Differential effects of altered patterns of movement and strain on joint cell behaviour and skeletal morphogenesis.

OBJECTIVE: There is increasing evidence that joint shape is a potent predictor of osteoarthritis (OA) risk; yet the cellular events underpinning joint morphogenesis remain unclear. We sought to develop a genetically tractable animal model to study the events controlling joint morphogenesis. DESIGN: Zebrafish larvae were subjected to periods of flaccid paralysis, rigid paralysis or hyperactivity. Immunohistochemistry and transgenic reporters were used to monitor changes to muscle and cartilage. Finite Element Models were generated to investigate the mechanical conditions of rigid paralysis. Principal component analysis was used to test variations in skeletal morphology and metrics for shape, orientation and size were applied to describe cell behaviour. RESULTS: We show that flaccid and rigid paralysis and hypermobility affect cartilage element and joint shape. We describe differences between flaccid and rigid paralysis in regions showing high principal strain upon muscle contraction. We identify that altered shape and high strain occur in regions of cell differentiation and we show statistically significant changes to cell maturity occur in these regions in paralysed and hypermobile zebrafish. CONCLUSION: While flaccid and rigid paralysis and hypermobility affect skeletal morphogenesis they do so in subtly different ways. We show that some cartilage regions are unaffected in conditions such as rigid paralysis where static force is applied, whereas joint morphogenesis is perturbed by both flaccid and rigid paralysis; suggesting that joints require dynamic movement for accurate morphogenesis. A better understanding of how biomechanics impacts skeletal cell behaviour will improve our understanding of how foetal mechanics shape the developing joint.

Diversity and genetic parameter estimates for yield and its components in Jatropha curcas L.

Jatropha curcas L. is one of the most promising oilseeds for biodiesel and biokerosene production, but few basic studies or breeding programs have been conducted for the species. We estimated genetic parameters and diversity based on 10 yield traits in 77 half-sib progenies of J. curcas after 52 months in the field, and evaluated correlations between them and the oil content of the seeds. The mean grain yield per plant was 377.9 g (ranging from 169.8 to 772.1 g) and the mean oil content was 36.2% (ranging from 30 to 39.6%). Moderate estimates of heritability at the mean progeny level were obtained for the length of the fruit (84.7%), length (69.1%) and width (68.2%) of the seed, and grain yield per plant (62.2%). Oil content was only positively and significantly correlated with 100-seed weight. Our study revealed a range of possible crosses to be investigated in J. curcas. Progeny production should be evaluated over several crop seasons for the accurate selection of the best progenies.

The pollination ecology of a rare case of bee-pollinated Psittacanthus mistletoe.

The genus Psittacanthus (Loranthaceae) is widely distributed in the Neotropical region, where it is known for its large, colourful, scentless flowers. Until very recently, all Psittacanthus species were regarded as exclusively hummingbird-pollinated and the large species radiation in the genus attributed to the interactions with bird dispersers and pollinators. P. eucalyptifolius (Kunth) G.Don. is the only species reported as bee-pollinated. Here we describe the floral biology, floral visitors, and the reproductive system of P. eucalyptifolius in an Amazonian savanna, Brazil. We also compare the pollination success (reproductive performance) among different Psittacanthus species reported in previous studies. Psittacanthus eucalyptifolius produces sweet-scented flowers, and a small quantity of concentrated nectar. At least five species of scopate bees were recorded visiting and carrying pollen of P. eucalyptifolius. Xylocopa frontalis carried most pollen, visited more flowers, remained longer, and touched reproductive parts of flowers in >95% of the observed visits. Experiments indicate that P. eucalyptifolius is partially autocompatible (39% autonomous pollination) but depends on pollinators to achieve higher performance (~78% in control), indicating that bees can be as effective as birds in pollinating this group of mistletoes.

The use of non-surgical glue to repair perineal first-degree lacerations in normal birth: A non-inferiority randomised trial.

BACKGROUND AND PROBLEM: Surgical glue has been indicated for uncomplicated operatory wounds; however, it has a considerable cost. Non-surgical glue, a commercially available and cheaper product, has not been studied for repairing postpartum lacerations. AIM: To compare non-surgical glue to traditional sutures on perineal first-degree lacerations after normal birth. METHODS: In a prospective, open-label, non-inferiority, randomised controlled trial, we selected childbearing women who were admitted for normal term births and in whom skin lacerations occurred. They were assigned to laceration repair using either non-surgical glue (ethyl 2-cyanoacrylate; Glue group) or catgut sutures (Suture group). The primary endpoint was the occurrence of dehiscence >3mm. Secondary endpoints were procedure runtime, pain score, satisfaction level, and aspects of perineal repair by the REEDA score (hyperaemia, oedema, ecchymosis, exudation, and coaptation) immediately (T0), 24-48h (T1), and 7-10 days (T2) after childbirth. FINDINGS: We included 126 women, 63 in each group, and found a non-inferiority dehiscence rate in the Glue Group compared to the Control group (T1=1.6% vs. 1.6%, P=0.999 and P<0.001 for non-inferiority; and T2=2.2% vs. 4.3%, P=0.557). In the Glue Group, the procedure runtime was shorter, pain score was lower, and women's satisfaction was greater. No women had any allergic reaction in the study. CONCLUSIONS: Non-surgical glue was not inferior to traditional sutures to repair postpartum first-degree lacerations. In addition, non-surgical glue was associated with less pain and greater satisfaction. Brazilian Clinical Trials Registry (www.ensaiosclinicos.gov.br/rg/RBR-5Z8MKC).

Molecular epidemiology of hepatitis B virus in an isolated Afro-Brazilian community.

This study was conducted in an Afro-Brazilian, slave-descendant community with high (42.4%) hepatitis B virus (HBV) prevalence. Twenty (8.4%) out of the 239 subjects under study were HBsAg-positive, and HBV-DNA was detected in 59 (25%) individuals. A high rate (18.3%) of occult infection was therefore observed that was associated to low HBV loads (mean, 1.8 x 10(4) copies/ml) and to a specific amino acid substitution (C100Y) in the small surface antigen. Genotyping of 50 isolates showed that 43 (86%) were of subgenotype A1, one (2%) from subgenotype A2, and five (10%) from subgenotype D. Mixed genotypes A1 and E were observed in one (2%) sample. The genetic distance (0.8 +/- 0.3%) among the HBV/A1 isolates from the community was smaller than the intragroup divergence among A1 isolates from Brazil as a whole, but it was similar to that found between A2 isolates from different countries, suggesting that HBV/A1 was introduced in the community through different sources. The substitution W501R (polymerase), previously reported only in Gambia, was observed in 46% of the HBV/A1 isolates. The precore/core promoter region of HBsAg-positive isolates showed several substitutions that could explain the anti-HBe phenotype found in 18 of 20 (90%) of the HBsAg-positive subjects.

Nickel determination in saline matrices by ICP-AES after sorption on Amberlite XAD-2 loaded with PAN.

In the present paper, a solid phase extraction system for separation and preconcentration of nickel (ng g(-1)) in saline matrices is proposed. It is based on the adsorption of nickel(II) ions onto an Amberlite XAD-2 resin loaded with 1-(2-pyridylazo)-2-naphthol (PAN) reagent. Parameters such as the pH effect on the nickel extraction, the effect of flow rate and sample volume on the extraction, the sorption capacity of the loaded resin, the nickel desorption from the resin and the analytical characteristics of the procedure were studied. The results demonstrate that nickel(II) ions, in the concentration range 0.10-275 microg l(-1), and pH 6.0-11.5, contained in a sample volume of 25-250 ml, can be extracted by using 1 g Amberlite XAD-2 resin loaded with PAN reagent. The adsorbed nickel was eluted from the resin by using 5 ml 1 M hydrochloric acid solution. The extractor system has a sorption capacity of 1.87 mumol nickel per g of Amberlite XAD-2 resin loaded with PAN. The precision of the method, evaluated as the R.S.D. obtained after analyzing a series of seven replicates, was 3.9% for nickel in a concentration of 0.20 microg ml(-1). The proposed procedure was used for nickel determination in alkaline salts of analytical grade and table salt, using an inductively coupled plasma atomic emission spectroscopy technique (ICP-AES). The standard addition technique was used and the recoveries obtained revealed that the proposed procedure shows good accuracy.

Nosocomial spread of hepatitis B virus in two hemodialysis units, investigated by restriction fragment length polymorphism analysis.

A method for genotyping hepatitis B virus (HBV) strains, based on restriction fragment length polymorphism (RFLP) analysis of four different amplified fragments of the HBV genome, was used to investigate nosocomial infections that occurred in two Brazilian hemodialysis centers. Viral isolates from hepatitis B surface antigen (HBsAg)-positive serum samples from 27 hemodialysis patients and 39 HBV-positive unrelated control patients were grouped according to their RFLP patterns. Strains isolated from the control patients were divided into nine RFLP patterns: A1, A2, A3 (genotype A), D1, D2, D3, D4 (genotype D), F1, and F2 (genotype F). In hemodialysis unit A (Rio de Janeiro), 14 HBV isolates were grouped into five different RFLP patterns: A1, A2, A3, D3, and D4. Pattern A2, present at a relatively low prevalence (18%) in the control group, was observed in the majority (53%) of the hemodialysis patients. Notably, all five patients who seroconverted to HBsAg positivity in 1995 carried the strain A2. In hemodialysis unit B (state of São Paulo), where an outbreak of HBV infection occurred in 1996-1997, RFLP analysis showed that all 13 patients who seroconverted were infected with HBV isolates of genotype D. Coinfection with strain A1 was detected in seven of them. The results demonstrate the value of RFLP analysis in establishing common sources of infection in hemodialysis centers.

High proportion of subgroup A' (genotype A) among Brazilian isolates of Hepatitis B virus.

Hepatitis B virus (HBV) genotype A has been divided recently into two subgroups, designated A-A' (genotype A excluding A') and A'. Isolates belonging to subgroup A' have been identified in Africa. A new genotyping method, based on PCR amplification of the pre-S/S genome region and subsequent restriction fragment length polymorphism (RFLP) analysis, was developed, that established a correlation between RFLP subtypes and subgroups within genotype A. To investigate the occurrence of subgroup A' in South America, 119 Brazilian HBV isolates were analyzed. Ninety-three (78%) of them belonged to genotype A, with three predominating RFLP subtypes: 44 (37%) isolates were classified as AI, 30 (25%) were AII, and 18 (15%) were AIII. Pre-S/S nucleotide sequences of 15 genotype A isolates were determined. Phylogenetic analysis performed with these 15 and an additional 41 sequences revealed that isolates AI and AII clustered in subgroup A', whereas isolates AIII were classified into subgroup A-A'. The correlation RFLP subtypes-subgroups was confirmed by the presence of amino acid residues specific for subgroup A' in the surface antigens and polymerase of isolates AI and AII. The high proportion (63%) of isolates from subgroup A' suggested an African origin for a large number of Brazilian HBVs.

Copper determination in natural water samples by using FAAS after preconcentration onto amberlite XAD-2 loaded with calmagite.

A procedure for separation and preconcentration of trace amounts of copper in natural water samples, has been proposed. It is based on the adsorption of copper(II) ions onto a column of Amberlite XAD-2 resin loaded with calmagite reagent. This way amounts of copper within the range from 0.0125 to 25.0 microg, in a sample volume of 25 to 250 ml, and pH from 3.7 to 10.0 was concentrated as calmagite complex in a column of 0.50 g of Amberlite XAD-2 resin. Copper (II) ion was desorpted by using 5.0 ml of 2 mol l(-1) hydrochloric acid. Detection and determination limits of the proposed procedure for 250 ml sample volume were 0.15 and 0.50 microg l(-1), respectively. Selectivity test showed that (in the indicated concentration), calcium(II) (500 mg l(-1)), magnesium(II) (500 mg l(-1)), strontium(II) (50 mg l(-1)), iron(III) (10 mg l(-1)), nickel(II) (10 mg l(-1)), cobalt(II) (10 mg l(-1)), cadmium(II) (10 mg l(-1)) and lead(II) (10 mg l(-1)) did not interfere in copper determination by this procedure. Precision of the method, evaluated as the relative standard deviation by analyzing a series of seven replicates, was 2.42% for a copper mass of 1.0 microg in a sample volume of 100 ml. The accuracy of the proposed procedure was evaluated by means of copper determination in reference biological samples. The achieved results were in good agreement with certified values. The extractor system had a sorption capacity of 1.59 mumol of copper per gram of resin loaded with calmagite. The proposed procedure was applied for copper determination by FAAS in natural water samples. Samples were collected from different places of Salvador city, Bahia, Brazil. The achieved recovery, measured by the standard addition technique, showed that the proposed procedure had good accuracy. A good enrichment factor (50x) and simplicity are the main advantages in this analytical procedure.