Dose-dependent attenuation of heroin self-administration with lobeline

Behavioural studies have yielded results that show lobeline has the ability to attenuate d-methamphetamine self-administration. Further in vivo and in vitro studies have demonstrated a blockade of mu-opioid receptors with lobeline. The present investigation examined the ability of lobeline to attenuate heroin intravenous (i.v.) self-administration when administered prior to testing. Male Sprague-Dawley rats were surgically implanted with jugular catheters and trained to lever press for i.v. heroin infusions (18 microg/kg) under a fixed ratio-2 schedule wherein two active lever presses resulted in heroin delivery. Rats then were tested for heroin self-administration after pretreatment with subcutaneous lobeline injections (0.3, 1.0, or 3.0 mg/kg, 15 min prior to testing sessions). At doses of 1.0 and 3.0 mg/kg, lobeline attenuated self-administration of heroin. The results suggest a potential for lobeline to be used in pharmacotherapy for opioid abuse.

Energy consumption as a predictor test of the durability of a biological tissue employed in cardiac bioprosthesis

The mechanical behavior of the young bull pericardium in a fatigue test has been studied. This material is a similar tissue to those used in valve leaflet construction for a cardiac bioprosthesis. The consumed energy on each test was evaluated and afterwards used as a predictor of the biomaterial strength. Two-hundred and nine samples were tested to cyclical fatigue. The cut-off point to determine the sample quality was whether or not they resisted at least 4500 cycles. Only 22 samples withstood over that point (10.52%). The samples were classified according to their fatigue behavior in excellent, undefined and unsuitable. By using as a reference the consumed energy in the first 25 cycles, we could distinguish correctly (between 93.2 and 96.1%) the unsuitable material and most of the excellent (between 78.1 and 95.2%). From the rejected material 77% was really detachable and from the accepted, only 50% was excellent, with an equal methodology. The receiver operating characteristics curve was employed to establish decision levels when selecting samples, being 0.85 the best area (theoretical maximum value of 1). It is concluded that the energy wasted is a good predictor of the strength of the tissue. More than 90% of the unsuitable material and 50% of the excellent material (5% of all the material) is detected with this method.

Influence of the suture in the propagation of tears in calf pericardium employed in the construction of cardiac bioprostheses

The tearing of the fibers of biomaterials employed in implants or bioprostheses leads to early the failure of these devices. The purpose of this study was to determine the force necessary to propagate a tear in a biological tissue, calf pericardium, when sutured. We analyzed the outcome of 230 trials. There was a loss of resistance to tearing in samples sutured edge-to-edge as compared to unsutured control samples. This loss was not observed when the suture was preceded by an intact or protective zone. The values corresponding to the tearing force for an overlapping suture, especially when sewn with Gore-Tex(R), were higher than those obtained in controls. This study confirms the deleterious effect of the edge-to-edge suture, which can be minimized by protecting the suture, and the excellent behavior of the overlapping suture.

Testicular adrenal rest tumors and Leydig and Sertoli cell function in boys with classical congenital adrenal hyperplasia

CONTEXT

Infertility observed in adult males with congenital adrenal hyperplasia (CAH) has been associated with testicular adrenal rest tumors (TART) that may originate during childhood.

OBJECTIVE

Our objective was to describe the prevalence of TART and Sertoli and Leydig cell function in a group of boys aged 2-10 yr with CAH and to compare prevalence with that of a control group.

DESIGN

From August 2005 to January 2007, 19 patients with classical CAH (CAH group) were referred from seven endocrinology centers.

METHODS

We studied 19 subjects in the CAH group and, as a control group, 13 boys from the community that did not have testicular diseases. A complete physical exam was performed. High-resolution ultrasound was used to determine TART prevalence. Inhibin B and anti-Müllerian hormone were used as Sertoli cell markers. The ratio between basal testosterone levels and testosterone levels 72 h after beta-human chorionic gonadotropin (5000 U/m2) treatment [(T72- T0)/T0] was used to evaluate Leydig cell response.

RESULTS

CAH and control groups were comparable in chronological age (5.9 vs. 5.6 yr; P = 0.67) and bone age/chronological age ratio (1.09 vs. 1.03; P = 0.09). TART prevalence was four of 19 (21%) in the CAH group. Lower values for inhibin B (49.2. vs. 65.2 pg/ml; P = 0.018), anti-Müllerian hormone (70.1 vs. 94.2 ng/ml; P = 0.002), and (T72- T0)/T0 (5.6 vs. 13.6; P < 0.01) were observed in the CAH group.

CONCLUSION

TART in prepubertal males with classic CAH could be found during childhood. We also report differences in markers of gonadal function in a subgroup of patients, especially in those with inadequate control.

Incorporation of taurine and hypotaurine did not improve the efficiency of the Uppsala Equex II extender for dog semen freezing

The working hypothesis of the present study was that supplementation of the Uppsala Equex II (UE) extender with the amino acid (AA), taurine (T) and hypotaurine (H) would improve dog sperm post-thaw quality, as previously seen for ram and bull semen, respectively. Five pools from 15 ejaculates of 15 dogs were used. Each AA was added to the UE extender at a concentration of 25, 50 and 7 5mM. Amino acid-free extender was used as a control. The following post-thaw parameters were evaluated: sperm motility by light microscopy and by CASA evaluation, longevity, viability (eosin-nigrosin staining), and flow cytometry (FC) was used to assess acrosome integrity and mitochondrial activity after PI/Fitc-PSA and PI-Rhodamine staining, respectively. Post-thaw sperm motility and velocity did not differ among extenders. Amplitude of lateral head displacement was lower for sperm frozen in the 25 mM H-supplemented extender. Semen frozen in the extender with 50 mM of T resulted in higher number of live sperm with damaged acrosomes after thawing. Higher numbers of live sperm with minimal mitochondrial activity were obtained for samples frozen with 25 and 50 mM T-supplemented extenders. Semen frozen in the control and 50 mM T-supplemented extenders had the highest number of live (eosin-nigrosin stain negative) sperm immediately post-thawing. We concluded that supplementation of the Uppsala extender with T or H did not improve sperm post-thaw mitochondrial activity or semen motility and viability.

Durability of a cardiac valve leaflet made of calf pericardium: fatigue and energy consumption

We studied the mechanical behavior of membranes of calf pericardium, similar to those employed in prosthetic valve leaflets, when subjected to tensile fatigue. The objective was to assess its durability, as a fundamental property of cardiac bioprosthesis, and analyze the energy consumption. For this purpose, the authors built a hydraulic simulator to subject a spherical valve leaflet made of calf pericardium to cyclic stress mimicking cardiac function. A total of 522 assays were performed in 40 samples, subjected to cyclic pressures greater than 6 atm, and 482 subjected to pressures ranging between 2 and 6 atm. The mathematical expression that establishes the relationship between the pressure exerted and the frequency was obtained. If we assume that the function is continuous, this equation provides the range of fatigue tolerated for a given number of cycles. Using the optimal values (the five highest values per series), the expression was found to be y = 9.95x(-0 1214) (R(2) = 0.955), where x represents the frequency in cycles per second and y the pressure in atmospheres. In addition, we established the mathematical relationship between the energy consumed and the frequency, which was a function of the pressure exerted, regardless of the region or zone from which the samples had been obtained. The methods of manual and morphology-based selection employed produced widely dispersed results. When a mechanical criterion was included, the similarity in the energy consumed during fatigue testing markedly improved the correlation, with a coefficient of determination between paired samples of R(2) = 0.7477. A mechanical criterion, such as energy consumption, can help to improve sample selection and produce more consistent results. Finally, we obtained the mathematical expression that relates the energy consumed to the pressure exerted and the number of cycles per second to which the valve leaflet was subjected. This procedure enables us to establish the limit to the energy that a biomaterial can consume over a period of time during which it is subjected to a working pressure and, thus, calculate more precisely its durability.

Recovery rate, morphological quality and nuclear maturity of canine cumulus-oocyte complexes collected from anestrous or diestrous bitches of different ages

Canine cumulus-oocyte complexes (COC) were recovered from ovaries of post-pubertal animals (1-3, 4-6 and 7-10 years old) at different ovarian estrous phases (anestrus and diestrus). The number of COCs, and the number and nuclear maturity of high-quality (grade-1) oocytes were assessed. For all animals, no significant differences were found between the two reproductive phases relatively to the total number of COCs and grade-1 oocytes recovered. However, significant higher numbers of COCs were recovered from young than from elderly animals, and the proportion of grade-1 oocytes was also significantly higher in the younger group than in the other two age-groups. Of 226 grade-1 oocytes, 73% were at the germinal vesicle stage (GV), 10% had resumed meiosis (9% at germinal vesicle breakdown; 1% at metaphase-I) and 17% were degenerated. A significant effect of the reproductive phase on oocyte nuclear maturity was found only for adult animals, with a higher number of GV oocytes being found at anestrous (79%) due to higher rates of meiosis resumption (34%) at diestrous. The high number of grade-1 oocytes with meiosis resumption and fragmented or unidentified nuclear contents, indicates that current criteria for the selection of viable canine COCs are not optimized and need a new definition.

Hysteresis of a biomaterial: influence of sutures and biological adhesives

We studied the changes in energy consumption of samples of calf pericardium, when joined or not joined by sutures and adhesives, by means of hysteretic cycles. Sixty-four samples were subsequently subjected to tensile stress until rupture. An overlapping suture sewn in the form of a rectangle presented an acceptable mean resistance to rupture of over 10 MPa, although lower than the mean values in an unsutured control series where the mean resistance surpassed 15 MPa. The contribution of an acrylic adhesive to the resistance to rupture was negligible. The sutured samples that were reinforced with adhesives and had not been subjected to hysteretic cycles prior to rupture showed an anisotropic behavior. This behavior appeared to be lost in all the samples that underwent hysteretic cycles. We found an inflection point in the stress/strain curve following the stepwise increase in the load, with a value greater than and proximate to the final load applied. This inflection should be analyzed by means of microscopy. Finally, the mathematical relationship between the energy consumed and the stress applied, the strain or deformation produced and the number of cycles of hysteresis to which the samples were subjected was established as the ultimate objective of this study. The bonding systems provoked a greater consumption of energy, with the greatest consumption corresponding to the first cycle in all the series assayed. An equation relating the energy consumption in a sample to the number of hysteretic cycles to which it was subjected was obtained. Its asymptote on the x-axis indicates the energy consumption for a theoretical number of cycles, making it possible to estimate the durability of the sample.

CAALYX: a new generation of location-based services in healthcare

Recent advances in mobile positioning systems and telecommunications are providing the technology needed for the development of location-aware tele-care applications. This paper introduces CAALYX – Complete Ambient Assisted Living Experiment, an EU-funded project that aims at increasing older people's autonomy and self-confidence by developing a wearable light device capable of measuring specific vital signs of the elderly, detecting falls and location, and communicating automatically in real-time with his/her care provider in case of an emergency, wherever the older person happens to be, at home or outside.

Oral phaeohyphomycosis

This is the first description of solitary phaeohyphomycosis affecting the mucosal surface. The lesion developed in the inferior lip of a 57-year-old woman. After surgical resection, histopathological examination evidenced characteristic brownish fungal structures within granulomatous-purulent inflammation. Amplification and sequencing of rDNA obtained from paraffin-embedded tissue identified Alternaria species, as the causative agent.

Teaching Bovine Rectal Palpation with Live Cows in the Slaughterhouse: Is it Worthwhile?

Bovine rectal palpation, a procedure that requires considerable practice to develop the necessary skills, is often taught during extramural activities, or even learnt in practice after graduation. However, student access to cows in extramural activities may be limited because of student numbers, animal welfare considerations and concerns over induction of embryo mortality because of inexperience of the student. To overcome some of these limitations, in our school practical classes of bovine rectal palpation are taught in a slaughterhouse, with small groups of approximately 10 students per class, over a period of 30 weeks. Number of cows palpated, type of cases found and the success rate of students in the final practical exam were recorded and analysed for 3 years, and contrasted with the pre-established goals for the course. Additionally, a questionnaire was sent to former students to assess their opinion on the usefulness of the palpation course, as well as to identify main learning difficulties and collect suggestions to improve teaching methods. Overall, the information obtained indicated that the course is useful to teach palpation skills, even if the original goals may have been very optimistic. Most (96%) of the respondents had the opinion that the course was very useful or useful. Several suggestions were offered to improve teaching methods, but there was no consensus on a single recommendation. Despite the fact that a considerable number of respondents to the questionnaire did not use bovine rectal palpation in their practice, only one considered the classes 'not useful'. It is concluded that this method of teaching rectal palpation should be continued and the teaching methods improved with the adoption of some modifications.

Anti-Müllerian hormone (AMH/AMH) in the European sea bass: its gene structure, regulatory elements, and the expression of alternatively-spliced isoforms

In mammals, a multitude of studies have shown that anti-Müllerian hormone (AMH/AMH), apart from inducing Müllerian duct regression during male sexual differentiation, exerts inhibitory effects on male and female gonadal steroidogenesis and differentiation. However, in lower vertebrates like teleost fish, the function of AMH/AMH has been far less explored. As a first step to unravel its potential role in reproduction in teleost fish, we isolated and characterised the AMH gene in the European sea bass (sb), Dicentrachus labrax, determined putative regulatory elements of its 5'-flanking region, and analysed its gene expression and those of alternatively-spliced transcripts. The characterisation of sb-AMH revealed distinct features that distinguishes it from mammalian and bird AMH, suggesting a high rate of diversification of AMH during vertebrate evolution. It contained 7 exons that were divided by 6 introns, of which the last intron (intron vi) was localised only a few nucleotides upstream of the putative peptide cleavage site. The guanine and cytosine content of the open reading frame (ORF) was 52.7% and thus notably lower than that of bird and mammalian AMH. Sb-AMH cDNA was 2045 base pairs (bp) long, containing an ORF of 1599 bp encoding 533 amino acids. Deduced amino acid similarities of the conserved, carboxyterminal domain were highest with AMH in Japanese flounder (84.2%) and lowest with chicken AMH (45.5%). In the proximal promoter sequence of sb-AMH, a steroidogenic factor-1 (SF-1) binding site was present; however other regulatory sequences essential for transcriptional activation of AMH in mammals were absent. Likewise, there was no sequence homology to an SF3A2 sequence within the first 3200 bp upstream of the sb-AMH translation start site. Gene expression of sb-AMH and of alternatively-spliced sb-AMH transcripts were analysed in male and female juvenile and adult gonads as well as in somatic tissues of juvenile males. sb-AMH expression was highest in juvenile testis, but still remarkably high in juvenile ovaries and adult testis, as well as in brain, pituitary, and heart of juvenile male sea bass. Apart from adult ovary, levels of alternatively-spliced sb-AMHexonII/-99 were marginal in comparison with sb-AMH. In contrast, the transcript variant sb-AMHexonVII/+5 was expressed to a similar extent as sb-AMH in all tissues examined. The results of this work have provided the basis for future studies concerning the regulation and function of AMH/AMH in this species.

[Prolonged convulsions treated with buccal midazolam in a setting of mentally retarded patients with refractory epilepsy]

INTRODUCTION

Convulsive status epilepticus is a common major complication of epilepsy that results in high morbidity and mortality. Early treatment of prolonged seizures with rectal diazepam has been the method of choice in order to avoid this complication. However, several randomized trials in recent years suggest that buccal midazolam is as effective and safe as rectal diazepam. This study aims to seek further confirmation of the efficacy and safety of buccal midazolam in daily clinical practice.

METHOD

Ten out of 73 adult epileptic patients who were residents in a center for people with severe encephalopathy were included. We recorded all seizures over a one-year period. Prolonged seizures, defined as a seizure lasting one minute or longer, were treated by placing buccal midazolam 5 mg (1 ml) between the lower lip and the gum. We administered a second dose of midazolam when the seizure lasted more than two minutes and a third dose of midazolam, or a combination of rectal diazepam 5 mg together with midazolam, as a rescue therapy when the seizure lasted for more than 3 minutes. Vital constants were monitored.

RESULTS

We treated 52 prolonged seizures in 10 patients enrolled in the study. The treatment was effective with a single dose within two minutes in 80.7% of seizures. No cardiorespiratory complications were detected and no patients presented a convulsive status epilepticus.

CONCLUSION

Buccal midazolam is effective and safe in the treatment of prolonged seizures and has the advantage of being a convenient and socially acceptable administration form.

Stable expression of bioactive recombinant pleurocidin in a fish cell line

Pleurocidin (Ple), a linear cationic peptide of 25 amino acids, is a member of a larger family of antimicrobial peptides present in flatfish. Previous studies have shown that Ple displays a strong antimicrobial activity against a broad spectrum of bacteria and appears to play a role in innate host defence. In this work, the genomic sequence encoding the Ple prepropeptide has been isolated from Limanda limanda and cloned in a vector under the control of a non-viral promoter (the carp beta-actin promoter). By using this construction, expression of bioactive Ple was demonstrated in transformed fish cell lines continuously growing for more than 2 years. Furthermore, the study of Ple processing, maturation and secretion (by using fusion with green fluorescence protein) and the high bactericidal activity of the secreted recombinant Ple (detectable in cell supernatants without any concentration) are all reported here, as no other recombinant Ple or fish antimicrobial peptide have been expressed before to that extent. Such an overexpression of recombinant Ple or any other related antimicrobial peptide might improve the chances to develop new antibiotic agents, as well as to provide essential information about the mechanism of action, range of activity and the role in the innate immune response of antibiotic peptides.

A novel apical midpiece defect in the spermatozoa of a bull without an apparent decrease in motility and fertility. A case study

Despite some limitations as predictors of fertility, evaluation of sperm morphology and progressive motility is the commonest method to assess viability of frozen/thawed semen. In this article we describe by light and transmission electron microscopy a novel midpiece structural defect observed in 24-36% of frozen/thawed sperm cells from a Charolais bull, used in artificial insemination programs without any apparent ill effect to the fertility. After thawing, the sperm progressive motility ranged from 65 to 80% and the pregnancy rate for all artificial inseminations performed (43%) did not differ (p>0.05) from results obtained with insemination with semen of other bulls (40%). The defect consisted in mitochondrial aplasia at the neck region, mitochondrial segmental elongation and gaps and thickening of the outer dense fibers at the apical region of the midpiece, and loss of the cementing substance and development of plasma membrane extensions in the entire midpiece. No structural abnormalities were found in the capitulum, proximal centriole, striated columns, axoneme, annulus and fibrous sheath. The thickness of the outer fibers returned to normal at the distal region of the midpiece. Based on the examination it is suggested that the alterations might be originally caused by loss of the cementing substance that links mitochondria to the plasma membrane in association with mitochondrial aplasia at the neck region of the midpiece. The abnormality appeared not related to other described sperm defect syndromes, although it shared particular characteristics with the dag defect, segmental aplasia of the mitochondrial sheath, corkscrew defect and pseudodroplet defect.

Conformation- and fusion-defective mutations in the hypothetical phospholipid-binding and fusion peptides of viral hemorrhagic septicemia salmonid rhabdovirus protein G

Fourteen single and two double point mutants in the highly conserved region (positions 56 to 159) of the G gene of viral hemorrhagic septicaemia virus (VHSV), a salmonid rhabdovirus, were selected and obtained in plasmids by site-directed mutagenesis. Fish cell monolayers transfected with the mutant plasmids were then assayed for protein G (pG) expression, conformation-dependent monoclonal antibody (MAb) reactivity, and cell-cell fusion. Some mutations located in the phospholipid-binding p2 peptide (positions 82 to 110; mutants P86A, A96E, G98A, and R107A) abolished both MAb recognition and fusion activity, while others (P79A, L85S, and R103A) abolished MAb recognition but retained fusion at similar or lower pHs compared to those for the wild type. Phospholipid-binding assays of p2-derived synthetic peptides suggested that phosphatidylserine binding was not affected by the mutations studied. On the other hand, three (P79A, L85S, and T135E) of the four mutants retaining fusion activity mapped around two locations showing amino acid variation in 22 VHSV isolates and in neutralizing MAb-resistant mutants described previously. Mutations located in the hypothetical fusion peptide (positions 142 to 159; mutants F147K, P148K, and W154K) abolished both MAb recognition and fusion activity. The existence of mutants with altered conformation and defective fusion in both p2 and fusion peptides provides further evidence in favor of the participation of these and adjacent regions in some of the steps of the VHSV fusion processes, as suggested by previous studies. In addition, because the studied region induced strong immunological responses in trout, some of the mutants described here might be used to design attenuated VHSV vaccines.

Improvement of transfection efficiency of epithelioma papulosum cyprini carp cells by modification of cell cycle and use of an optimal promoter

Several methods to improve transfection of epithelioma papulosum cyprini (EPC) carp cells have been tested and are reported here. By modifying the cell cycle state of EPC cell monolayers and selecting the best promoter for the plasmid to be transfected, we increased transfection efficiency from 12.8% to 55.1% and decreased the coefficient of variation among different experiments from 54.1% to 11.8%. Thus 2- to 3-fold higher transfection efficiencies were obtained when the EPC monolayers were treated with colchicine or thymidine before transfection. In addition, the plasmids pMOKbetagal and its shorter derivative pMVC1.4betagal, both containing 218 bp of additional sequences upstream of the cytomegalovirus promoter contained in plasmid pCMVbeta, consistently produced higher transfection efficiencies than pCMVbeta. Combination of the two methods resulted in an improvement of both efficiency and reproducibility. These results should facilitate transfection of EPC cells to use as a model to obtain transgenics, to conduct quantitative transfected-cell fusion assays, to improve DNA-immersion-vaccination methods, or to obtain infectious cDNA from fish RNA viruses.

Characterisation of the syncytia formed by VHS salmonid rhabdovirus G gene transfected cells

Protein G expression and cell-to-cell fusion of cells transfected with the G gene of viral haemorrhagic septicaemia virus (VHSV) has been characterised. The presence of protein G in the membrane of transfected cells was confirmed by staining with Abs (Abs) and FACS. The subsequent formation of syncytia by membrane fusion of transfected cells required transfection with a wild type G gene and a low pH step. Mice Abs made against the protein G regions involved in fusion and neutralising monoclonal Abs (MAbs) as well as MAbs against some linear epitopes inhibited syncytia formation, thus confirming that syncytia formation was G-dependent. Similarly, Abs from trout immunised with purified VHSV or protein G inhibited syncytia formation whereas Abs from non-immunised or non-infected animals did not. Abs from mice or trout with the highest neutralisation titres also showed the highest percentage of inhibition of syncytia. While the main utility of these observations might be to further the understanding of the complex trout antibody response against VHSV and in the follow up of VHSV immunisation attempts, they may also have some future diagnostic potential for countries were work with VHSV is not allowed.

Determination of an optimized cut-off value for the Neospora agglutination test for serodiagnosis in cattle

A definitive diagnosis of neosporosis in cattle implies the examination of the aborted fetus. However, in many instances fetal material is not available. Therefore, most diagnosis are based on serological tests. At the moment, there are no consensuses about the cut-off for serodiagnosis of neosporosis in cattle, for any test. The objective of the present study was to estimate the best cut-off for the Neospora agglutination test (NAT) for serodiagnosis in cattle. For that purpose, 246 serum samples from 4 groups of dairy cows (aborted Neospora positive; not aborted healthy; aborted other diseases and herds endemic neosporosis) were collected and antibodies anti-N. caninum were determined by NAT. Additionally, immunoblot (IB) was performed with sera from all cows of the endemic neosporosis group and the patterns of seroreactivity were contrasted with the NAT titers for this group of cows. Evaluation of the optimized sensitivity and specificity was calculated using Youden's J-statistics. The best Youden's J-statistic was obtained at 1:40 titer, presenting 100% of sensitivity and 90.4% of specificity with negative and positive predictive values of 100 and 75.0%, respectively. The comparison between NAT titers and the IB banding pattern support the results of the statistical analysis, i.e. titers of 1:40 and higher showed a complex pattern of bands, while titers lower than 1:40 did not precipitate any bands. These results indicate that 1:40 was an optimized NAT cut-off for serodiagnosis in cattle.

The effects of diethylcarbamazine on the ultrastructure of microfilariae of Wuchereria bancrofti in vivo and in vitro

An ultrastructural study of microfilariae of Wuchereria bancrofti was performed after treatment in vitro and in vivo with diethylcarbamazine citrate (DEC). The morphological alterations produced by treatment in vitro with 5 micro g/ml of DEC were the loss of microfilarial sheaths and lysis of the cytoplasm, with the destruction of all organelles and the formation of several vacuoles, the contents of which presented various degrees of electron-density, or showed an empty appearance. Some of these vacuoles seemed to be extruding from the cytoplasm as apoptotic bodies and others presented organelles inside. Similar alterations were observed after in vivo treatment. At 40 min after treatment of a microfilaremic individual with DEC, almost all microfilariae observed had lost their sheaths; and, in some of them, remains of the microfilarial sheath on the larval surface could be detected. Numerous vacuoles were observed, mainly in the hypodermis and somatic cells, showing organelles inside or an empty appearance. Condensed chromatin was also observed in some somatic cells. At 1 h after treatment of a microfilemic individual with DEC, microfilariae presented drastic morphological alterations, with large vacuoles within somatic cell cytoplasm and complete lysis of all cellular organelles. Therefore, both treatments with DEC in vitro and in vivo had a direct mechanism of action on the microfilariae of W. bancrofti, including organelle damage and apoptosis.

Reversible inhibition of spreading of in vitro infection and imbalance of viral protein accumulation at low pH in viral hemorrhagic septicemia rhabdovirus, a salmonid rhabdovirus

The inhibition of viral hemorrhagic septicemia rhabdovirus (VHSV) in vitro infection by pHs of <7 (low pH) has been previously reported. Nevertheless, the details of the mechanism underlying this effect remain obscure. We present evidence showing that low-pH inhibition occurs during a viral postadsorption step. Thus, while VHSV bound, replicated within single cells, and presented its G protein on the membranes of infected cells at both low and physiological pHs, both cell-to-cell spreading of infection (as estimated by the appearance of foci of infected cells) and fusion (as estimated by a syncytium assay) were inhibited by this low pH. The decreased VHSV titers and the inhibition of both cell-to-cell spreading of infection and fusion could be reversed by adjusting the pH to 7.5 at any time during infection. This effect should be taken into account to avoid false negatives in the diagnosis of VHSV by cell culture. On the other hand, the cell-to-cell spreading of infection at pH 7.5 could be stopped at any time by reducing the pH to 6.5. Since at low pH there were changes in the protein G conformation and smaller and imbalanced amounts of N with respect to M1, M2, and G viral proteins, alterations of the assembly and/or budding of VHSV are most probably involved in the absence of newly released infective virions.

Application of inducible and targeted gene strategies to produce transgenic fish: a review

Compared to mammals, fishes offer easier transgenic technology because each female produces hundreds of eggs, the manipulated embryos do not need to be incubated inside the mother, and the probability of their harboring human-related pathogens is lower. In the last 15 years, traditional methods using injections of fertilized fish eggs and strong viral promoters have resulted in the generation of many transgenic fish species; however, they showed random genome integration with some mosaicism and episomic expression. The use of inducible gene systems that control temporal and tissue expression and of gene-targeting methodologies based on homologous recombination is desirable to control the expression, efficiency of insertion, and locus of incorporation of transgenes into fish genomes. A variety of systems developed for mammals are now available to be tested in fishes. The use of such systems would require further development of stem cell or nuclear transplant technologies in fish. Most of that work remains to be explored.

Comparative study of the mechanical behaviour of a cyanoacrylate and a bioadhesive

We compared the mechanical resistance of 18 samples of calf pericardium bonded with a 100 mm2 overlap, by two types of glues: a cyanoacrylate (Loctite 4011) and a bioadhesive (BioGlue). Comparative tensile testing was also carried out in 40 paired samples, 20 bonded with the cyanoacrylate and 20 unbonded controls. The findings at rupture showed a greater resistance of the calf pericardium glued with cyanoacrylate, with a mean tensile strength of 0.15 MPa vs. 0.04 MPa for the biological glue (p= 0.000). They also demonstrated a loss of resistance of the samples bonded with cyanoacrylate when compared with that of the unbonded other halves of the pairs: 0.20 MPa and 0.27 MPa vs. 19.47 MPa and 24.44 MPa (p < 0.001). The method of selection by means of paired samples made it possible to establish the equations that relate the stress and strain, or deformation, with excellent coefficients of determination (R2). These equations demonstrate the marked elastic behaviour of the bonded samples. Moreover, these findings show the cyanoacrylate to be superior to the biological glue, leading to the examination of the compatibility, inalterability over time and mechanical behaviour of the cyanoacrylate in sutured samples, as well as the study of the anisotropy of the biomaterial when bonded with a bioadhesive.

Sutured calf pericardium: influence of the type and angle of the suture on mechanical behavior

Careful selection of the biological tissue to be used in cardiac bioprostheses and a thorough knowledge of its mechanical behavior, facilitating both the prediction of this behavior and the interactions between the tissue and the other materials employed, is the best approach to designing a durable implant. For this purpose, a study involving uniaxial tensile testing of calf pericardium was carried out. Two sets of three contiguous strips of tissue were obtained from each pericardial membrane, to perform a total of 144 trials. Two samples were sewn with one of four commercially available suture materials: Gore-Tex, nylon, Prolene and silk. In each set of three samples, the center strip remained intact and unsutured to serve as a control, while the left-hand strip was sutured at a 45 degrees angle with respect to the longitudinal axis and the right-hand strip was sewn at a 90 degrees angle. All the samples were tested until rupture. The results demonstrated a significant loss of mean load (p<0.01) in the sutured samples at rupture. The angle of the suture had no influence on these results, although the stress/strain curves showed that, as the tensile stress increased, the mechanical behaviors were less uniform. The rupture of the collagen fibers could explain this phenomenon. The pericardium sutured with Gore-Tex presented a greater strain, or deformation (elongation), at lower levels of stress, regardless of the angle of the suture. The tissue selection criteria, based on the use of paired samples, enabled a correct prediction of the mechanical behavior of the tissue, with excellent correlation coefficients (>0.98) and a high degree of homogeneity in the results.

Comparison of the mechanical behaviors of biological tissues subjected to uniaxial tensile testing: pig, calf and ostrich pericardium sutured with Gore-Tex

The purpose of this study was to compare the mechanical behavior of calf pericardium, pig pericardium and ostrich pericardium when subjected to tensile testing. Tensile stress was applied to 108 tissue samples, 36 of each type of tissue, until rupture. Groups of three adjacent strips measuring 12 x 2 cm(2) were cut longitudinally. Each group consisted of an unsutured center sample, or control, and the two contiguous samples, that on the right sutured with Gore-Tex at a 90 degrees angle with respect to the longitudinal axis and that on the left sewn with the same suture material at 45 degrees angle. The sutured samples showed a statistically significant loss of resistance (p<0.001) when compared with the corresponding unsutured tissue. The mean stresses at rupture for sutured ostrich pericardium were 21.81 and 20.81 MPa in the samples sewn at 45 degrees and 90 degrees, respectively, higher than those corresponding to unsutured calf and pig pericardium, 14.0 and 11.49 MPa, respectively, at rupture. The analysis of the stress/strain curve shows a smaller difference between sutured and unsutured ostrich pericardium than those observed in the other two biomaterials. These results demonstrate that, in addition to its greater resistance, ostrich pericardium also presents a less pronounced interaction with the suture material. Its capacity to absorb the shearing stress produced by the suture is greater. This report also confirms that the method of selection using paired samples ensures their homogeneity and makes it possible to predict the behavior of a sample by determining that of the other half of the pair.

Environmental factors have little influence on the reproductive activity of the Iberian hare (Lepus granatensis)

The two European hare species with the largest ranges, the brown hare (Lepus europaeus) and the mountain hare (L. timidus), have a marked seasonal pattern of reproduction, probably reflecting strong environmental influences during the year. In this work, we evaluate the role of some environmental factors on the reproductive activity of another European hare species, the Iberian hare (L. granatensis). The study was carried out in Pancas, southern Portugal, from mid-1997 through December 1999. Climatic data (mean monthly values of minimum and maximum air temperature, daylength and total monthly rainfall) were recorded at the nearest meteorological station. To assess abundance and quality of food, samples of the herbaceous vegetation were collected every two months and analysed for water, fibre and crude protein content. Iberian hares were collected every two months and live or post mortem analyses were performed. The proportion of males with external testes and of pregnant females as well as the weight of the gonads were recorded. While environmental variables had marked seasonal variations, the Iberian hare nevertheless showed continuous reproductive activity. In all sampled periods, males with external testes and pregnant females were observed. However, a slight decrease of sexual activity appears to occur, mainly in males, during autumn. Only the variation of male reproductive characteristics was significantly explained by multiple regression equations. Maximum regression coefficients were obtained with the climatic variables (minimum, maximum temperatures and daylength) and vegetation biomass of the preceding two months. Our data indicate that environmental factors have little effect on reproduction in the Iberian hare. The results are compared with those obtained for other phylogenetically and geographically close hare species, and with another leporid, the wild rabbit (Oryctolagus cuniculus algirus), which occurs sympatrically with L. granatensis.

Localisation and distribution of Wuchereria bancrofti antigens recognised by antisera from tropical pulmonary eosinophilia and from individuals with intestinal helminths

Serological analyses of sera from patients with a typical picture of filarial tropical pulmonary eosinophilia (TPE) and sera from patients from a region non-endemic for filariasis harbouring intestinal helminths, as Ascaris lumbricoides and Strongyloids stercoralis, revealed equally high titers of IgG4, usually considered diagnostic for filariasis. Ultrathin sections of adult worms of W. bancrofti embedded in the hydrophilic resin L.R. White were incubated with sera from patients with a typical picture of filarial tropical pulmonary eosinophilia (TPE) and sera from patients of a region that was non-endemic for filarial TPE but endemic for intestinal helminths. Both groups had a similar pattern of labelling, except that the labelling intensity was higher with the sera of patients with filarial TPE. The present study indicates relevant epitopes recognised by sera from TPE-patients and also individuals with intestinal helminths in all tissues of adult and intra-uterine microfilaria of W. bancrofti, instead of being localised in a specific nematode region. These findings suggest that people from areas not endemic for filariasis, but who harbour intestinal helminths, also share antifilarial antibodies in their serum that recognise antigens of adult worms and intrauterine microfilaria of W. bancrofti.

Isolation of viable Toxoplasma gondii from naturally infected aborted bovine fetuses

Neospora caninum and Toxoplasma gondii are related parasites. The former is a common cause of abortion in dairy cattle. The latter has not been conclusively demonstrated in bovine fetuses. During the course of attempts to isolate N. caninum from aborted fetuses, T. gondii was isolated from 2 aborted fetuses, 1 from Portugal and 1 from the United States. Both isolates were made by bioassay of fetal brains in mice. The fetus from Portugal was about 5 mo in gestational age, and the fetus from the United States was a full-term stillborn.

Salmonid viral haemorrhagic septicaemia virus: fusion-related enhancement of virus infectivity by peptides derived from viral glycoprotein G or a combinatorial library

To search for enhancers and/or inhibitors of viral haemorrhagic septicaemia virus (VHSV, a salmonid rhabdovirus) infectivity, a total of 51 peptides from a pepscan of viral envelope protein G, a recombinant peptide from protein G (frg11) and 80 peptide mixtures from an alpha-helix-favoured combinatorial library were screened. However, contrary to what occurs in many other enveloped viruses, only peptides enhancing rather than inhibiting VHSV infectivity were found. Because some of the enhancer pepscan G peptides and frg11 were derived from phospholipid-binding or fusion-related regions identified previously, it was suggested that enhancement of virus infectivity might be related to virus-cell fusion. Furthermore, enhancement was significant only when the viral peptides were pre-incubated with VHSV at the optimal low pH of fusion, before being adjusted to physiological pH and assayed for infectivity. Enhancement of VHSV infectivity caused by the pre-incubation of VHSV with peptide p5 (SAAEASAKATAEATAKG), one of the individual enhancer peptides defined from the screening of the combinatorial library, was independent of the pre-incubation pH. However, it was also related to fusion because the binding of p5 to protein G induced VHSV to bypass the endosome pathway of infection and reduced the low-pH threshold of fusion, thus suggesting an alternative virus entry pathway for p5-VHSV complexes. Further investigations into VHSV enhancer peptides might shed some light on the mechanisms of VHSV fusion.

Mechanical behavior of chemically treated ostrich pericardium subjected to uniaxial tensile testing: influence of the suture

The mechanical behavior of sutured ostrich pericardium was studied by uniaxial tensile testing. One hundred forty-four tissue specimens were assessed: 96 sutured samples (48 in which a centrally located suture was placed at an angle of 90 degrees with respect to the longitudinal axis, whereas in the remaining 48, a centrally located suture was placed at a 45 degrees angle to the longitudinal axis, in sets of 12 samples each, sewn with sutures made of Gore-Tex, nylon, Prolene, or silk), and 48 unsutured controls. Each group of 24 samples sewn at one angle or the other with the different suture materials was assayed together with a corresponding control group of 12 unsutured samples. The mean tensile strengths in the unsutured controls ranged between 30.16 MPa and 43.42 MPa, whereas those of the sutured sets ranged from 14.68 MPa to 21.91 MPa. The latter presented a statistically significant loss of resistance (p < 0.01) when compared with the unsutured tissue samples. The angle of the suture with respect to the longitudinal axis influenced the degree of shear stress produced by the suture, as well as the behavior of the different suture materials used. The set of samples sewn with Prolene appeared to be that most sensitive to changes in the angle of the suture, whereas tissue sewn at a 45 degrees angle with Gore-Tex presented lower shear stress values in comparison with samples in which the other three materials were used. A method of tissue selection based on morphological and mechanical criteria was used to ensure the homogeneity of the results in such a way that the coefficients of determination (R2) for the stress/strain curve fitting equation ranged between 0.888 and 0.995. This excellent fit made it possible, applying regression analysis, to predict the mechanical behavior of a specimen by determining that of a contiguous tissue sample. Thus, it should be possible, at least theoretically, to characterize the behavior of a specific region or zone of the biomaterial. In conclusion, ostrich pericardium exhibits strong resistance to rupture, even when sutured. The selection method used ensures the homogeneity of the samples and, thus, of the results. The angle of the suture with respect to the longitudinal axis, where the load is centered, determines the shear stress produced by the suture and the mechanical behavior of each suture material.

The telescoping suture--Part 1: Does this technique improve the mechanical behavior of a biomaterial?: Calf pericardium

The authors study the mechanical behavior of calf pericardium employed in the construction of cardiac valve leaflets when subjected to telescoping suture, followed by tensile stress until rupture. One hundred twenty pericardial tissue samples were employed, 60 cut from root-to-apex and another 60 cut in transverse direction. Each of these two groups consisted of 12 control samples that were left unsutured and four sets of 12 samples each that were rejoined by telescoping suture using silk, Prolene, nylon or Gore-Tex., and subjected to tensile stress. At the rupture of the sutured tissues, the tensile stress of the suture materials ranged between 57.54 MPa for the series sewn lengthwise with Gore-tex and 114.08 MPa for the series sewn crosswise with silk. At these levels of stress, the deformation of the suture thread was much less marked than that of the calf pericardium, and internal stresses were produced that were difficult for the biomaterial to absorb. There was a loss of real load in all the sutured series when the observed resistance to rupture, expressed in kilograms, was compared with the estimated value. This loss of resistance did not invalidate the telescoping suture technique since the resistance to rupture was still much greater than that associated with suturing the two edges of the cut pericardium together. This report confirms the deleterious role of the shear force generated in the pericardium by the suture.

The telescoping suture--Part II: A novel method to improve the mechanical behavior of a new biomaterial: ostrich pericardium

Ostrich pericardium, sutured using a telescoping or overlapping technique, was studied to determine its mechanical behavior. From each of 12 pericardial sacs, four contiguous strips were cut longitudinally, from root to apex, and another four contiguous strips were cut in transverse direction. One of the strips in each set of four was used as an unsutured control and the remaining three were sutured by overlapping 0.5 cm of the tissue and sewing with Gore-tex, Prolene or Pronova. These 96 samples were then subjected to tensile testing along their major axes until rupture. The tensile stresses recorded in the suture materials at the moment tears appeared in the pericardium ranged between 55.99 MPa and 70.23 MPa for Gore-tex in samples cut in the two directions. Shear stress became ostensible at 56 MPa, with clearly evident tears. However, microfracture of the collagen fibers must be produced at much lower stress levels. The comparison of the resistance in kilograms (machine-imposed), without taking into account the sections in which the load was applied, demonstrated only a slight loss of load when the telescoping suture was employed in ostrich pericardium samples. Ostrich pericardium may continue to be an alternative biological material for the construction of heart valve leaflets.

Antibody response to a fragment of the protein G of VHS rhabdovirus in immunised trout

A fragment (called frg#11, amino acids, aa 56-110) of the protein G (pG) of viral haemorrhagic septicaemia virus (VHSV) was designed after previous results showed it to be recognised by approximately 40% of the trout immunised to VHSV [Dis. Aquat. Organ. 34 (1999) 167]. frg#11 was then cloned, expressed, purified and used to study the production of antibodies to its epitopes in trout immunised to VHSV. Anti-frg#11 trout antibodies could be detected in serum from individual trout surviving VHSV exposure, immunised by injection with purified VHSV or DNA-immunised with its pG gene whereas it was not detected in non-infected and non-immunised trout. The trout serum antibodies which reacted more strongly by ELISA using solid-phase frg#11 (continuous or linear epitopes on the sequence of the pG) had the lowest VHSV-neutralising activity (epitopes which are pG conformation-dependent). Because antibodies recognising continuous as well as conformation-dependent epitopes of the pG seem to be involved in protective trout immunological responses to VHSV, the estimation of anti-frg#11 antibodies could help to the dissection of the complex trout antibody response to VHSV infections. In addition, these preliminary results suggest that the determination of anti-frg#11 antibodies might also be used to complement in vitro viral neutralising assays which seem to be restricted to pG conformation-dependent epitopes.

Mechanical effects of increases in the load applied in uniaxial and biaxial tensile testing. Part II. Porcine pericardium

The mechanical behavior of porcine pericardium was analyzed to compare it with that of calf pericardium employed in valve leaflets for cardiac bioprostheses. Forty samples of pericardium were subjected to uniaxial tensile testing, 20 as controls and 20 exposed to loads increasing stepwise from 0.5 to 1.5 kg and to 3 kg, and thereafter to rupture, with a return to zero load between each new increment. Another 20 samples were used in biaxial tensile tests involving the application of loads increasing stepwise (to 0.5, 1.5, 3 and 5 kg) until rupture with a zero-load interval before each increment. The ultimate stresses were very similar, showing no statistically significant differences when compared in terms of type of assay, controls and study samples or region of pericardial tissue being tested. In the stepwise biaxial assays, the mean stresses at rupture were also very homogeneous. Using morphological and mechanical criteria for sample selection, it was possible to obtain mathematical fits for the stress/strain relationship, with excellent coefficients of determination. The relationship between the area under the stress/strain curve and the load applied or the strain observed was also studied in the biaxial assay as an equivalent to the cycles of hysteresis produced in the test. The increment in the area under the curve (the energy consumed) may be a good parameter for assessing the changes in the collagen fiber architecture of the pericardial tissue, changes that may help to detect early failure.

Immunocytochemical localization of antigens recognised by tropical pulmonary eosinophilia and individuals with intestinal helminths antisera in microfilaria of Wuchereria bancrofti

Ultrathin sections of microfilaria of W. bancrofti embedded in the hydrophilic resin L.R. White were incubated with sera from patients with a typical picture of filarial tropical pulmonary eosinophilia (TPE) and sera from patients of a non-endemic region for filariasis regarding intestinal helminths. Both groups had a similar pattern of labelling, except that the labelling intensity was higher with the sera of patients with filarial TPE. The present study indicates relevant epitopes recognised by sera from TPE-patients and also individuals with intestinal helminths in all tissues of microfilaria of W. bancrofti, instead of being localised in a specific nematode region. These findings suggest that sera from people from an area not endemic for filaria, harbouring intestinal helminths, also share antifilarial antibodies that recognise antigens of microfilaria of W. bancrofti.

Mechanical effects of increases in the load applied in uniaxial and biaxial tensile testing: Part I. Calf pericardium

The authors analyzed the mechanical behavior of the calf pericardium employed in the construction of valve leaflets for cardiac bioprostheses. Forty samples of pericardium were subjected to uniaxial tensile testing, 20 as controls and 20 exposed to loads increasing stepwise until rupture, with a return to zero load between each new increment. Another 20 samples were used similarly in biaxial tensile tests involving loads increasing stepwise until rupture, again returning to zero load between steps. The ultimate stresses in the uniaxial study were very similar and were not influenced by the region of pericardial tissue being tested or the increments in load to which the tissue was exposed. The mean stresses at rupture in the stepwise biaxial assays were significantly greater (p<0.01). Using morphological and mechanical criteria for sample selection, it was possible to obtain mathematical fits for the stress/strain relationship in both types of assays, with excellent coefficients of determination (R (2)>0.90). In uniaxial tests in which the selection criteria were not applied, the correlation improved as the load increased, a phenomenon that did not occur in the biaxial studies. The values varied throughout the different cycles, adopting exponential forms when the strain was greatest. These variations, which demonstrate that the increase in the energy consumed is a function of the stress applied and of the strain produced, should be good parameters for assessing the changes in the collagen fiber architecture of pericardial tissue subjected to cyclic stress, and may help to detect early failure.

Improvement of DNA transfection with cationic liposomes

The increasing use of cationic liposomes as vectors for DNA transfection of eukaryotic cells is due to its high efficiency and reproducibility. After the interaction of the DNA cationic-liposome complexes (DNA-CLC) with the plasma membrane, the entry into the cells delivers the DNA-CLC to the endosome-lysosome pathway where some of the DNA-CLC are degraded. The non-degraded DNA that escapes to the cytoplasm, still has to transverse the nuclear membrane to be transcribed and then translated. To improve the efficiency of the whole process, we can manipulate the DNA (sequences, promoters, enhancers, nuclear localisation signals, etc), the DNA-CLC (lipids) or the plasmatic, endosomal and/or nuclear cellular membranes (ultrasound, electroporation, Ca++, pH of the endosomes, mitosis, fusogenic peptides, nuclear localisation signals, etc). Most of these methods have been generally used individually but in combination, may greatly improve the efficiency and reproducibility of in vitro transfection. While much of this work remains yet to be done and present results further explored, the application of these efforts is essential to the future development of new gene therapy strategies.

Seasonal variation in the reproductive activity of the wild rabbit (Oryctolagus cuniculus algirus) in a Mediterranean ecosystem

To establish a successful strategy for managing wild rabbit (Oryctolagus cuniculus algirus) populations it is essential to have a clear understanding of reproductive biology. In Portugal, previous work suggested a seasonal pattern of reproductive activity for this species. In this study we present additional information on the seasonal reproductive activity of the wild rabbit as well as data on the influence that environmental factors have on the onset and length of the breeding season. The study was carried out in Pancas, southern Portugal, from October 1997 to September 1998. Rabbits were collected every two months and post mortem analyses were performed. In the males, circulating concentration of testosterone, gonadal weight, daily sperm production, diameter of the seminiferous tubules and the thickness of epithelial cells were measured. The numbers of corpora lutea, embryos and placental scars were recorded in the females. To assess abundance and quality of food, samples of herbaceous vegetation were collected and analysed for water, fibre and crude protein content. The reproductive season extended from November to June with a peak in March/April, with both sexes showing an annual cycle of gonadal development and subsequent regression. All analysed females were pregnant and/or lactating between March and June. The mean litter size estimated by counting the embryos in the uteri was 3.90 ± 0.50. Daily sperm production was highest between November and April. Testicular function was strongly correlated with environmental temperature and the water content of the vegetation, and both testicular and ovarian development were correlated with vegetation biomass.

Stereoselective analysis of fluvastatin in human plasma for pharmacokinetic studies

Fluvastatin, an inhibitor of cholesterol biosynthesis, is commercialized as a racemic mixture of the (+)-3R,5S and (-)-3S,5R stereoisomers, although inhibition of HMG-CoA reductase mainly resides in the (+)-(3R,5S)-fluvastatin isomer. The aim of the present study was to analyze fluvastatin isomers in human plasma with application to studies on kinetic disposition. Plasma samples of 1 ml were eluted into 3 ml LC-18 Supelclean (Supelco) columns equilibrated with methanol and water. The columns were washed with water and acetonitrile and then eluted with methanol containing 0.2% diethylamine. The (+)-3R,5S and (-)-3S,5R isomers were separated by HPLC on a Chiralcel OD-H chiral phase column and detected by fluorescence (lambda(ex) 305 nm; lambda(em) 390 nm). The quantification limit was 0.75 ng for each isomer/ml plasma and linearity was observed up to 625 ng/ml. The relative standard deviations obtained for intra- and inter-assay precision were lower than 10% and the recovery was higher than 80% for both enantiomers. Application of the method to a stereoselective study on the pharmacokinetics of fluvastatin administered as a single oral dose (Lescol, 20 mg) to a healthy volunteer revealed stereoselectivity, with the highest plasma concentrations being observed for the (-)-3S,5R isomer (Cmax 92.4 vs. 60.3 ng/ml, AUC(0-infinity) 133.3 vs. 97.4 ng h/ml, Cl/f 150.2 vs. 205.2 l h(-1) and Vd/f 4.4 vs. 6.0 l/kg).

Reproductive parameters and efficiency of inseminators in dairy farms in Portugal

This study was carried out to determine the reproductive efficiency indices of one of the largest dairy co-operatives of northern Portugal, using data from 1980 to 1998. Records were made available by the computerized National Recording System. Age at first calving was 32.0 +/- 6.0 months. Mean calving to first AI interval was 95.4 +/- 30.0 days, and calving to conception intervals decreased (p < 0.05) from 176.9 +/- 4.5 to 148.1 +/- 5.6 days from the first to the fourth/fifth parturitions, respectively. Calving intervals decreased (p < 0.05) from 418.1 +/- 3.4 to 392.5 +/- 7.0 days from the first to fourth/fifth parturitions, respectively. Mean non-return rates at 90 days for first inseminations was 71.7 +/- 6.5% and mean calving rates at first insemination was 51.4 +/- 8.1%. There were significant differences (p < 0.001) in the inseminators' efficiency, measured by both non-return and calving rates at first AI, with differences between the best and worst results of 13.3 and 16.1% for non-return and calving rates, respectively. The ranking of the inseminators did not coincide when their efficiency was measured by either non-return or calving rates. The mean number of inseminations per pregnancy (pregnant cows only) was 1.4 +/- 0.7 with significant (p < 0.001) differences among herds. The mean heat detection rate was 38.1 +/- 16.9%, with highly significant (p < 0.001) differences among farms (ranging from 14.2 to 60.8%). Negative (p < 0.001) correlations were found between heat detection rate and calving to first AI, calving to conception and calving intervals. The meaning of these indexes for assessment of reproductive efficiency in the studied system, is discussed.

Immunocytochemical localization of antigens recognized by asymptomatic microfilaremic patient's antisera in microfilariae of Wuchereria bancrofti

Ultrathin sections of microfilariae of Wuchereria bancrofti embedded in hydrophilic resin were incubated with sera from patients, using antisera from asymptomatic microfilaremic patients with different microfilarial densities [1-100 microfilariae (mf)/ml, 101-500 mf/ml, > 1,000 mf/ml]. All groups studied showed reactivity against relevant epitopes in all tissues of microfilariae of W. bancrofti, instead of being localized in a specific nematode region, although the number of colloidal per square micron was inversely proportional to the microfilaremia. Such results confirm data obtained by other authors and indicate a possible role for the humoral response in the mechanism for the destruction of circulating microfilariae.

First confirmed case of Neospora caninum-associated abortion outbreak in Portugal

In a dairy herd experiencing an abortion outbreak, 49% of the 119 cows were positive for Neospora caninum antibodies and the remaining 51% were seronegative. Using immunohistochemical analysis of foetal brain tissue, Neospora cysts and bradyzoite clusters were identified in two of the 15 aborted foetuses submitted for testing. Other agents that commonly cause abortions were not found. These results, coupled with neurological clinical symptoms in new-born calves, implicated N. caninum as the major cause of abortions in this dairy herd. This is the first report that associates N. caninum infection with bovine abortions in Portugal.

Chemical treatment and tissue selection: factors that influence the mechanical behaviour of porcine pericardium

Calcification and mechanical failure are the major causes of the loss of cardiac bioprostheses. The chemical treatments used to stabilize the tissue employed are considered to play a fundamental role in the development of these two phenomena, although the problem is multifactorial and the underlying causes are yet to be fully identified. Currently, there is an ongoing search for chemical treatments capable of reducing or eliminating the process of calcification while preserving the mechanoelastic characteristics of the tissue. One of the approaches to this effort is the elimination of the phospholipid component from the biological tissue employed in prosthesis construction. There is evidence that this component may be responsible for the precipitation of calcium salts. The present study compares two delipidating chemical treatments involving chloroform/methanol and sodium dodecyl sulfate (SDS) with the use of glutaraldehyde (GA) alone. For this purpose, porcine pericardial tissue was subjected to tensile strength testing employing a hydraulic simulator. A total of 234 samples were studied 90 treated with GA, 72 treated with chloroform/methanol and 72 treated with SDS. The mean breaking strength was significantly higher in the samples treated with GA (between 43.29 and 63.01 MPa) when compared with those of tissue treated with chloroform/methanol (29.92-42.30 MPa) or with SDS (13.49-19.06 MPa). In a second phase of the study, selection criteria based on morphological and mechanical factors were applied to the pericardial membranes employing a system of paired samples. The mathematical analysis of the findings in one fragment will aid in determining the mechanical behavior of its adjacent twin sample. In conclusion, the anticalcification chemical treatments tested in the experimental model conferred a lesser mechanical resistance than that obtained with GA. On the other hand, the utilization of paired samples was found to be useful in the prediction of the mechanical behavior of porcine pericardial tissue. Nevertheless, in order for our method of selection to be considered the most adequate approach, it will be necessary to validate these findings in dynamic studies involving a real, functional model.