are those from Mycobacterium tuberculosis complex, and tuberculosis is still one of the most widespread world diseases. The most important for a laboratory is to be able to identify the species from M. tuberculosis complex. We have done a series of experiments, their goal being to evaluate and establish a minimal set of useful tests for identification of mycobacterial species. We used strains from "Cantacuzino" Institute collection and applied a series of classical and modern methods. We appreciate that the minimal set of tests could be represented by the microscopic examination for acid-fast bacilli (AFB), the examination for the preferred growth temperature, the growth rate, the colonies morphology, pigmentation and photo reactivity, the niacin accumulation test, the test of nitrate reduction, the catalase test (in both variants), plus the susceptibility to Para-Amino Salicylic Acid, Para-Nitro-Benzoic Acid andto Tiophene-2-Carboxylic Acid Hydrazide.

Rapid immunochromatographic serum assay of nontuberculous mycobacterial infections.

A rapid immunochromatographic serologic assay (Dot assay) is proposed to be applied on patients infected with nontuberculous mycobacteria (NTM). This assay could evidentiate the infecting species and allow the beginning of the treatment. The test is based on the principle of immunoblotting chromatography, a rapid membrane-based assay, capable of diagnosing NTM infections in serum, in less than 1 hour, with no need of special equipment or skilled staff. The secreted extracellular antigens have been isolated from the unheated culture filtrates of the clinically significant NTM (M. avium, MAI, M. kansasii, M. xenopi, M. chelonaei, M. scrofulaceum, M. marinum, M. fortuitum, M. abscesus, M. szulgai). The patients have been tested against these antigens, as well as from M. tuberculosis H37Rv, due to the possibility of co-infection with tuberculous bacilli. A number of 385 tests on patient sera have been performed (10, with NTM suspected infection, with or without M. tuberculosis co-infection, 5 with confirmed diagnosis of NTM infection, 10 with TB, 10 with other respiratory diseases). The preliminary results presented in this paper support the fact that the rapid immunochromatographic serum assay, combined with clinical and radiographic evidence, could evidentiate the infecting NTM species and allow the start of an earlier treatment, but must be confirmed on a higher number of patients.

Case-control study to evaluate the link between immunosuppression and Candida spp. infection.

Candidiasis is one of the fungal infections with the highest incidence in the immunosuppressed host. The evolution of infection and the increase of antifungal medical drugs resistance could both contribute to the mortality attributable to Candida infection in the immunosuppressed host. Even though the data from international studies are well known, few studies have been published in Romania on this subject. In the case-control study we demonstrated the link between the immunosuppression and the presence of Candida infection. Further studies are to be carried out in order to identify more accurately this link and to extend the study to other fungi. There is a need to increase the microbiological diagnosis use at least at the hospital laboratory level in order to better identify the real situation of fungal infections and the link between them and the concrete status of different hosts. Continued surveillance for infections caused by C. albicans and other species of Candida among hospitalized patients is recommended. Control of antimicrobial resistance among nosocomial infections caused by C. albicans and other species of Candida requires rational policies for use of both antifungal and antibacterial agents and appropriate surveillance for the emergence of resistant strains and species.

Recommendations for fungal opportunistic infections prevention in persons infected with human immunodeficiency virus.

Fungal infections have become important causes of morbidity and mortality in immunocompromised hosts, including those with the acquired immune deficiency syndrome (AIDS). Although significant therapeutic advances are being made in the field of antiretroviral therapy, parallel advances must be attained in the management of secondary infections, including those due to fungi. As increasing numbers of people with HIV infection come in to medical attention, the problem of fungal infections will also increase, requiring innovative approaches toward understanding the pathogenesis of these infections and developing new diagnostic and therapeutic modalities. A better understanding is required for the immunopathogenesis of fungal infections. Improved understanding of new and established antifungal agents in conjunction with ART agents as well as immune modulators, should yield important advances in prevention, control and treatment of fungal infections of HIV infected people.

Malaria in the whole world and in Romania.

Malaria is the world's most important tropical parasitic disease. Malaria is a public health problem today in more than 90 countries. Worldwide prevalence of the disease is estimated to be in the order of 300-500 million clinical cases each year. Malaria is endemic in a total of 101 countries and territories. In Romania, malaria does not represent an important public health problem. In 1999, there were reported a total number of 32 malaria cases in Romanian people. 78% from these recognized as etiological agent Pl. falciparum. The malaria cases imported from Turkey (5) have had as etiological agent Pl. vivax. The most affected age group is between 21-50 years and a distribution by profession shows that sailor personnel accounts for 65.6% of all cases. Africa remains the most important endemic region from where the malaria cases in Romanian people are imported. An adequate chemoprophylaxis is not, yet, easy to obtain for Romanian people who are travelling abroad in endemic countries because of the lack of specific drugs (especially for resistant forms of Pl. falciparum). Even if the Romanian Ministry of Health had elaborated orders regarding malaria and Cloroquine is the usual drug administered, as chemoprophylaxis, to Romanian people who travel abroad, in each year in our country appears around 30-60 imported malaria cases. That is the cause why Romanian Ministry of Health wants to solve this problem which is the major cause of the malaria cases in Romanian people.

[Acute infectious diarrheal disease in Romania: 1993-1998]. / Boala diareica acuta infectioasa în Romania: 1993-1998.

The decrease of morbidity-mortality caused by gastroenteritis is in relation to the factors largely responsible for the fall in infant mortality and mortality from communicable diseases in developing countries. Nevertheless, diarrhea is still a considerable public health problem in these countries, especially among children under 5 years old. 98% of all deaths in children younger than 15 years are in the developing world. Five of the ten leading killers are communicable, perinatal, and nutritional disorders largely affecting children. The knowledge of the etiology and epidemiology of childhood diarrhea in a given area is needed to plan any measure designed to prevent or ameliorate diarrheal illness and to develop practical guidelines for the most appropriate examination procedures. In Romania, although the real data of morbidity by acute diarrhea are not known, the reports show a significant decrease in the past 10 years. In 1993, 420.2 cases at 100,000 inhabitants were reported, the most commonly affected being the children age 0-4 years. The incidence decreased to 338.5 cases at 100,000 inhabitants in 1997 (and a quite similar incidence for the first 11 month of 1998). Between 1993-1998, 527,977 cases were reported (58.1% in urban area), with a higher frequency in spring-autumn season. Antibiotics are not required in case of acute diarrhea with little or no fever. Antibiotics could be discussed for cholera-like diarrhea and are required in case of invasive bacterial diarrhea, shigellosis, cholera, and Clostridium difficile as well as diarrhea with fever and sanguinolent stools in infants or salmonella-induced diarrhea with signs of extradigestive complications. Importance of oral rehydration solution in the treatment of diarrhoeal diseases is well known. It can be applied to all types of diarrhoea, practically, without any side effects, complications, such aas hypernatraemia is avoidable. It has proved to be effective for dehydration caused by diarrhoea and for diarrhoea, too. There is a need for effective infection control policies, which include appropriate training of staff; simple surveillance systems and readily available expert advice to ensure that outbreaks are rapidly controlled. Approaches to prevention include education about risk factors, which often fails to lead to modification of risky behavior. Further regional epidemiological studies are necessary to develop more appropriate management guidelines.

[The epidemiological process of West Nile viral infection]. / Procesul epidemiologic al infectiei cu virusul West Nile.

An important number of arboviruses are known to produce clinical or subclinical infections in humans. Most of these viruses are maintained in zoonotic cycles and are transmitted by mosquitoes or ticks. Viruses believed to be associated with human disease are classified according to the type of vector, the main clinical sign and the geographic distribution. The arboviruses are classified in families and genera, of which Togaviridae, Flaviviridae and Bunyaviridae are the best known. West Nile virus is present in Egypt, Israel, India and is widespread in parts of Africa, the northern Mediterranean area and Western Asia. The first major West Nile fever epidemic in Europe occurred in Romania, in 1996, with a high rate of neurological infections. 393 patients with serologically confirmed or probable West Nile fever infection (352 had acute central-nervous-system infections) were identified. The number of mild cases could not be estimated. WN virus was recovered from Culex pipiens mosquitoes. The virus is not transmitted through direct human contact, probably the infected mosquitoes transmit the virus throughout their life. Viremia is essential for vector infection and occurs during early clinical illness in humans. Susceptibility appears to be general, in both males and females, throughout life. Inapparent infections and mild disease are common.