Molecular test for COVID-19 diagnosis based on a colorimetric genomagnetic assay

The world is in a long pandemic period caused by the SARS-CoV-2 virus and massive diagnostic tests to assist efforts to control the spread of the disease and also to avoid new coronavirus variants are still needed. Herein, we propose a simple and accurate saliva-based colorimetric test for the diagnosis of COVID-19. Magnetic beads (MBs) modified with a sequence of single-strand DNA (ssDNA) complementary to the N gene of the SARS-CoV-2 RNA were developed and used for magnetic capture and separation from a complex saliva sample. A second biotinylated ssDNA sequence was applied, and the colorimetric detection was carried out by adding streptavidin-horseradish peroxidase conjugate, H₂O_2, and tetramethylbenzidine (TMB) as chromogenic substrate. The test does not require viral RNA isolation, transcription, or amplification steps and can be performed at room temperature. The molecular assay test can be run using 96-well microplates, allowing the diagnosis of a large number of samples in 90 min. A simple support for magnets was designed and constructed using a 3D printer that allows the magnetic separations directly in the 96-well microplate. The colorimetric test showed an excellent ability to discriminate between healthy individuals and patients infected with SARS-CoV-2, with 92% and 100% of clinical sensitivity and specificity, respectively. This performance was similar to that achieved using the gold standard RT-PCR technique. The proposed genomagnetic assay offers an opportunity to greatly increase population testing, contribute to controlling the spread of the virus, and improve health equity in testing for COVID-19.

The effect of denudation and injection timing in the reproductive outcomes of ICSI cycles: new insights into the risk of in vitro oocyte ageing

STUDY QUESTION

Does the time elapsed between oocyte pick-up (OPU) and denudation or injection affect the probability of achieving a live birth (LB) in ICSI cycles?

SUMMARY ANSWER

Prolonged oocyte culture before denudation (>4 h) was associated with an increase in clinical pregnancy (CP), LB and cumulative LB (CLB) rates when compared with earlier denudation timings.

WHAT IS KNOWN ALREADY

Oocyte maturation is a complex and dynamic process involving structural and biochemical modifications in the cell necessary to support fertilization and early embryo development. While meiotic competence is easily identifiable by the presence of an extruded first polar body, cytoplasmic maturation cannot be assessed microscopically. Culturing oocytes with their surrounding cumulus cells (CCs) prior to ICSI can enhance the completion of in vitro cytoplasmic maturation; conversely, prolonged culture may induce cell degeneration. The optimal culture intervals prior to oocyte denudation and/or injection have not yet been established and may prove relevant for the improvement of ICSI reproductive outcomes.

STUDY DESIGN, SIZE, DURATION

This is a single-centre retrospective cohort analysis of 1378 ICSI cycles performed between January 2005 and October 2018. Data were categorized according to: (i) the time interval between OPU and denudation (<3 h, 3-4 h and ≥4 h), (ii) the time interval between denudation and ICSI (<1.5 h, 1.5-2 h, ≥2 h) and (iii) the time interval between OPU and ICSI (<5 h, 5-6 h and ≥6 h). The effect of these timings on fertilization, CP, LB and CLB rates were compared. The culture intervals between different procedures were dependent exclusively on laboratory workload.

PARTICIPANTS/MATERIALS, SETTING, METHODS

ICSI cycles performed in women younger than 40 years old using autologous gametes with at least one metaphase II injected oocyte were included. The effect of oocyte culture duration prior to denudation and injection of the oocytes was compared using multivariable regression accounting for potential confounding variables.

MAIN RESULTS AND THE ROLE OF CHANCE

Fertilization and oocyte damage rate after ICSI was found to be independent of the time interval to denudation (<3 h, 3-4 h and ≥4 h) and/or injection (<5 h, 5-6 h and ≥6 h). Extending oocyte culture before denudation significantly improved CP (29.5%, 42.7% and 50.6%, respectively), LB (25.1%, 34.4% and 40.7%, respectively) and CLB rates (26.0%, 36.1% and 42.2%, respectively), particularly if the time interval was at least 4 h. Additionally, LB (31.7%, 35.8% and 27.4%, respectively) and CLB rates (34.2%, 36.6% and 27.7%, respectively) were also dependent on the time from OPU to injection.

LIMITATIONS, REASONS FOR CAUTION

This study is limited by its retrospective nature and potential unmeasured confounding cannot be excluded. Furthermore, the effect of even shorter or longer periods of culture before denudation and/or injection were not evaluated and should not be extrapolated from these results.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings propose new evidence of a previously unrecognized protective effect of the CCs-oocyte interactions in human ART, raising the question of a possible downstream effect in embryogenesis which significantly affects LB rates. Additionally, this is the first study to suggest a negative effect of further extending culture before ICSI on LB and CLB rates, thus potentially allowing for the narrowing of an optimal ICSI time interval. Simple strategies such as the establishment of more effective time frames to perform these procedures and adjusting laboratory practice may prove beneficial, ultimately improving ICSI reproductive outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

None.

TRIAL REGISTRATION NUMBER

N/A.

Four Years' Experience in the Diagnosis of Very Long-Chain Acyl-CoA Dehydrogenase Deficiency in Infants Detected in Three Spanish Newborn Screening Centers

Identification of very long-chain acyl-CoA dehydrogenase deficiency is possible in the expanded newborn screening (NBS) due to the increase in tetradecenoylcarnitine (C14:1) and in the C14:1/C2, C14:1/C16, C14:1/C12:1 ratios detected in dried blood spots. Nevertheless, different confirmatory tests must be performed to confirm the final diagnosis. We have revised the NBS results and the results of the confirmatory tests (plasma acylcarnitine profiles, molecular findings, and lymphocytes VLCAD activity) for 36 cases detected in three Spanish NBS centers during 4 years, correlating these with the clinical outcome and treatment. Our aim was to distinguish unambiguously true cases from disease carriers in order to obtain useful diagnostic information for clinicians that can be applied in the follow-up of neonates identified by NBS.Increases in C14:1 and of the different ratios, the presence of two pathogenic mutations, and deficient enzyme activity in lymphocytes (<12% of the intra-assay control) identified 12 true-positive cases. These cases were given nutritional therapy and all of them are asymptomatic, except one. Seventeen individuals were considered disease carriers based on the mild increase in plasma C14:1, in conjunction with the presence of only one mutation and/or intermediate residual activity (18-57%). In addition, seven cases were classified as false positives, with normal biochemical parameters and no mutations in the exonic region of ACADVL. All these carriers and the false positive cases remained asymptomatic. The combined evaluation of the acylcarnitine profiles, genetic results, and residual enzyme activities have proven useful to definitively classify individuals with suspected VLCAD deficiency into true-positive cases and carriers, and to decide which cases need treatment.

Methylmalonic aciduria cblB type: characterization of two novel mutations and mitochondrial dysfunction studies

Methylmalonic aciduria (MMA) cblB type is caused by mutations in the MMAB gene, which codes for the enzyme adenosine triphosphate (ATP): cobalamin adenosyltransferase (ATR). This study reports differences in the metabolic and disease outcomes of two pairs of siblings with MMA cblB type, respectively harbouring the novel changes p.His183Leu/p.Arg190dup (P1 and P2) and the previously described mutations p.Ile96Thr/p.Ser174fs (P3 and P4). Expression analysis showed p.His183Leu and p.Arg190dup to be destabilizing mutations. Both were associated with reduced ATR stability and a shorter half-life than wild-type ATR. Analysis of several parameters related to oxidative stress and mitochondrial function showed an increase in reactive oxygen species (ROS) content, a decrease in mitochondrial respiration and changes in mitochondria morphology and structure in patient-derived fibroblasts compared to control cells. The impairment in energy production and the presence of oxidative stress and fission of the mitochondrial reticulum suggested mitochondrial dysfunction in cblB patients' fibroblasts. The recovery of mitochondrial function should be a goal in efforts to improve the clinical outcome of MMA cblB type.

[(2R,3R)-3-(4-Nitrophenyl)aziridin-2-yl]methanol monohydrate

The title monohydrate, C₉H₁₀N₂O₃·H₂O, contains an aziridine ring including two contiguous stereocenters, both of which exhibit an R configuration. The methyl­hydroxy and nitro­phenyl groups are cis-disposed about the aziridine ring. The mean plane of the benzene ring is tilted to the aziridine ring by 66.65 (8)°. The nitro group is nearly coplanar with the benzene ring [dihedral angle = 2.5 (2)°]. In the crystal, the components are linked by N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds, generating supra­molecular layers parallel to (001).

Lack of in vivo embryotoxic and genotoxic activities of orally administered stem bark aqueous extract of Mangifera indica L. (Vimang)

Mango (Mangifera indica L.) stem bark aqueous extract (MSBE) is a new natural product with antioxidant, anti-inflammatory and immunomodulatory effects known by the brand name of its formulations as Vimang. Previously, the oral toxicity studies of the extract showed a low toxicity potential up to 2000 mg/kg. This work reports the results about teratogenic and genotoxicologic studies of MSBE. For embryotoxicity study, MSBE (20, 200, or 2000 mg/kg/day) was given to Sprague-Dawley rats by gavage on days 6-15 of gestation. For genotoxicity, MSBE was administered three times during 48 h to NMRI mice. Cyclophosphamide (50 mg/kg) was used as a positive control. No maternal or developmental toxicities were observed when the rats were killed on day 20th. The maternal body-weight gain was not affected. No dose-related effects were observed in implantations, fetal viability or external fetal development. Skeletal and visceral development was similar among fetuses from all groups. No genotoxicity was observed in bone marrow erythrocytes and liver cells after administration. MSBE appears to be neither embryotoxic nor genotoxic as measured by bone marrow cytogenetics in rodents.

Nuclear DNA content of Vitis vinifera cultivars and ploidy level analyses of somatic embryo-derived plants obtained from anther culture

Flow cytometry was employed to determine the ploidy level of Vitis vinifera L. somatic embryo-derived plants obtained from anther culture. Only one among the 41 analysed plants (2.4%) presented somaclonal variation (tetraploidy); the other plants were diploid. No significant differences (P<or=0.05) were detected between diploid and parental field plants. No haploid or aneuploid plants were observed. The nuclear DNA content of nine V. vinifera cultivars was also estimated using flow cytometry. A non-significant variation was found among the cultivars, with DNA content ranging from 1.17 pg/2C (cv. 'Tinta Barroca' and 'Viosinho') to 1.26 pg/2C (cv. 'Cabernet Sauvignon'). These results and previous studies on other Vitis species suggest that Vitis genome is stable with regard to nuclear DNA content.

Synthesis and in vitro studies of pyrone derivatives as scavengers of active oxygen species

The antioxidant properties of eleven alpha-pyrones and four gamma-pyrones were evaluated by means of three different tests: reduction of the stable free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion scavenging assay and lipid peroxidation assay. In the DPPH test, 6-aryl-5,6-dihydro-4-hydroxypyran-2-ones (3) and 4-hydroxypyran-2-one (5f) were the most active derivatives with IC50 values ranging from 36.7 to 394 mumol/l. Potent superoxide anion scavenging properties appeared in derivatives possessing phenol moieties. Thus phenolic pyrones 5e and 5f exhibited a noteworthy activity (IC50 = 0.180 and 0.488 mmol/l, respectively) when reference compound, ascorbic acid, demonstrated only 24% inhibition at a concentration of 1 mg/ml. In addition derivative 5f significantly inhibited the Fe2+/ADP/ascorbate-induced lipid peroxidation of rat liver microsomes with an IC50 value of 0.069 mmol/l. Due to its multiple mechanism of protective action, compound 5f may be useful for the treatment of oxidative tissue injury in human disease.

Synthesis of N-substituted 4,6-dioxo-imidazo[3,4-c] thiazoles and their analgesic activity in mice

A new series of N-substituted dioxo-imidazo[3,4-c]thiazoles have been prepared and evaluated for their analgesic activity. The structures of these new derivatives were confirmed by lR, 1H NMR and 13C NMR spectra, and by elemental analysis. When administered intraperitoneally to mice all derivatives were devoid of any toxic effect, even at the high dose of 800 mg kg(-1). In the phenylbenzoquinone-induced abdominal constriction test in mice, eight of the nine synthesized compounds exhibited significant antinociceptive properties with ED50 values (50% effective dose) ranging from 46.7 to 104.7 mg kg(-1) intraperitoneally. Further investigation demonstrated that analgesic activity of the most effective derivatives 5e and 5f partly involved opioidergic and/or noradrenergic pathways.

Thermally induced conformational changes in horseradish peroxidase

Detailed differential scanning calorimetry (DSC), steady-state tryptophan fluorescence and far-UV and visible CD studies, together with enzymatic assays, were carried out to monitor the thermal denaturation of horseradish peroxidase isoenzyme c (HRPc) at pH 3.0. The spectral parameters were complementary to the highly sensitive but integral method of DSC. Thus, changes in far-UV CD corresponded to changes in the overall secondary structure of the enzyme, while that in the Soret region, as well as changes in intrinsic tryptophan fluorescence emission, corresponded to changes in the tertiary structure of the enzyme. The results, supported by data about changes in enzymatic activity with temperature, show that thermally induced transitions for peroxidase are irreversible and strongly dependent upon the scan rate, suggesting that denaturation is under kinetic control. It is shown that the process of HRPc denaturation can be interpreted with sufficient accuracy in terms of the simple kinetic scheme N -->k D where k is a first-order kinetic constant that changes with temperature, as given by the Arrhenius equation; N is the native state, and D is the denatured state. On the basis of this model, the parameters of the Arrhenius equation were calculated.

Does literacy have an effect on stick construction tasks?

Since constructional apraxia is often concomitant with brain lesions, the study of constructional tasks in the non-brain-damaged population might be useful in helping to disentangle other causal factors. This paper explores the performance of illiterate individuals (N = 29) as compared to that of semiliterates (N = 21) and literates (N = 23) in order to see the effect of reading and writing abilities on constructional tasks. Each participant was asked to construct 4 figures based upon models having varying degrees of complexity. A global criterion of lack of fidelity and several analytic criteria (related to distortion, rotation, and disarticulation errors) were used to evaluate performance. Although illiterates generally made more errors than semiliterates and semiliterates more than literates, only some of these differences were statistically significant. Significant differences were found for lack of global fidelity and disarticulation errors when all 4 figures were considered together. Subtler data emerged with respect to single figures.

Coherence in short narratives written by Spanish-speaking children with reading disabilities

A novel analysis of coherence using a combination of three criteria (syntactic connexity, pragmatic complexity, and rhetorical well-roundedness) was applied to short narratives produced by a group of 60 Spanish-speaking children of different ages and grades with reading disabilities and compared to those produced by normal children. We posit a scale of 6 degrees of increasing coherence. This feature of children's writing, together with 2 others (viz. number of propositions, or "story points," recovered and number of words employed), was compared to features of children's reading by means of discriminant analysis in relation to age. We show that the combination of age, words read per minute, and degree of coherence achieved an optimal discrimination of the 2 groups.

Distinctive properties of the catalase B of Aspergillus nidulans

Aspergillus nidulans catalase B (CatB) was purified to homogeneity and characterized as a hydroperoxidase which resembles typical catalases in some physicochemical characteristics: (1) it has an apparent molecular weight of 360000 and is composed of four glycosylated subunits, (2) it has hydrophobic properties as revealed by extractability in ethanol/chloroform and binding to phenyl-Superose, and (3) it has an acidic isoelectric point at pH 3. 5. Also CatB exhibits some distinctive properties, e.g. it is not inhibited by the presence of 2% sodium dodecyl sulfate, 9 M urea or reducing agents. Furthermore, even though CatB does not exhibit any residual peroxidase activity, it is able to retain up to 38% of its initial catalase activity after incubation with the typical catalase inhibitor 3-amino-1,2,4-triazole.

Antioxidant properties of novel lipophilic ascorbic acid analogues

Structural modifications of ascorbic acid by the introduction of lipophilic moieties has led to derivatives with increased stability against thermal and oxidative degradation. Two series of new lipophilic ascorbic analogues were synthesized to obtain antioxidants devoid of autooxidant properties: 4-benzoyl-3-hydroxyfuran-2(5H)-ones (3a-j) and 4-acetyl-5-aryl-3,4-dihydrofuran-2(5H)ones (5a-f). These compounds were submitted to three different tests: reduction of the stable free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH); superoxide-anion scavenging assay; and lipid-peroxidation assay. Most compounds interacted with DPPH: at a concentration of 5 x 10(-3) M, the reducing activity of 4-benzoyl derivatives, 3c and 3h, was more than 50%; under the same conditions, the rate of inhibition for 4-acetylbutanolides, 5a and 5f, reached 60.6% and 87.3%, respectively; 93.3% inhibition was observed with ascorbic acid. In the superoxide-anion scavenging assay, at a concentration of 1 mg mL(-1), 4-benzoyl derivatives, 3g and 3i, exhibited a good activity, with IC50 (dose resulting in 50% inhibition) values of 1.45 and 1.35 x 10(-3) M, respectively. 4-Acetylbutanolide, 5f, significantly inhibited the Fe2+/ADP/ascorbate-induced lipid peroxidation of rat liver microsomes with an IC50 of 4.9 x 10(-4) M. This study demonstrates that enol functions in the structure of ascorbic acid analogues are not absolutely essential to bring about antioxidant effects.

Zinc-regulated biosynthesis of immunodominant antigens from Aspergillus spp

ASPND1 and ASPF2 are immunodominant antigens from Aspergillus nidulans and A. fumigatus, respectively, that are readily synthesized in infections in the human host, as demonstrated by their reactivity with more than 80% of sera from patients with aspergilloma or allergic bronchopulmonary aspergillosis. We demonstrate here that both antigens are exclusively produced under situations of low bioavailability of free Zn2+. Addition of micromolar concentrations of Zn2+ to the culture medium strongly stimulated Aspergillus growth but totally inhibited ASPND1 or ASPF2 production. This effect was specific, since other divalent metals had no effect. Removal of endogenous Zn2+ by a chelator also stimulated ASPND1 production, and the effect was specifically reversed by Zn2+. These results suggest a possible role of these antigens in the survival of the fungus in the lungs.

Antioxidant activity of some ascorbic and cinnamic acids derivatives

Some 4-benzoyl 3-hydroxy furan-2 (5H) ones (3a-d) and 2-amino 3-hydroxymethyl 4-aryl 4-oxo 2-butenoic acids (4a-h) have been synthesized. Compound 3c with an isobutyl substituent in the 5-position of the furan ring was the most effective (IC50 = 8.69 x 10(-4) M) in scavenging the superoxide anion. In vivo, 3c was also protective against reperfusion injury.

Cloning and disruption of the antigenic catalase gene of Aspergillus fumigatus

Aspergillus fumigatus possesses two catalases (described as fast and slow on the basis of their electrophoretic mobility). The slow catalase has been recognized as a diagnostic antigen for aspergillosis in immunocompetent patients. The antigenic catalase has been purified. The enzyme is a tetrameric protein composed of 90-kDa subunits. The corresponding cat1 gene was cloned, and sequencing data show that the cat1 gene codes for a 728-amino-acid polypeptide. A recombinant protein expressed in Pichia pastoris is enzymatically active and has biochemical and antigenic properties that are similar to those of the wild-type catalase. Molecular experiments reveal that CAT1 contains a signal peptide and a propeptide of 15 and 12 amino acid residues, respectively. cat1-disrupted mutants that were unable to produce the slow catalase were as sensitive to H2O2 and polymorphonuclear cells as the wild-type strain. In addition, there was no difference in pathogenicity between the cat1 mutant and its parental cat1+ strain in a murine model of aspergillosis.

Protein involvement in thermally induced structural transitions of pig erythrocyte ghosts

Thermal transitions in pig erythrocyte ghosts were studied by differential scanning calorimetry and thermal gel analysis (TGA). Heating of the suspension of pig erythrocyte ghosts induced at least six thermodynamically irreversible transitions. Each of these transitions is believed to be due to a localized structural transition induced by thermal stress. Using TGA and covalent attachment of the anionic transport inhibitor regions in the thermograms corresponding to the heat sorption of some proteins of the pig erythrocyte ghosts were identified.

Characterization of the Aspergillus nidulans aspnd1 gene demonstrates that the ASPND1 antigen, which it encodes, and several Aspergillus fumigatus immunodominant antigens belong to the same family

For the first time, an immunodominant Aspergillus nidulans antigen (ASPND1) consistently reactive with serum samples from aspergilloma patients has been purified and characterized, and its coding gene (aspnd1) has been cloned and sequenced. ASPND1 is a glycoprotein with four N-glycosidically-bound sugar chains (around 2.1 kDa each) which are not necessary for reactivity with immune human sera. The polypeptide part is synthesized as a 277-amino-acid precursor of 30.6 kDa that after cleavage of a putative signal peptide of 16 amino acids, affords a mature protein of 261 amino acids with a molecular mass of 29 kDa and a pI of 4.24 (as deduced from the sequence). The ASPND1 protein is 53.1% identical to the AspfII allergen from Aspergillus fumigatus and 48% identical to an unpublished Candida albicans antigen. All of the cysteine residues and most of the glycosylation sites are perfectly conserved in the three proteins, suggesting a similar but yet unknown function. Analysis of the primary structure of the ASPND1 coding gene (aspnd1) has allowed the establishment of a clear relationship between several previously reported A. fumigatus and A. nidulans immunodominant antigens.

Immunoblotting patterns in the serodiagnosis of aspergilloma: antibody response to the 90kDa Aspergillus fumigatus antigen

At present there are no accepted criteria to assess the usefulness of Western blot assays for the serodiagnosis of aspergilloma. An Aspergillus fumigatus cytosolic fraction complex (CFC) composed of four proteins (p90, p60, p40, and p37) has been identified. The usefulness of Western blotting with CFC antigens for the serodiagnosis of aspergilloma was evaluated in 25 patients with well-established diagnoses and in 94 controls. The most consistently reactive antigen was p90 (92% of patients with aspergilloma), followed by p40 (76%) and the entire CFC taken together (76%). With these data, interpretive criteria for positive and negative immunoblots were established, with p90 indicated as a helpful marker of aspergilloma.

Effect on free radical processes of some ascorbic acid analogues

Ascorbic acid, present in plasma from humans at concentrations of 50 to 200 mumol/l, has multiple antioxidant properties. Structural modification of this vitamin by the introduction of lipophilic moieties has allowed to the development of ascorbate esters and ethers active as free radical quenchers. Thus, a new series of ascorbic acid analogues possessing one or two aromatic rings was prepared in an attempt to synthesize potent antioxidants with lipophilic properties. Substituted 3-hydroxy furan-2 (5H)-ones and in some cases, dihydrofuro[3,4-b]pyrones were prepared. The synthesized compounds were evaluated for their antioxidant activity in vitro. So, 4-(4-methoxybenzoyl)-3-hydroxy-5-phenylfuran-2(5H)-one 3e (IC50 = 3.06 x 10(-4) M) was found to be the most effective in scavenging the superoxide anion, whereas 4-benzoyl-3-hydroxy-5-(3,4-dimethoxyphenyl)furan- 2(5H)-one 3d (IC50 = 1.38 x 10(-4) M) was the most active in inhibiting, lipid peroxidation.

An immunodominant 90-kilodalton Aspergillus fumigatus antigen is the subunit of a catalase

We have identified, purified, and characterized structurally and functionally a 90-kDa immunodominant antigen associated with the water-soluble fraction of Aspergillus fumigatus. This antigen is recognized by 90.3% of serum samples from patients with aspergilloma and should be considered either by itself or better in combination with other purified antigens as a candidate for developing a standardized immunoassay for the detection of aspergilloma. p90 is a glycoprotein containing at least two two N-linked sugar chains of 2 and 5 kDa, respectively, which are not necessary for its reactivity with aspergilloma serum samples. Using specific anti-p90 rabbit serum, we have demonstrated that under native conditions, p90 exists in oligomeric form and has associated catalase activity. This activity is resistant to extreme temperatures (> 60 degrees C), reducing agents (40 mM dithiothreitol), high concentrations of denaturing agents such as 8 M urea and 8% sodium dodecyl sulfate, and treatments with ethanol-chloroform-water (5:3:10 [vol/vol]) mixtures.

Aspergillus fumigatus antigens

Cytosolic fractions of mycelial extracts from Aspergillus nidulans, A. flavus, and three different isolates of A. fumigatus, grown to stationary phase in Czapek-Dox-AOAC medium, were tested by immunoblotting for the presence of antigens reactive to 80 serum samples from aspergilloma patients. Fifty control serum samples were used to determine the specificity of the reactions. In the A. fumigatus cytosolic fraction a group of four main antigenic bands (p90, p60, p40 and p37) was consistently recognized (in total or partial form) by 90% of the serum samples from the aspergilloma patients. This group of antigens was designated as the 'cytosolic fraction complex' (CFC). As confirmed by two-dimensional electrophoresis followed by immunoblotting with aspergilloma serum samples, each of the four antigenic bands is formed of several isoforms of acidic glycopeptides with slightly different pls. All the isoforms are at least N-glycosylated, as demonstrated by endoglycosidase H removal of a considerable amount of sugar residues. The relationship of these antigens with certain other A. fumigatus antigens previously reported in the literature, and their potential use in the immunodiagnosis of aspergilloma, are discussed.

Pituitary down-regulation in IVF cycles: is it necessary to use strict criteria?

PURPOSE

In a retrospective study we have reviewed the data of 570 consecutive IVF cycles in which a GnRH agonist (GnRHa) was started in the early follicular phase (long protocol). Cycles were divided in groups according to estradiol levels before HMG administration: A, < 20 pg/ml; B, 20 to 50 pg/ml; C, 51 to 100 pg/ml. Our objective was to determine if the degree of pituitary suppression had any effect on the ovarian response to stimulation by exogenous gonadotropins, and/or on the IVF outcome.

RESULTS

There were no significant differences in cycle cancellation rates, no. of days of stimulation and ampoules of HMG, serum estradiol after HMG, no. of oocytes retrieved and fertilization rates between groups. Pregnancy rates (19.4%, 21% and 31.8%/cycle, and 24.1%, 27.5% and 37.8% / embryo transfer, respectively) and live-birth rates (16.2%, 16.1% and 25.0%/cycle, 20.1%, 21.2% and 29.7%/embryo transfer, respectively) were also not significantly different.

CONCLUSIONS

The degree of pituitary suppression had no effects on either the ovarian response to gonadotropins (including HMG requirements) or the overall IVF results.

[The effect of the woman's age, the rate of cleavage and embryo quality on obtaining a pregnancy by in-vitro fertilization]

Multiple factors influence the probability of obtaining a pregnancy through in vitro fertilization (IVF) and embryo transfer (ET). This retrospective study was designed to assess their importance in order to improve prognostic ability and treatment success. 341 consecutive embryo transfer cycles using the same ovarian stimulation protocol were considered and divided in two main groups: 92 cycles in which a clinical pregnancy was achieved and 249 cycles without success. All the embryo transfers were performed in patients from the in vitro fertilization program of the Human Reproductive Unit, Santa Maria Hospital, Lisbon, between January 1991 and December 1993. No significant differences were found between the two groups studied concerning the IVF indications, ovarian response to the stimulation, sperm quality, oocyte maturation and mean number of oocytes retrieved per patient. The women's age was higher in the group which did not achieve a pregnancy, when compared with the pregnant group (p < 0.001), showing a decline of success after the age of 35. Overall oocyte fertilization rate was 88.2% in cycles with pregnancy and 83.5% in cycles without pregnancy (p < 0.02). In the pregnant patients, there was a significantly higher rate of embryo transfers in which all the embryos received had reached at least the four-cell stage at 42-43 hr postinsemination, compared with the non pregnant patients (82% versus 63%, p < 0.001). All the 92 pregnancies originated from transfers of at least one embryo that had undergone two or more mitotic divisions.(ABSTRACT TRUNCATED AT 250 WORDS)

Variability of Aspergillus nidulans antigens with media and time and temperature of growth

The influence of culture medium and time and temperature of growth on the appearance of Aspergillus nidulans antigens was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by silver staining or Western blot (immunoblot), of the proteins present in total cellular extracts or culture supernatants. Samples in the exponential, deceleration, and stationary growth phases were selected by biochemical, morphological, and ultrastructural criteria. Protein and antigen patterns (detected with rabbit antibodies) from total extracts were very similar in all cases, and the major differences observed seemed to depend on the age of the cultures. Culture supernatant patterns were highly dependent on the type of medium (complex or defined) and the age of the culture. Temperature did not significantly influence these results. The reproducible reactivity of selected human sera from aspergilloma-affected individuals was strictly associated with the use of defined media, especially Czapek Dox-AOAC, in both total extracts and culture supernatants. Extended growth times were necessary in the case of metabolic antigens (those obtained from culture supernatants). Screening of a battery of 10 selected human serum samples from patients with aspergilloma or invasive aspergillosis demonstrated that two of the antigens (96 to 98 and 45 kDa) from stationary-phase culture supernatants in Czapek Dox-AOAC medium were consistently reactive. When considered together as one unit, both antigens reacted with more than 50% of the sera, and at least one or the other of the antigens reacted with more than 90% of the sera. Less consistent results were obtained for two somatic antigens (from total cell extracts) of 45 to 50 and 20 to 22 kDa.

Fractured zona oocytes in in-vitro fertilization cycles stimulated with gonadotrophin-releasing hormone analogue and human menopausal gonadotrophin

In order to assess the possible influence of gonadotrophin-releasing hormone analogue and human menopausal gonadotrophin on the occurrence of fractured zona oocytes (FZOs) in in-vitro fertilization (IVF) treatment cycles, we analysed 267 consecutive cycles in 199 patients. In 87 cycles, at least one fractured zona oocyte was recovered, and in 180 cycles only intact zona oocytes (IZOs) were recovered. FZOs represented 5.8% of all oocytes retrieved and 14.8% when only cycles with FZOs were considered. Serum oestradiol concentrations were significantly higher at day -3 and day -2 (P < 0.02) in cycles yielding at least one fractured zona oocyte compared to IZO cycles (day 0 = retrieval day), and there was a higher incidence of G terminal pattern of oestradiol curve (P < 0.01) in cycles with FZOs. The mean numbers of all oocytes retrieved and of mature oocytes were significantly higher in FZO than in IZO cycles (P < 0.001). The fertilization rate of mature oocytes was significantly reduced (P < 0.05) in cycles with one or more oocytes with fractured zonae. There was no significant difference in the number of embryos transferred, pregnancy and abortion rates in both groups. We conclude that although the occurrence of fractured zona oocytes is a frequent event, it does not affect the overall results of our IVF programme. Zona pellucida fragility may be the result of over-maturation of some oocytes.

Immunogenic potential of Aspergillus nidulans subcellular fractions and their polypeptide components

Cell-free extracts of the ascomycetous fungus Aspergillus nidulans were separated into three subcellular fractions: cell walls, total membranes and cytosol, and two different immunization protocols were used to raise antibodies against them in 12 New Zealand rabbits. The immune response was followed over time by dot and Western blot analyses to determine the immunogenic potential of each individual fraction and their polypeptide components. The IgG fractions, purified from pools of the best sera, were used to analyze in detail the antigenic composition of A. nidulans mycelium. The fast immunization protocol provided a much earlier response and higher sera titres. Cytosols and membranes were more immunogenic than cell walls and, in most cases, a positive correlation was shown between the titre of each serum and the number of detected antigens. The polypeptides of A. nidulans included six major immunodominant antigens of the molecular weights ranging between 13 and 200 kDa.

Analysis of Aspergillus nidulans conidial antigens and their prevalence in other Aspergillus species

Aspergillus nidulans is an ascomycetous fungus that reproduces asexually by forming multicellular conidiophores and uninucleate spores called conidia. These elements constitute the main vehicle for the transmission of this and other pathogenic Aspergillus species and are the starting point of the different forms of aspergillosis. In order to use A. nidulans as a potential source of useful antigens for the immunodiagnosis of these diseases, we have examined the total protein composition of conidial extracts of this fungus by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis in gels of different percent T. Injection of SDS-extracted conidial proteins into rabbits allowed us to raise a battery of polyclonal antibodies which have defined some important immunogenic polypeptides. Several of these immunogens were both present in mycelial extracts and recognized by antimycelium antibodies. Four of them, designated cdA, cdB, cdC, and cdE, were also found in conidial extracts of other pathogenic Aspergillus species. Only cdE was undetectable in cell extracts of the nonrelated species Fusarium culmorum and Phycomyces blakesleeanus.

Fluid-phase endocytosis in yeasts other than Saccharomyces cerevisiae

A FITC-dextran internalization assay with Saccharomyces cerevisiae as positive control was used to determine whether fluid-phase endocytosis is a general characteristic of yeasts. Schizosaccharomyces pombe, Pichia polymorpha, Kluyveromyces phaseolosporus, Yarrowia lipolytica and Candida albicans were clearly positive, whereas results obtained with Debaryomyces marama were inconclusive. In all cases internalized FITC-dextran was found to be localized in the vacuoles and the process was always time- and temperature-dependent. Lower eucaryotes, particularly yeasts, appear to have the ability to incorporate substances from the extracellular medium through fluid-phase endocytosis.

Group G Streptococci: susceptibility patterns and the effect of the inoculum size and growth phase on the bactericidal activity of penicillin

Twenty-seven independent group G streptococcal isolates were studied by in vitro susceptibility testing against 22 different antimicrobial agents. Penicillin with a MIC90 of 0.03 micrograms/ml and ampicillin with a MIC90 of less than or equal to 0.015 micrograms/ml remain the agents of first choice for treatment of group G streptococcal infections. Tolerance was not demonstrated using the macrobroth dilution method in four media, Todd-Hewitt, Mueller-Hinton, Mueller-Hinton (cation-supplemented), and Tryptose Phosphate broths. Multiple regression analyses of time-kill curves of group G streptococci showed that the rate of cell death with penicillin at 0.04 micrograms/ml (five times greater than each organism's MIC) for both logarithmic- and stationary-phase cells with low-inocula were the same, but were five to six times greater in rate of death compared to the high-inocula cultures. Increasing the concentration to 1 microgram/ml of penicillin (125 times greater than each organism's MIC) did not significantly affect the rate of cell death for low-inocula cultures of either phase. Therefore, the size of the inoculum was found to be more significant than the phase of bacterial growth. These findings may explain the therapeutic discrepancy of relapses or prolonged group G streptococcal infections despite the organism being susceptible to the given antibiotic.