Association of ionophores, yeast, and bacterial probiotics alters the abundance of ruminal microbial species of pasture intensively finished beef cattle

The effect of the association of non-protein nitrogen, yeast, and bacterial probiotics on the ruminal microbiome of beef cattle intensively finished on pasture was evaluated. The experiment was carried out in a completely randomized design with five treatments and four replications. The treatments consisted of a group of animals kept on pasture that received low consumption supplementation (LS) and four groups that received for 98 days, 17.5 g concentrate kg^-1 body weight. The supplements were composed of the association of additives: urea (U), slow-release non-protein nitrogen (U+SRN), yeast (Saccharomyces cerevisiae; U+SRN+Y), and bacterial probiotics (live strains of bacteria; U+SRN+Y+BP). All supplements also contained salinomycin and virginiamycin. After slaughtering the animals, samples of ruminal content were collected to quantify groups of fibrolytic bacteria (Ruminococcus albus and Fibrobacter succinogenes), non-fibrolytic (Prevotella ruminicola, Selenomonas ruminantium, and Streptococcus bovis), Archaea, and ciliate protozoa, using the qPCR technique. The abundance of F. succinogenes was the same for the LS animals and those that received the supplement U+SRN+Y (1.42×10⁸ copies mL^-1) but higher than the other treatments. Supplementation reduced by 90% the abundance of S. bovis compared to the LS. The inclusion of yeast increased the abundance of fibrolytic bacteria by 2.2-fold. For animals that received the supplement U+SRN+Y+BP and the LS, there was no difference for non-fibrolytic bacteria (3.07×10⁹ copies mL^-1). The use of yeasts and sources of non-protein nitrogen in high-concentrate diets for beef cattle stimulates the growth of fibrolytic bacteria, which can contribute to the reduction of digestive disorders and metabolic diseases in animals that receive diets with high concentrate in pasture intensive termination systems.

Species diversity of Marmosa subgenus Micoureus (Didelphimorphia, Didelphidae) and taxonomic evaluation of the white-bellied woolly mouse opossum, Marmosa constantiae

Marmosa subgenus Micoureus contains six currently recognized species, distributed from southern Belize to northern Argentina. Although recent studies have demonstrated the monophyly of the subgenus, the species have not been recently revised. Except for M. phaea, we evaluated the species diversity in this subgenus of mouse opossums using integrated morphological, morphometric and molecular data, with emphasis on M. constantiae. We used a total of 700 specimens for morphological and morphometric analyses. For phylogenetic, species delimitation, molecular variance and population structuring analyses (the latter two only for M. constantiae), we used the mitochondrial cytochrome b gene. Morphometric variation patterns were evaluated through Principal Component Analysis and Discriminant Function Analysis. Our results indicate that there are seven species in our samples. Among the species analysed morphologically, some can be discriminated by craniodental measurements and all can be discriminated through morphology. Marmosa constantiae is polyphyletic, composed of two lineages, one of which is correctly named M. budini. Marmosa constantiae (s.s.) has a well-known genetic structure, with no clear geographic structure and no consistent morphological patterns. Several records of M. demerarae in the literature correspond to M. constantiae. Marmosa demerarae may thus represent a complex formed of at least two species.

Estudo dos cromossomos de uma espécie do gênero Ancistrus (Siluriformes: Loricariidae) proveniente do córrego Tamanduá, bacia do Rio Paraguai, Mato Grosso

O gênero Ancistrus é um dos mais diversificados da tribo Ancistrini, possuindo atualmente 64 espécies nominais. O grupo é diferenciado dos demais loricariideos pela ausência de placas e odontódeos na margem anterior do focinho, onde existem apenas pequenos tentáculos carnudos e odontódeos interoperculares bem desenvolvidos. Diversas espécies do gênero Ancistrus já foram descritas na região das bacias dos rios Amazonas e Paraguai. Estes peixes têm a taxonomia bastante duvidosa, não existindo ainda uma chave precisa de identificação para estas espécies. Ferramentas citogenéticas como análise de número diploide, detecção de AgNORs, bandamento C e análises de citogenética molecular funcionam como importantes marcadores, utilizados para a diferenciação de população e de espécies de Ancistrus. Dessa forma, o presente trabalho teve como objetivo caracterizar os cromossomos de uma espécie de Ancistrus proveniente do córrego Tamanduá (Bacia do Rio Paraguai) utilizando técnicas de coloração convencional e FISH (18S), e comparar as características de seu cariótipo com o de outras espécies provenientes das demais localidades desta mesma bacia. A espécie estudada apresenta um número diploide de 2n=44 cromossomos, com fórmula cariotípica igual a: 9 pares m, 8 pares sm, 3 pares st e 2 pares a, o bandamento C evidenciou poucas marcações, estas sempre nas regiões cetroméricas, e duas grandes bandas coincidentes com a NOR. A técnica de FISH usando como sonda o rDNA 18S detectou duas marcações nas regiões intersticiais dos braços longos de dois cromossomos submetacêntricos, sendo que estas marcações coincidem com as regiões AgNOR positivas Algumas características do cariótipo desta espécie se assemelham com a de outras espécies encontradas nas demais localidades da bacia do Rio Paraguai, como por exemplo o número diploide de 2n=44 com NOR em regiões intersticiais encontrados em Ancistrus cf. dubius e Ancistrus sp. 12 (Córrego Santa Cruz Cuiabá). Contudo outras características do cariótipo da espécie estudada são divergentes, como a presença de cromossomos acrocêntricos e a marcação do rDNA18S localizada no braço longo de cromossomos submetacêntricos. Tais características confirmam as evidências sobre a grande diversidade cariotípica encontrada no gênero, mesmo entre espécies com mesmo número de cromossomos, e também mostram como determinados caracteres dos diferentes cariótipos podem ser uteis na separação das espécies desta região.Apoio Financeiro: FAPESP (2013/17826-9)

Karyotype Diversity in Doradidae (Siluriformes, Doradoidea) and Presence of the Heteromorphic ZZ/ZW Sex Chromosome System in the Family

Karyotypes and other chromosomal markers as revealed by conventional and molecular cytogenetic protocols in four species of the catfish family Doradidae from the Araguaia-Tocantins river basin, namely Hassar wilderi, Leptodoras cataniae, Tenellus leporhinus and Tenellus trimaculatus were examined. All species had diploid chromosome number 2n = 58 and karyotypes dominated by biarmed chromosomes, simple NOR phenotype, that is, one chromosome pair bearing this site in terminal position, but some differences in karyotypes and distribution of constitutive heterochromatin, position of rDNA sites. Such characteristics appeared species-specific. A ZZ/ZW sex chromosome system was found in Tenellus trimaculatus, resulting likely from the amplification of the heterochromatin, followed by a paracentric inversion. Our results confirmed low karyotype differentiation observed until now among representatives of this endemic catfish family.

Cytogenetic and Molecular Data Support the Occurrence of Three Gymnotus Species (Gymnotiformes: Gymnotidae) Used as Live Bait in Corumbá, Brazil: Implications for Conservation and Management of Professional Fishing

In the Pantanal of Mato Grosso do Sul, electric fish (Gymnotus spp.) are the primary source of live bait, accounting for more than three-quarters of total sales. Based on chromosomal and molecular markers, the present study attempted to identify the Gymnotus species used as bait in the region of Corumbá, Mato Grosso do Sul, Brazil. Three species were detected, based on their distinct karyotypes: G. paraguensis (2n = 54), G. sylvius (2n = 40), and G. pantanal (2n = 39-40, X₁X₂Y/X₁X₁X₂X₂), with no evidence being found of interspecific hybrids. All three species presented a single nucleolar organizer regions (NOR) (heterochromatin CMA₃⁺/DAPI^-) and pericentromeric heterochromatin in almost all chromosomes, with a few distal and/or interstitial blocks. G. sylvius and G. pantanal had one and two pairs of chromosomes with 5S rDNA sites, respectively, while G. paraguensis had 17 chromosome pairs with these markers. The three species formed well-defined clusters in the DNA barcoding analysis. The integrated analysis of the cytogenetic and DNA barcoding data confirmed that the diversity of Gymnotus species exploited as live bait in the study region has been underestimated. These findings indicate that the markers analyzed represent valuable tools for the conservation and fishery management of the Gymnotus stocks exploited.

Subgingival bacterial community profiles in HIV-infected Brazilian adults with chronic periodontitis

BACKGROUND AND OBJECTIVE

To compare the subgingival microbial diversity between non-HIV-infected and HIV-infected individuals with chronic periodontitis using denaturing gradient gel electrophoresis (DGGE).

MATERIAL AND METHODS

Thirty-two patients were selected: 11 were HIV-infected and 21 were non-HIV-infected, and all had chronic periodontitis. Periodontal measurements included probing depth, clinical attachment level, visible supragingival biofilm and bleeding on probing. Subgingival biofilm samples were collected from periodontal sites (50% with probing depth ≤ 4 mm and 50% with probing depth ≥ 5 mm) and whole-genomic-amplified DNA was obtained. The DNA samples were subjected to amplification of a 16S rRNA gene fragment using universal bacterial primers, followed by DGGE analysis of the amplified gene sequences.

RESULTS

The non-HIV-infected group presented higher mean full-mouth visible supragingival biofilm (p = 0.004), bleeding on probing (p = 0.006), probing depth (p < 0.001) and clinical attachment level (p = 0.001) in comparison with the HIV-infected group. DGGE analysis revealed 81 distinct bands from all 33 individuals. Banding profiles revealed a higher diversity of the bacterial communities in the subgingival biofilm of HIV-infected patients with chronic periodontitis. Moreover, cluster and principal component analyses demonstrated that the bacterial community profiles differed between these two conditions. High interindividual and intra-individual variability in banding profiles were observed for both groups.

CONCLUSION

HIV-infected patients with chronic periodontitis present greater subgingival microbial diversity. In addition, the bacterial communities associated with HIV-infected and non-HIV-infected individuals are different in structure.

High prevalence of methicillin resistance and PVL genes among Staphylococcus aureus isolates from the nares and skin lesions of pediatric patients with atopic dermatitis

Staphylococcus aureus is highly prevalent among patients with atopic dermatitis (AD), and this pathogen may trigger and aggravate AD lesions. The aim of this study was to determine the prevalence of S. aureus in the nares of pediatric subjects and verify the phenotypic and molecular characteristics of the isolates in pediatric patients with AD. Isolates were tested for antimicrobial susceptibility, SCCmectyping, and Panton-Valentine Leukocidin (PVL) genes. Lineages were determined by pulsed-field gel electrophoresis and multilocus sequence typing (MLST). AD severity was assessed with the Scoring Atopic Dermatitis (SCORAD) index. Among 106 patients, 90 (85%) presented S. aureus isolates in their nares, and 8 also presented the pathogen in their skin infections. Two patients had two positive lesions, making a total of 10 S. aureusisolates from skin infections. Methicillin-resistant S. aureus(MRSA) was detected in 24 (26.6%) patients, and PVL genes were identified in 21 (23.3%), including 6 (75%) of the 8 patients with skin lesions but mainly in patients with severe and moderate SCORAD values (P=0.0095). All 24 MRSA isolates were susceptible to trimethoprim/sulfamethoxazole, while 8 isolates had a minimum inhibitory concentration (MIC) to mupirocin >1024 μg/mL. High lineage diversity was found among the isolates including USA1100/ST30, USA400/ST1, USA800/ST5, ST83, ST188, ST718, ST1635, and ST2791. There was a high prevalence of MRSA and PVL genes among the isolates recovered in this study. PVL genes were found mostly among patients with severe and moderate SCORAD values. These findings can help clinicians improve the therapies and strategies for the management of pediatric patients with AD.

Antimicrobial synergism against different lineages of methicillin-resistant Staphylococcus aureus carrying SCCmec IV

AIM

To evaluate the synergistic activity of antimicrobial drugs against lineages of methicillin-resistant Staphylococcus aureus (MRSA) carrying SCCmec IV. The biofilm production and related genes were also detected.

METHODS AND RESULTS

Forty two MRSA isolates were tested for biofilm production and related genes. Biofilm/biomass susceptibility to gentamicin (G), linezolid (L), rifampicin (R) and vancomycin (V) was determined for six isolates from three lineages prevalent in Rio de Janeiro hospitals in concentrations ranging from 0·25 to 64 μg ml(-1). Biomass was evaluated by microtitre plate test and number of viable cells (CFU cm(-2)) and inspected by epifluorescence microscopy. All isolates presented the icaA and sasG genes, but only 38% were biofilm producers. There were 50 and 45% biomass reductions when concentrations ≥4 μg ml(-1) of R or L and ≥16 μg ml(-1) of G or V, respectively, were used. Synergism tests produced a 55% biomass reduction with R(2μgml-1) + G(16μgml-1), R(2μgml-1) + L(2μgml-1), R(2μgml-1) + V(4μgml-1), and L(2μgml-1) + V(4μgml-1). Number of viable cells was reduced from 2 to 3 logs with R(2μgml-1) + L(2μgml-1) and R(2μgml-1) + V(4μgml-1).

CONCLUSIONS

Synergisms involving R plus L and R plus V caused important reductions in biofilm/biomass and the number of viable cells. Drug combinations should be considered in the chemotherapies of MRSA-SCCmec IV infections.

SIGNIFICANCE AND IMPACT OF THE STUDY

Biofilms in MRSA infections restrict the clinical choice of antimicrobials. Thus, knowledge of the best options for monotherapy and drug synergisms could improve clinical results.

Meticillin-resistant Staphylococcus aureus: spread of specific lineages among patients in different wards at a Brazilian teaching hospital

This study aimed to characterize meticillin-resistant Staphylococcus aureus (MRSA) lineages circulating in a Brazilian teaching hospital. MRSA isolates from nasal swabs were evaluated to assess antimicrobial susceptibility, staphylococcal cassette chromosome mec (SCCmec), Panton-Valentine leucocidin status, pulsed-field gel electrophoresis profile and multi-locus sequence type (MLST) analysis. Eighty-three MRSA isolates were analysed. SCCmec III (43.4%) and IV (49.4%) were predominant. ST1-IV (USA400) was more common in internal medicine (P = 0.002) whereas 'clone M' (SCCmec III) was more common in the medical and surgical intensive care unit (P = 0.004), and all isolates were ST5-IV (USA800) in dermatology (P < 0.001). These data improved the understanding of the MRSA epidemiology inside the hospital and helped to establish effective control measures.

Loss of lingual sensitivity and slightly increased size signaling schwannoma in a patient with mixed conjunctive tissue disease

The purpose of this study was to describe an unusual case of a lingual schwannoma associated with a mixed connective tissue disease (MCTD). A case report. A lingual schwannoma with loss of lingual sensitivity and slightly increased size in an 18-year-old patient with MCTD was correctly diagnosed through a biopsy and no reoccurrence was observed one year after the surgical removal of the tumor and sensitivity returned 3 months after surgery. This case was considered uncommon, making the clinical diagnosis challenging in view of the diversity of possibilities for its differential diagnosis, thus showing the importance of a biopsy to confirm the diagnosis and long term follow up in such cases.

Chromosomal location of retrotransposable REX 1 in the genomes in five Prochilodus (Teleostei: Characiformes

Transposable elements are repetitive DNA sequences comprising a group of segments able to move and carry sequences within the genome. Studies involving comparative genomics have revealed that most vertebrates have different populations of transposable elements with significant differences among species of the same lineage. Few studies have been conducted in fish, the most diverse group of vertebrates, with the objective to locate different types of transposable elements. Therefore, this study proposed to map the retrotransposable element Rex1 applying Fluorescent in situ Hybridization (FISH) in five species of the genus Prochilodus (Prochilodus argenteus, Prochilodus brevis, Prochilodus costatus, Prochilodus lineatus and Prochilodus nigricans). After the application of the Rex1 probe, scattered markings were found throughout the genome of analyzed species, and also the presence of small clusters located in the centromeric and telomeric regions coincident with the heterochromatin distribution pattern. This was the first description of the retrotransposable element Rex1 in Prochilodus genome seeking for a better understanding of the distribution pattern of these retrotransposons in the genome of teleost fish.

The first case report of non-nosocomial healthcare-associated infective endocarditis due to methicillin-resistant Staphylococcus aureus USA400 in Rio de Janeiro, Brazil

Staphylococcus aureus is the main causal pathogen of infective endocarditis (IE), which may have distinct origins, namely, community, nosocomial, or non-nosocomial healthcare-associated (NNHCA). We report the first case of NNHCA-IE caused by methicillin-resistant S. aureus strain USA400/SCCmec IV in which the combination therapy of rifampin and vancomycin had a favorable outcome for the patient.

Short communication: polymicrobial community in teeth associated with severe early-childhood caries

AIM

This was to characterise the microbial diversity in the complex dental plaque of children with severe early-childhood caries (S-ECC), using the denaturing gel gradient electrophoresis (DGGE) technique.

METHODS

The DGGE technique was used as a diagnostic tool to analyse samples from the oral cavity of a patient with S-ECC. Dental plaque samples from a 3-year-old child with S-ECC were taken from the primary central maxillary incisor (biofilm on vestibular surface), primary maxillary molar (biofilm on vestibular surface), primary central maxillary incisor (dentine), primary maxillary molar (dentine) and saliva and then analysed by PCR-DGGE.

RESULTS

Three bands occurred in all samples, moreover, 86% of similarity was observed in the pattern of bands between incisor and molar teeth biofilm samples, including four similar bands.

CONCLUSION

DGGE is a valuable tool for differentiating the microbial composition of the oral plaque in S-ECC children.

Transposable elements as a potential source for understanding the fish genome

Transposable elements are repetitive sequences with the capacity tomove inside of the genome. They constitute the majority of the eukaryotic genomes, and are extensively present in the human genome, representing more than 45% of the genome sequences. The knowledge of the origin and function of these elements in the fish genome is still reduced and fragmented, mainly with regard to its structure and organization in the chromosomes of the representatives of this biological group, with data currently available for very few species that represent the great variety of forms and existing diversity. Comparative analyses ascertain differences in the organization of such elements in the species studied up to the present. They can be part of the heterochromatic regions in some species or be spread throughout the genome in others. The main objective of the present revision is to discuss the aspects of the organization of transposable elements in the fish genome.

A new dispersed element in the genome of the catfish Hisonotus leucofrenatus (Teleostei: Siluriformes: Hypoptopomatinae)

Eight restriction enzymes were used in the prospection and isolation of repetitive sequences in the genome of the catfish Hisonotus leucofrenatus, a siluriform fish species that presents a large heterochromatic block in the W chromosome. In the tested enzymes, only the BamHI enzyme revealed a distinct band of 224 bp G+C value of 37%. In comparative analyses with sequences already available in the GenBank, the BamHI fragment sequence showed similarity with part of a Lepidoptera transposon. Fluorescent in situ hybridization (FISH) revealed that this sequence presents a dispersed pattern in the genome of H. leucofrenatus, forming clusters in some chromosome pairs in the pericentromeric region, which frequently are rich in constitutive heterochromatin. Based on the analysis performed, it can be inferred that the HLBam fragment constitutes a genomically dispersed transposon type element. It can be considered that the findings in this study can contribute to a better understanding of the organization and distribution of transposable elements in the genome of teleost fish.

Chromosome mapping of retrotransposable elements Rex1 and Rex3 in three fish species in the subfamily Hypoptopomatinae (Teleostei, Siluriformes, Loricariidae)

Transposons and retrotransposons represent a great portion of the eukaryotic genome. These repeated elements can be defined as genetic entities capable of self-inserting into different positions within the genome modifying the functions of the genes with which they are associated. The purpose of the present work was to isolate, identify, and map the sequences of Rex1 and Rex3 transposable elements present in the genomes of fishes of the family Loricariidae. The retrotransposable elements were identified through amplification with Rex1 and Rex3 primers, and the nucleotide composition of the retrotransposons was determined by automatic sequencing. In all the species analyzed it was possible to isolate Rex1 partial sequences from 520 to 563 bp in size and Rex3 partial sequences from 407 to 454 bp in size. Comparisons with the available literature showed that Loricariidae retrotransposons Rex1 and Rex3 have a high sequence similarity to putative homologous genes in different fish orders. Fluorescence in situ hybridization experiments conducted in 3 species, Hisonotus leucofrenatus, Pseudotocinclus tietensis, and Parotocinclus maculicauda, using the retrotransposable elements isolated for each species as probes, revealed that Rex1 and Rex3 share a similar dispersion pattern and are both found on all chromosomes of the 3 species organized in small clusters and dispersed on all the chromosomes, including euchromatic and heterochromatic regions, although a larger concentration was observed in the heterochromatic regions of H. leucofrenatus. The data found in the present study contradict much of the literature that substantiates that the retrotranspon elements are preferentially accumulated in the heterochromatin regions in fishes.

Molecular cytogenetic study of heterochromatin in Hisonotus leucofrenatus (Teleostei, Loricariidae, Hypoptopomatinae)

The fish species Hisonotus leucofrenatus exhibits a large amount of C-band positive segments with different responses after application of the C-banding technique. Type I class named herein appeared to be heavily stained after C-banding in the terminal position of five chromosome pairs and type II class, weakly stained after C-banding in the interstitial or pericentromeric position in nine chromosome pairs and in the supernumerary chromosomes. No variation was observed in type II C-band positive segments, however, type I segments displayed conspicuous polymorphisms, and six cytotypes were detected among the fish analyzed. Chromosomes were also analyzed by CMA(3) and DAPI staining, which showed that type I C-band positive segments comprised both AT-rich and GC-rich DNA, while type II segments were mainly composed of GC-rich sequences. HindIII-digested genomic DNA exhibits fragments of the ladder-like pattern, characteristic of tandemly arrayed repetitive sequences. Two of those fragments corresponding to monomeric and dimeric units of a 78 bp repetitive DNA sequence were cloned and sequenced. The cloned repetitive DNA was used as probe in fluorescent in situ hybridization experiments. The results revealed that these sequences were located in the same position as the type I C-band positive segments. This satellite DNA did not hybridize with DNA from other species of Hisonotus or from other fish of the family Loricariidae, suggesting that this sequence is specific to H. leucofrenatus. The role of these repetitive sequences in the karyotypic evolution of this species is discussed.

Improving oral absorption of Salmon calcitonin by trimyristin lipid nanoparticles

Solid lipid nanoparticles (SLN) composed of trimyristin (solid lipid) and poloxamer 407 (surfactant) were prepared by a w/o/w emulsion technique for the incorporation of Salmon calcitonin, and further explored as protein carriers for oral delivery. Trimyristin SLN showed a mean size diameter of 200 nm with an association efficiency for calcitonin of approx. 86%. The morphology of SLN was investigated by cryo-SEM and by AFM, revealing spheroid shape SLN with a smooth surface. The in vitro release of calcitonin occurred for a period of 8 h, under both gastric and intestinal simulated pH conditions, predicting suitable properties for oral administration. The pharmacological activity of the protein was evaluated following oral dosage of calcitonin-loaded SLN in rats. SLN lowered the basal blood calcium levels by up to 20% with 500 IU/kg dose sustaining hypocalcaemia over 8 h. The results indicate that incorporation of Salmon calcitonin into trimyristin SLN is a key factor for the improvement of the efficiency of such carriers for oral delivery of proteins.

Minoxidil-loaded nanostructured lipid carriers (NLC): characterization and rheological behaviour of topical formulations

Lipid nanoparticles are used as biocompatible carriers for several types of drugs intended for pharmaceutical, cosmetic, and biochemical purposes. The wide range of lipids and surfactants available for the production of such particles turns these carriers highly suitable for distinct applications (topical, dermal and transdermal, parenteral, pulmonary, and oral administration). This work describes the development of a special type of lipid particles, namely nanostructured lipid carriers (NLC), for minoxidil as an alternative to conventional topical alcoholic solutions. NLC were composed of stearic acid and oleic acid, being the matrix stabilized with poloxamer 188 in aqueous dispersion. To develop a suitable topical formulation, lipid dispersions were further mixed with freshly prepared Carbopol or perfluorocarbon based hydrogels. Minoxidil-loaded NLC were approximately 250 nm in size before the entrapment within the gel network and remained below 500 nm after mixing with both types of hydrogels. The occurrence of minoxidil crystallization in the aqueous phase of lipid dispersions was discarded under analysis by light microscopy and by scanning electron microscopy. Differential scanning calorimetry was used to assess the recrystallization index (i.e. measure of the percentage of lipid matrix that is crystallized) of the particles, which was shown to be 62% for minoxidil-free dispersions and 68% for minoxidil-loaded NLC dispersions. Rheological analysis of hydrogels containing NLC dispersions showed typical pseudoplastic behaviour which makes them suitable for topical purposes.

Insulin-loaded nanoparticles are prepared by alginate ionotropic pre-gelation followed by chitosan polyelectrolyte complexation

Alginate nanoparticles were prepared from dilute alginate sol by inducing a pre-gel with calcium counter ions, followed by polyelectrolyte complex coating with chitosan. Particles in the nanometer size range were obtained with 0.05% alginate and 0.9 mM Ca2+. The mean particle size was influenced by time and stirring speed of nanoparticle preparation, by alginate guluronic acid content and chitosan molecular weight and by the initial alginate:chitosan mass ratio. The association efficiency of insulin into alginate nanoparticles, as well as loading capacity were mainly influenced by the alginate:chitosan mass ratio. Under optimized size conditions, the association efficiency and loading capacities were as high as 92% and 14.3%, respectively. Approximately 50% of the protein was partially retained by the nanoparticles in gastric pH environment up to 24 hours while a more extensive release close to 75% was observed under intestinal pH conditions. Mild formulation conditions, optimum particle size range obtained, high insulin entrapment efficiency, and resistance to gastrointestinal release seem to be synergic and promising factors toward development of an oral insulin delivery form.

Probing insulin's secondary structure after entrapment into alginate/chitosan nanoparticles

The aim of the present study was to probe the structural integrity of insulin after being entrapped into chitosan/alginate nanoparticles produced by ionotropic polyelectrolyte pre-gelation. By manipulating the alginate:chitosan mass ratio and the pH during nanoparticle production, desired nanoparticles with a mean size of 850 (+/-88)nm and insulin association efficiency of 81 (+/-2)% were obtained. Insulin secondary structure was assessed by Fourier transform infrared (FTIR) and circular dichroism (CD) after entrapment into nanoparticles and after release from the particles under gastrointestinal simulated conditions. FTIR second-derivative spectra and area-overlap compared to an insulin standard confirmed that no significant conformational changes of insulin occurred in terms of alpha-helix and beta-sheet content. Far-UV-CD spectra corroborated the preservation of insulin structure during the nanoparticle production procedure. The presented nanoparticulate system is a promising carrier for insulin oral delivery since it preserves insulin structure and therefore also, potentially, its bioactivity.

Quinacrine female nonsurgical sterilization (QS): endometrial assessment by vaginal ultrasonography in 128 women

OBJECTIVE

Investigate effectiveness, safety and endometrial pattern after QS.

METHOD

This study began in March 1999 and ended March 18, 2003; 128 women received transcervical insertions of quinacrine. Follow-up visits with ultrasound were scheduled at 1, 3, 6, 12-month intervals.

RESULTS

Two pregnancies occurred, one at 25 months, the other at 37. Adverse events (AE) were: yellow vaginal discharge, headache, mild abdominal pain, vaginal pruritus, nausea and transient decrease in endometrial thickness. One patient had allergic reaction. A third insertion was done in case of vaginal bleeding (16.4%). One year after QS 10% still had amenorrhea, which may be the result of the fact that 73% of our patients had received DMPH. Once inside the uterus, the dissolved quinacrine could be seen within seconds, via ultrasound as a "Lake of Quinacrine" which stays for up to two hours. Frequently, a transverse vaginal ultrasonographic view of the uterine cavity showed plug-like echogenic points at the cornua.

CONCLUSION

Quinacrine sterilization is safe and effective. The echogenic points need to be more thoroughly studied in order to affirm whether ultrasonography may identify the blockage of the tubes. Since early pregnancy is due to imperfect tubal closure, the use of ultrasound may prevent failure. However, pregnancy due to later recanalization cannot be avoided.

Naproxen availability from variable-dose and weight sustained-release tablets

The aim of this work was to compare the naproxen availability from hydroxypropyl methylcellulose (HPMC) matrix tablets containing the same dose and a 2-fold weight variation (160 mg of naproxen in tablets weighting 250 and 500 mg) or with the same weight and a 2-fold dose variation (500 mg of weight and 160 or 320 mg of naproxen). The 2-fold weight variation in tablets with the same dose and also the 2-fold dose variation in tablets with the same weight did not affect the naproxen release. In addition, the release rate of two tablets of the same formulation and one tablet with a 2-fold dose and weight variation was not significantly different at the first minutes of the dissolution assay.

Effect of hydroxypropyl methylcellulose and hydrogenated castor oil on naproxen release from sustained-release tablets

The effect of the concentration of hydrophilic (hydroxypropyl methylcellulose [HPMC]) and hydrophobic (hydrogenated castor oil [HCO]) products, fillers (lactose and dibasic calcium phosphate), and buffers (sodium bicarbonate, calcium carbonate, and sodium citrate) on naproxen release rate was studied. Matrix tablets were prepared by double compression, and in vitro dissolution tests were performed. The dissolution results showed that an increased amount of HPMC or hydrogenated castor oil resulted in reduced drug release. The inclusion of buffers in the HPMC matrix tablets enhanced naproxen release. For HCO tablets, only sodium bicarbonate enhanced naproxen release. The presence of lactose on HPMC matrix tablets did not show a significantly different result from that obtained with the formulation containing dibasic calcium phosphate as a filler. However, for the tablets containing HCO, the presence of lactose significantly enhanced the naproxen release rate. The matrix-forming materials in this study were suitable for use in sustained-release tablets containing naproxen. The drug release can be modulated by adding suitable amounts of diluents and buffers.

Guidelines for the Department of Transportation physical examination

Primary care providers commonly perform the mandatory Department of Transportation Federal Highway Administration physical examination for individuals who drive commercial motor vehicles. Although these examinations may be offered at the worksite or in occupational health clinics, many drivers prefer to have them performed in the primary care setting. Performing the examination and subsequently certifying the driver is a highly regulated process with potentially serious consequences for the driver, the examiner, and the public. This article discusses the regulations and recommendations for certification of commercial drivers and the problems commonly encountered in the clinical setting.

[The cardiac toxicity of cancer chemotherapy]

The presence of secondary effects following the administration of chemotherapeutic drugs is an important limitation to cancer therapy. Of these, cardiotoxicity is of crucial importance due to its negative influence on survival. The anthracyclines and cyclophosphamide are the most important cardiotoxic antineoplastic agents currently used. If we agree on a ceiling dosage of chemotherapy we will deprive some patients with a highly functional cardiac reserve of a potential benefit in the control of their cancer. Other patients who are more susceptible to the cardiotoxic effects of anticancer agents will suffer from severe cardiac disfunction following small cumulative doses of anthracyclines. The authors discuss the main cardiotoxic effects of several antineoplastic drugs with special attention given to the anthracycline group. Several diagnostic methods potentially useful in cardiac monitoring are described. Radionuclide angiocardiography is considered the gold-standard in monitoring anthracycline cardiotoxicity. Other invasive methods like endomyocardial biopsy and right heart catheterization can be clinically useful when nuclear angiocardiography is inconclusive. The authors propose an approach to the prevention of anthracycline cardiotoxicity. Other chemotherapeutic agents like cyclophosphamide are associated with the presence of myopericarditis which is sometimes fatal. The cardiotoxic effects of anticancer treatment with 5-fluorouracil, mitoxantrone, carmustine, amsacrine and interferon are less frequent and usually more benign. Finally we discuss bone marrow transplantation and its related cardiotoxicity.