Relationship between Physicochemical and Cooking Quality Parameters with Estimated Glycaemic Index of Rice Varieties

Rice is a significant staple food in the basic diet of the global population that is considered to have a high glycaemic index. The study of the physical and chemical parameters in rice that are related to the starch digestion process, which allows us to quickly predict the glycaemic index of varieties, is a major challenge, particularly in the classification and selection process. In this context, and with the goal of establishing a relationship between physicochemical properties and starch digestibility rates, thus shedding light on the connections between quality indicators and their glycaemic impact, we evaluated various commercial rice types based on their basic chemical composition, physicochemical properties, cooking parameters, and the correlations with digestibility rates. The resistant starch, the gelatinization temperature and the retrogradation (setback) emerge as potent predictors of rice starch digestibility and estimated glycaemic index, exhibiting robust correlations of r = -0.90, r = -0.90, and r = -0.70 (p ≤ 0.05), respectively. Among the rice types, Long B and Basmati stand out with the lowest estimated glycaemic index values (68.44 and 68.10), elevated levels of resistant starch, gelatinization temperature, and setback values. Furthermore, the Long B showcases the highest amylose, while the Basmati with intermediate, revealing intriguingly strong grain integrity during cooking, setting it apart from other rice varieties.

Fluid extraction from the left-right organizer uncovers mechanical properties needed for symmetry breaking

Humans and other vertebrates define body axis left-right asymmetry in the early stages of embryo development. The mechanism behind left-right establishment is not fully understood. Symmetry breaking occurs in a dedicated organ called the left-right organizer (LRO) and involves motile cilia generating fluid-flow therein. However, it has been a matter of debate whether the process of symmetry breaking relies on a chemosensory or a mechanosensory mechanism (Shinohara et al., 2012). Novel tailored manipulations for LRO fluid extraction in living zebrafish embryos allowed us to pinpoint a physiological developmental period for breaking left-right symmetry during development. The shortest critical time-window was narrowed to one hour and characterized by a mild counterclockwise flow. The experimental challenge consisted in emptying the LRO of its fluid, abrogating simultaneously flow force and chemical determinants. Our findings revealed an unprecedented recovery capacity of the embryo to re-fil and re-circulate new LRO fluid. The embryos that later developed laterality problems were found to be those that had lower anterior angular velocity and thus less anterior-posterior heterogeneity. Next, aiming to test the presence of any secreted determinant, we replaced the extracted LRO fluid by a physiological buffer. Despite some transitory flow homogenization, laterality defects were absent unless viscosity was altered, demonstrating that symmetry breaking does not depend on the nature of the fluid content but is rather sensitive to fluid mechanics. Altogether, we conclude that the zebrafish LRO is more sensitive to fluid dynamics for symmetry breaking.

Evidence for an association of prenatal exposure to particulate matter with clinical severity of Autism Spectrum Disorder

Early-life exposure to air pollutants, including ozone (O₃), particulate matter (PM_2.5 or PM₁₀, depending on diameter of particles), nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) has been suggested to contribute to the etiology of Autism Spectrum Disorder (ASD). In this study, we used air quality monitoring data to examine whether mothers of children with ASD were exposed to high levels of air pollutants during critical periods of pregnancy, and if higher exposure levels may lead to a higher clinical severity in their offspring. We used public data from the Portuguese Environment Agency to estimate exposure to these pollutants during the first, second and third trimesters of pregnancy, full pregnancy and first year of life of the child, for 217 subjects with ASD born between 2003 and 2016. These subjects were stratified in two subgroups according to clinical severity, as defined by the Autism Diagnostic Observational Schedule (ADOS). For all time periods, the average levels of PM_2.5, PM₁₀ and NO₂ to which the subjects were exposed were within the admissible levels defined by the European Union. However, a fraction of these subjects showed exposure to levels of PM_2.5 and PM₁₀ above the admissible threshold. A higher clinical severity was associated with higher exposure to PM_2.5 (p = 0.001), NO₂ (p = 0.011) and PM₁₀ (p = 0.041) during the first trimester of pregnancy, when compared with milder clinical severity. After logistic regression, associations with higher clinical severity were identified for PM_2.5 exposure during the first trimester (p = 0.002; OR = 1.14, 95%CI: 1.05-1.23) and full pregnancy (p = 0.04; OR = 1.07, 95%CI: 1.00-1.15) and for PM₁₀ (p = 0.02; OR = 1.07, 95%CI: 1.01-1.14) exposure during the third trimester. Exposure to PM is known to elicit neuropathological mechanisms associated with ASD, including neuroinflammation, mitochondrial disruptions, oxidative stress and epigenetic changes. These results offer new insights on the impact of early-life exposure to PM in ASD clinical severity.

Zebrafish Motile Cilia as a Model for Primary Ciliary Dyskinesia

Zebrafish is a vertebrate teleost widely used in many areas of research. As embryos, they develop quickly and provide unique opportunities for research studies owing to their transparency for at least 48 h post fertilization. Zebrafish have many ciliated organs that include primary cilia as well as motile cilia. Using zebrafish as an animal model helps to better understand human diseases such as Primary Ciliary Dyskinesia (PCD), an autosomal recessive disorder that affects cilia motility, currently associated with more than 50 genes. The aim of this study was to validate zebrafish motile cilia, both in mono and multiciliated cells, as organelles for PCD research. For this purpose, we obtained systematic high-resolution data in both the olfactory pit (OP) and the left-right organizer (LRO), a superficial organ and a deep organ embedded in the tail of the embryo, respectively. For the analysis of their axonemal ciliary structure, we used conventional transmission electron microscopy (TEM) and electron tomography (ET). We characterised the wild-type OP cilia and showed, for the first time in zebrafish, the presence of motile cilia (9 + 2) in the periphery of the pit and the presence of immotile cilia (still 9 + 2), with absent outer dynein arms, in the centre of the pit. In addition, we reported that a central pair of microtubules in the LRO motile cilia is common in zebrafish, contrary to mouse embryos, but it is not observed in all LRO cilia from the same embryo. We further showed that the outer dynein arms of the microtubular doublet of both the OP and LRO cilia are structurally similar in dimensions to the human respiratory cilia at the resolution of TEM and ET. We conclude that zebrafish is a good model organism for PCD research but investigators need to be aware of the specific physical differences to correctly interpret their results.

Primary ciliary dyskinesia due to CCNO mutations-A genotype-phenotype correlation contribution

Primary ciliary dyskinesia (PCD) is genetically and clinically heterogeneous. CCNO mutations are associated with chronic destructive lung disease and were first described in 2014. Early reports suggest that CCNO is mutated more frequently than expected, however, these are considered rare. We report on three eleven-year-old children with PCD due to CCNO mutations. All children presented early-onset respiratory symptoms, no cardiac or situs anomalies and moderate to severe clinical courses. Patients 1 and 3 were admitted to a neonatal intensive care unit due to respiratory distress. Patients 1 and 2 had atelectasis and lobar collapse, for which lobectomy was performed for patient 1. Patient 3 also presented otitis media with effusion with conductive hearing loss, requiring tympanostomy tube insertion twice. Diagnosis of PCD for all three required repeated nasal brushings, delaying diagnostic confirmation. Microscopy analysis revealed severely decreased numbers of cilia, but normal ultrastructure and uncoordinated beat pattern in the residual cilia. Surprisingly, the prevalence of pathogenic CCNO variants in our centre is higher than expected (three out of sixteen patients). Pathogenic variants in PCD-causing genes lead to specific ultrastructural defects, and there is a suggestion for genotype-phenotype association. However, there are little longitudinal data evaluating the impact of specific defects on disease progression, but a recent study showed a worse lung disease and poorer nutritional status. Concluding, this report underlies the importance of patient-oriented diagnosis and management in highly experienced PCD centres.

Pkd2 Affects Cilia Length and Impacts LR Flow Dynamics and Dand5

The left-right (LR) field recognizes the importance of the mechanism involving the calcium permeable channel Polycystin-2. However, whether the early LR symmetry breaking mechanism is exclusively via Polycystin-2 has not been tested. For that purpose, we need to be able to isolate the effects of decreasing the levels of Pkd2 protein from any eventual effects on flow dynamics. Here we demonstrate that curly-up (cup) homozygous mutants have abnormal flow dynamics. In addition, we performed one cell stage Pkd2 knockdowns and LR organizer specific Pkd2 knockdowns and observed that both techniques resulted in shorter cilia length and abnormal flow dynamics. We conclude that Pkd2 reduction leads to LR defects that cannot be assigned exclusively to its putative role in mediating mechanosensation because indirectly, by modifying cell shape or decreasing cilia length, Pkd2 deficit affects LR flow dynamics.

CiliarMove: new software for evaluating ciliary beat frequency helps find novel mutations by a Portuguese multidisciplinary team on primary ciliary dyskinesia

Evaluation of ciliary beat frequency (CBF) performed by high-speed videomicroscopy analysis (HVMA) is one of the techniques required for the correct diagnosis of primary ciliary dyskinesia (PCD). Currently, due to lack of open-source software, this technique is widely performed by visually counting the ciliary beatings per a given time-window. Our aim was to generate open-source, fast and intuitive software for evaluating CBF, validated in Portuguese PCD patients and healthy volunteers. Nasal brushings collected from 17 adult healthy volunteers and 34 PCD-referred subjects were recorded using HVMA. Evaluation of CBF was compared by two different methodologies: the new semi-automated computer software CiliarMove and the manual observation method using slow-motion movies. Clinical history, nasal nitric oxide and transmission electron microscopy were performed for diagnosis of PCD in the patient group. Genetic analysis was performed in a subset (n=8) of suspected PCD patients. The correlation coefficient between the two methods was R2=0.9895. The interval of CBF values obtained from the healthy control group (n=17) was 6.18-9.17 Hz at 25°C. In the PCD-excluded group (n=16), CBF ranged from 6.84 to 10.93 Hz and in the PCD group (n=18), CBF ranged from 0 to 14.30 Hz. We offer an automated open-source programme named CiliarMove, validated by the manual observation method in a healthy volunteer control group, a PCD-excluded group and a PCD-confirmed group. In our hands, comparisons between CBF intervals alone could discern between healthy and PCD groups in 78% of the cases.

Imbalanced mitochondrial function provokes heterotaxy via aberrant ciliogenesis

About 1% of all newborns are affected by congenital heart disease (CHD). Recent findings identify aberrantly functioning cilia as a possible source for CHD. Faulty cilia also prevent the development of proper left-right asymmetry and cause heterotaxy, the incorrect placement of visceral organs. Intriguingly, signaling cascades such as mTor that influence mitochondrial biogenesis also affect ciliogenesis, and can cause heterotaxy-like phenotypes in zebrafish. Here, we identify levels of mitochondrial function as a determinant for ciliogenesis and a cause for heterotaxy. We detected reduced mitochondrial DNA content in biopsies of heterotaxy patients. Manipulation of mitochondrial function revealed a reciprocal influence on ciliogenesis and affected cilia-dependent processes in zebrafish, human fibroblasts and Tetrahymena thermophila. Exome analysis of heterotaxy patients revealed an increased burden of rare damaging variants in mitochondria-associated genes as compared to 1000 Genome controls. Knockdown of such candidate genes caused cilia elongation and ciliopathy-like phenotypes in zebrafish, which could not be rescued by RNA encoding damaging rare variants identified in heterotaxy patients. Our findings suggest that ciliogenesis is coupled to the abundance and function of mitochondria. Our data further reveal disturbed mitochondrial function as an underlying cause for heterotaxy-linked CHD and provide a mechanism for unexplained phenotypes of mitochondrial disease.

Characterization of gastric cells infection by diverse Helicobacter pylori strains through Fourier-transform infrared spectroscopy

The infection of Helicobacter pylori, covering 50% of the world-population, leads to diverse gastric diseases as ulcers and cancer along the life-time of the human host. To promote the discovery of biomarkers of bacterial infection, in the present work, Fourier-transform infrared spectra were acquired from adenocarcinoma gastric cells, incubated with H. pylori strains presenting different genotypes concerning the virulent factors cytotoxin associated gene A and vacuolating cytotoxin A. Defined absorbance ratios were evaluated by diverse methods of statistical inference, according to the fulfillment of the tests assumptions. It was possible to define from the gastric cells, diverse absorbance ratios enabling to discriminate: i) The infection; ii) the bacteria genotype; and iii) the gastric disease of the patients from which the bacteria were isolated. These biomarkers could fasten the knowledge of the complex infection process while promoting a platform for a new diagnostic method, rapid but also specific and sensitive towards the diagnosis of both infection and bacterial virulence.

Dataset of Near-infrared spectroscopy measurement for amylose determination using PLS algorithms

In the dataset presented in this article, 168 rice samples comprising sixteen rice varieties (including Indica and Japonica sub species) from a Portuguese Rice Breeding Program obtained from three different sites along four seasons, and 11 standard rice varieties from International Rice Research Institute were characterised. The amylose concentration was evaluated based on iodine method, and the near infrared (NIR) spectra were determined. To assess the advantage of Near infrared spectroscopy, different rice varieties and specific algorithms based on Matlab software such as Standard Normal Variate (SNV), Multiple Scatter Calibration (MSC) and Savitzky-Golay filter were used for NIR spectra pre-processing.

Notch/Her12 signalling modulates, motile/immotile cilia ratio downstream of Foxj1a in zebrafish left-right organizer

Foxj1a is necessary and sufficient to specify motile cilia. Using transcriptional studies and slow-scan two-photon live imaging capable of identifying the number of motile and immotile cilia, we now established that the final number of motile cilia depends on Notch signalling (NS). We found that despite all left-right organizer (LRO) cells express foxj1a and the ciliary axonemes of these cells have dynein arms, some cilia remain immotile. We identified that this decision is taken early in development in the Kupffer's Vesicle (KV) precursors the readout being her12 transcription. We demonstrate that overexpression of either her12 or Notch intracellular domain (NICD) increases the number of immotile cilia at the expense of motile cilia, and leads to an accumulation of immotile cilia at the anterior half of the KV. This disrupts the normal fluid flow intensity and pattern, with consequent impact on dand5 expression pattern and left-right (L-R) axis establishment.

Dynamics of cilia length in left-right development

Reduction in the length of motile cilia in the zebrafish left-right organizer (LRO), also known as Kupffer's vesicle, has a large impact on left-right development. Here we demonstrate through genetic overexpression in zebrafish embryos and mathematical modelling that the impact of increased motile cilia length in embryonic LRO fluid flow is milder than that of short cilia. Through Arl13b overexpression, which increases cilia length without impacting cilia beat frequency, we show that the increase in cilium length is associated with a decrease in beat amplitude, resulting in similar flow strengths for Arl13b overexpression and wild-type (WT) embryos, which were not predicted by current theory. Longer cilia exhibit pronounced helical beat patterns and, consequently, lower beat amplitudes relative to WT, a result of an elastohydrodynamic shape transition. For long helical cilia, fluid dynamics modelling predicts a mild (approx. 12%) reduction in the torque exerted on the fluid relative to the WT, resulting in a proportional reduction in flow generation. This mild reduction is corroborated by experiments, providing a mechanism for the mild impact on organ situs.

The zebrafish Kupffer's vesicle as a model system for the molecular mechanisms by which the lack of Polycystin-2 leads to stimulation of CFTR

In autosomal dominant polycystic kidney disease (ADPKD), cyst inflation and continuous enlargement are associated with marked transepithelial ion and fluid secretion into the cyst lumen via cystic fibrosis transmembrane conductance regulator (CFTR). Indeed, the inhibition or degradation of CFTR prevents the fluid accumulation within cysts. The in vivo mechanisms by which the lack of Polycystin-2 leads to CFTR stimulation are an outstanding challenge in ADPKD research and may bring important biomarkers for the disease. However, hampering their study, the available ADPKD in vitro cellular models lack the three-dimensional architecture of renal cysts and the ADPKD mouse models offer limited access for live-imaging experiments in embryonic kidneys. Here, we tested the zebrafish Kupffer's vesicle (KV) as an alternative model-organ. KV is a fluid-filled vesicular organ, lined by epithelial cells that express both CFTR and Polycystin-2 endogenously, being each of them easily knocked-down. Our data on the intracellular distribution of Polycystin-2 support its involvement in the KV fluid-flow induced Ca²⁺-signalling. Mirroring kidney cysts, the KV lumen inflation is dependent on CFTR activity and, as we clearly show, the knockdown of Polycystin-2 results in larger KV lumens through overstimulation of CFTR. In conclusion, we propose the zebrafish KV as a model organ to study the renal cyst inflation. Favouring its use, KV volume can be easily determined by in vivo imaging offering a live readout for screening compounds and genes that may prevent cyst enlargement through CFTR inhibition.

Summary: Here, we tested the zebrafish Kupffer's vesicle (KV) as a model organ to study, through in vivo imaging of KV volume, the stimulation of cystic fibrosis transmembrane conductance regulator (CFTR) in autosomal dominant polycystic kidney disease ADPKD.

Left-right organizer flow dynamics: how much cilia activity reliably yields laterality?

Internal organs are asymmetrically positioned inside the body. Embryonic motile cilia play an essential role in this process by generating a directional fluid flow inside the vertebrate left-right organizer. Detailed characterization of how fluid flow dynamics modulates laterality is lacking. We used zebrafish genetics to experimentally generate a range of flow dynamics. By following the development of each embryo, we show that fluid flow in the left-right organizer is asymmetric and provides a good predictor of organ laterality. This was tested in mosaic organizers composed of motile and immotile cilia generated by dnah7 knockdowns. In parallel, we used simulations of fluid dynamics to analyze our experimental data. These revealed that fluid flow generated by 30 or more cilia predicts 90% situs solitus, similar to experimental observations. We conclude that cilia number, dorsal anterior motile cilia clustering, and left flow are critical to situs solitus via robust asymmetric charon expression.

Attachment, spreading and short-term proliferation of human osteoblastic cells cultured on chitosan films with different degrees of acetylation

Chitosan (Ch) is being actively investigated as a non-protein template for the growth of an increasing number of anchorage-dependent cells, including chondrocytes and bone cells. In the present work, Ch films with degrees of N-acetylation (DAs) in the range of 4 to 49% were evaluated with respect to the attachment, spreading and short-term proliferation of osteoblasts, using human osteoblastic MG-63 cells. The films were characterized in terms of surface morphology and surface charge by atomic force microscopy and streaming potential measurements, respectively. Cell attachment was assessed after 3 and 24 h of cell culture. After 24 h of incubation, cell attachment was found to be dependent on the DA, lower DAs favouring cell adhesion. With time, cell spreading and cytoskeleton organization were only attained for DAs <or= 13%. Regarding cell proliferation, cells grown on films with the lowest DA (4%) revealed a higher specific growth rate as compared to those grown on films with higher DAs. Films with a DA of 49% failed to sustain cell proliferation. In addition, a longer lag-phase was observed on Ch, as compared to TCPS, in accordance to an observed delay of cell spreading. The present findings revealed that differences in the DA as small as 9% may be critical in terms of the osteoblast response to two-dimensional Ch-based matrices.

Epidemiology of candidemia in oncology patients: a 6-year survey in a Portuguese central hospital

This study presents data on the incidence of candidemia in a Portuguese oncology hospital during a 6-year period. The species distribution and their antifungal susceptibility, as well as the clinical outcomes associated with candidemia were evaluated. A total of 119 episodes were reported, with the majority occurring among patients older than 56 years. The most common underlying medical conditions were solid tumors (64.5%) and hematological disease (28.2%). The most frequent species found was Candida albicans (48.7%), followed by C. parapsilosis (20.2%), C. tropicalis (8.4%), C. krusei (6.7%) and C. glabrata (5.0%), but Saccharomyces cerevisiae and Rhodotorula mucilaginosa were also isolated. Candida albicans was more frequently associated with solid tumors of the gastrointestinal and genitourinary tracts and breast (P=0.005), while non-C. albicans Candida species were most frequently recovered from hematological patients (P=0.007). The mortality rate associated with candidemia was 31.9% (P=0.016). All C. albicans and C. parapsilosis isolates were susceptible to fluconazole, voriconazole and itraconazole. Resistance to caspofungin was only observed in C. albicans and in the R. mucilaginosa isolates. Posaconazole was active against all C. parapsilosis isolates tested but resistant strains were found among C. albicans (4.9%), C. tropicalis (12.5%), C. krusei (25%) and C. glabrata (50%). This study provides useful information regarding the local epidemiology of candidemia in cancer patients.

Osteoblast adhesion and morphology on TiO2 depends on the competitive preadsorption of albumin and fibronectin

This study aims at assessing the influence of the competitive preadsorption of human serum albumin (HSA) and human plasma fibronectin (FN) from binary solutions and 10% plasma on MC3T3-E1 osteoblast adhesion and morphology on two types of TiO2 substrates. One was commercially pure titanium with a titanium oxide layer formed in an H2O2 solution and the other TiO2 sputtered on Si (Sousa et al., Langmuir 2004; 20:9745-9754.). The strategy applied in the present investigation was to compare osteoblast adhesion to surfaces preadsorbed with HSA, FN, HSA/FN = 1, HSA/FN = 200, and 10% plasma. The adsorption of proteins was evaluated measuring the amount and the effectiveness of binding with radiolabeled proteins, 125 I-FN and 125 I-HSA. Our results indicated that MC3T3-E1 osteoblast adhesion correlates well with the amounts of FN and HSA adsorbed on TiO2 surfaces. Also, we found that fewer osteoblasts adhered to both substrates preadsorbed with HSA, HSA/FN = 200, and 10% plasma, after 4 and 24 h, than to the surfaces preadsorbed with FN and HSA/FN = 1. For the latter, FN was able to compensate the inhibitory effect of HSA on osteoblast adhesion. Therefore, the presence of lower amounts of coadsorbed albumin may improve presentation of FN in a more integrin-recognized conformation, suggesting that some degree of molecular packing prevents loss of integrin-binding activity. FN reversibility does not seem to be dependent on the HSA/FN adsorption mass ratio in solution, suggesting that FN competitively adsorbs to TiO2 in a favorable conformation and does not suffers subsequent conformational changes allowing exchange with other FN molecules in solution.

Alginate/chitosan nanoparticles are effective for oral insulin delivery

PURPOSE

To evaluate the pharmacological activity of insulin-loaded alginate/chitosan nanoparticles following oral dosage in diabetic rats.

METHODS

Nanoparticles were prepared by ionotropic pre-gelation of an alginate core followed by chitosan polyelectrolyte complexation. In vivo activity was evaluated by measuring the decrease in blood glucose concentrations in streptozotocin induced, diabetic rats after oral administration and flourescein (FITC)-labelled insulin tracked by confocal microscopy.

RESULTS

Nanoparticles were negatively charged and had a mean size of 750 nm, suitable for uptake within the gastrointestinal tract due to their nanosize range and mucoadhesive properties. The insulin association efficiency was over 70% and insulin was released in a pH-dependent manner under simulated gastrointestinal conditions. Orally delivered nanoparticles lowered basal serum glucose levels by more than 40% with 50 and 100 IU/kg doses sustaining hypoglycemia for over 18 h. Pharmacological availability was 6.8 and 3.4% for the 50 and 100 IU/kg doses respectively, a significant increase over 1.6%, determined for oral insulin alone in solution and over other related studies at the same dose levels. Confocal microscopic examinations of FITC-labelled insulin nanoparticles showed clear adhesion to rat intestinal epithelium, and internalization of insulin within the intestinal mucosa.

CONCLUSION

The results indicate that the encapsulation of insulin into mucoadhesive nanoparticles was a key factor in the improvement of its oral absorption and oral bioactivity.

Three-dimensional culture of human osteoblastic cells in chitosan sponges: the effect of the degree of acetylation

In this investigation, the effect of the degree of acetylation (DA) of chitosan on the behavior of human osteoblastic MG-63 cells cultured in three-dimensional chitosan matrices was assessed. Chitosan sponges with DAs in the range of 4 to 49% were prepared and characterized in terms of microstructure, porosity, and pore size. Collagen sponges were used as 3D control. Cell proliferation was determined using the MTT assay while the retention of the osteoblastic phenotype was monitored by assaying alkaline phosphatase activity. Cell morphology, cytoskeletal organization, and viability were assessed using different microscopy techniques. Chitosan sponges showed a similar microstructure regardless the DA, except for the highest DA used, where a more heterogeneous pore distribution was observed. In terms of cell proliferation, alkaline phosphatase activity and cell viability, cells cultured in chitosan scaffolds performed as well as in the 3D control regardless the DA, except for the highest DA used, where an inhibitory effect on cell proliferation was found. However, while in sponges with DAs < or = 13% cells attached and spread displaying long cell filopodia and numerous cell-to-cell contacts, in sponges with higher DAs cells tended to remain spherical and grow into spheroid-like cellular aggregates. In the present study, the DA played a key role in determining the affinity of osteoblastic cells towards the substrates, possibly by influencing the nature of the initial adsorbed protein layer.

Rat bone marrow stromal cell osteogenic differentiation and fibronectin adsorption on chitosan membranes: The effect of the degree of acetylation

Cell adhesion, migration, and proliferation of a few anchorage-dependent cells cultured on chitosan (Ch) matrices are influenced by the degree of N-acetylation (DA) of Ch. In the present work, we examined the influence of the DA on the attachment, spreading, proliferation, and osteogenic differentiation of rat bone marrow stromal cells (rBMSCs). Ch membranes were characterized in terms of surface morphology, roughness, and wettability, and in terms of adsorption of an adhesive protein, fibronectin (Fn). Chs with DAs in the range of 4 to 49% were used. Among the Ch samples, the DA of 4% led to the highest Fn surface concentration, both from single protein solution and from diluted serum. Furthermore, the levels of Fn adsorbed from serum found for this DA were threefold higher than for the tissue culture polystyrene control, indicating that in the presence of competitive proteins Ch is more specific toward Fn adsorption than tissue culture polystyrene. rBMSCs cultured on Ch carrying a DA of 4% were able to spread, proliferate, and differentiate, reaching a higher level of osteogenic differentiation than on the control, despite the lower cell attachment observed for all Ch samples. Because the Ch sample with a DA of 4% showed the highest Fn adsorption from serum, we suggest that cell adhesion, spreading, and osteogenic differentiation of rBMSCs on Ch may be mediated by the adsorbed layer of Fn.

Use of recombinant cyprosin in the manufacture of ewe's milk cheese

A recombinant cyprosin from the cardoon (Cynara cardunculus L.) was assayed and compared with calf rennet in batches of ewes' milk cheese by determining different chemical, biochemical, and microbiological parameters over 4 months of ripening. There were no differences between the two types of coagulants in most chemical parameters, a(w), and pH. Proteolysis was more marked and rapid in cheese containing recombinant cyprosin as coagulant, the soluble nitrogen content of which was significantly higher (p < 0.01) than that of the cheese obtained with animal rennet; at the end of ripening the nonprotein nitrogen of cheese produced with recombinant cyprosin was slightly higher (p > 0.05) as compared with that in cheeses obtained with animal rennet. Microbial counts in the milk used for making cheese were high in most of the groups analyzed. Despite slight differences in counts, the main microbial groups analyzed were similar in cheese produced with both types of coagulants throughout ripening.

Organized microtubule arrays in gamma-tubulin-depleted Drosophila spermatocytes

To assess the role of gamma-tubulin in spindle assembly in vivo, we have followed meiosis progression by immunofluorescence and time-lapse video microscopy in gammaTub23C(PI) mutant spermatocytes. We have found that centrosomes associate with large numbers of astral microtubules even though gamma-tubulin is severely depleted; bipolar meiotic spindles are never assembled; and later in meiosis, the microtubules get organized into a conical structure that is never observed in wild-type cells. Several lines of evidence suggest that these cones may be related to wild-type central spindles. First, they are assembled midway through meiosis and elongate during anaphase. Second, they are constricted during late meiosis, giving rise to a pointed end similar to those that form in each half of the wild-type spindle midzone. Third, Klp3A and Polo, two markers of the wild-type central spindle are also found around the pointed end of the mutant cones. Finally, ectopic cytokinesis furrows are often formed at the distal end of the cone. Our results suggest that microtubule polymerization or stabilization from the centrosome may be possible in a gamma-tubulin-independent manner in Drosophila spermatocytes. However, gamma-tubulin seems to be essential for spindle assembly in these cells. Finally, our results show that at least part of the central spindle and constriction-ring assembly machinery can operate on microtubule bundles that are not organized as bipolar spindles.

Mast, a conserved microtubule-associated protein required for bipolar mitotic spindle organization

Through mutational analysis in Drosopjila we have identified the gene multiple asters (mast), which encodes a new 165 kDa protein. mast mutant neuroblasts are highly polyploid and show severe mitotic abnormalities including the formation of mono- and multi-polar spindles organized by an irregular number of microtubule-organizing centres of abnormal size and shape. The mast gene product is evolutionarily conserved since homologues were identified from yeast to man, revealing a novel protein family. Antibodies against Mast and analysis of tissue culture cells expressing an enhanced green fluorescent protein-Mast fusion protein show that during mitosis, this protein localizes to centrosomes, the mitotic spindle, centromeres and spindle midzone. Microtubule-binding assays indicate that Mast is a microtubule-associated protein displaying strong affinity for polymerized microtubules. The defects observed in the mutant alleles and the intracellular localization of the protein suggest that Mast plays an essential role in centrosome separation and organization of the bipolar mitotic spindle.

In vivo localisation of the mitotic POLO kinase shows a highly dynamic association with the mitotic apparatus during early embryogenesis in Drosophila

The gene polo encodes a highly conserved serine/threonine protein kinase that has been implicated in several functions during cell division. Polo-like kinases are important positive regulators of cell cycle progression and have also been implicated in the exit from mitosis through the activation of the anaphase-promoting complex. Several data indicate that Plks are required for centrosome function, bipolar spindle organisation and cytokinesis. The intracellular localisation of Plks reflects their multiple roles in cell division, however, in vivo studies that describe the distribution of this protein during different stages of mitosis have never been performed. In the present work, we report the in vivo distribution of a GFP-POLO fusion protein expressed in stable transformants and analysed during the early embryonic development of Drosophila melanogaster. The GFP-POLO protein can be detected in unfertilised oocytes associated with the centromeric region of chromosomes of the polar body and followed until the formation of mitotic domains in later development. Detailed analysis of the dynamic localisation of GFP-POLO during syncytial mitotic cycles shows the timing of localisation to the centrosomes, centromeres and midbody. The results also indicate that GFP-POLO is present in astral microtubules early in mitosis, accumulates around the nuclear envelope until nuclear envelop breakdown and at metaphase associates to spindle microtubules. These in vivo studies show a highly dynamic association of POLO with multiple compartments of the mitotic apparatus. Furthermore, the wide distribution of the GFP-POLO protein to all compartments of the mitotic apparatus provides a valuable tool for future studies on cell cycle during development.

Gamma-tubulin is required for the structure and function of the microtubule organizing centre in Drosophila neuroblasts

We report that in Drosophila, gamma-tubulin is required for the structure as well as the function of microtubule organizing centres (MTOCs). This conclusion is based on the identification and phenotypic characterization of a mutant allele of the gamma-tubulin gene located at region 23C of the polytene chromosome map. This mutation, which we have called gamma-tub23CPl, is caused by the insertion of a P-element within the 5' untranslated leader of the gamma-tubulin transcript. Northern and Western analysis show that gamma-tub23CPl is either a null or a very severe hypomorph as no gamma-tubulin mRNA or protein can be detected in mutant individuals. Visualization of DNA, MTOCs and microtubules by confocal laser scanning microscopy of cells from individuals homozygous for gamma-tub23CPl reveals a series of phenotypic abnormalities. Some of these are similar to those observed after disruption of gamma-tubulin function in other organisms, including mitotic arrest and a dramatic decrease in the number of microtubules, but, in addition, we have observed that mutation in this gene also results in highly abnormal MTOCs which show a variety of shapes and sizes which we never observed in wild type cells. These results show that gamma-tubulin is required for both structural and functional roles in the MTOCs.

[Meningioma of the olfactory groove and breast neoplasms: report of 2 cases]

Two cases of olfactory groove meningiomas are presented in patients with breast cancer. Predominance of breast cancer and meningiomas in the age decades of the forties and the fifties, presence of steroid hormones receptors in both and prevalence of meningiomas in women are referred as significant correlations. Examination of the breast of women with meningiomas is recommended. Tomographic images are sometimes atypical, and a surgical intervention may be necessary.

[Intrasellar syndrome. Analysis of 506 cases of transsphenoidal surgery]

The author has performed 506 transsphenoidal surgeries but has analyzed in this study only 404 cases. There were 396 hypophyseal tumors, 4 intrasellar cysts and 4 empty sellas. Based in the symptoms presented by the patients he describes an "intrasellar syndrome", characterized by headache, visual disorders and hormonal abnormalities. He calls attention for intrasellar tumors with normal sella, as seen by x-ray. The diagnosis of these tumors were made only by endocrinological studies. At last he shows the advantages of transsphenoidal surgery in this pathology and the excellent results obtained. The mortality of his cases was only 0.2%.

[Intracranial saccular aneurysms: critical analysis of 456 surgical cases]

From January to December 1983 the author has operated on 456 intracranial aneurysms with microsurgical techniques. Most of them (74.8%) arose from the internal carotid and from the anterior communicating artery. Subarachnoid hemorrhage was the first occurrence in 92% of the patients. The favored technique was occlusion of the neck of the aneurysm with clip. The best surgical results were achieved when the patients were physical and mentally well and were operated on after a week following subarachnoid hemorrhage. The over all mortality was 6.2%.

[Treatment of cerebral fungus by ventriculoatrial shunt. Report of 5 cases]

The causes and pathology of the cerebral fungi are analyzed. Five patients with this lesion were submitted to ventriculoatrial shunt. All were cured. According to the authors this is the best treatment for cerebral fungus, at present.

[Caudal vertebro-medullary dysrhaphia. Intra-sacral forms]

The mean theories of the sacral spinal dysraphisms are reviewed and 4 cases of "meningeal intrasacral diverticulum" are reported. The authors prefer this term to the more common "intrasacral occult meningocele". The proeminent symptom in their cases was late vesical incontinence, which disappeared after surgery. In the pertinent literature 24 similar cases were described till now.

[Surgical treatment of hemifacial spasm. Considerations on 11 cases]

São feitas algumas considerações sobre a etiologia e tratamento do espasmo hemifacial, e apresentados os resultados cirúrgicos em 11 casos. Houve remissão completa em 9, e parcial em dois casos. Observou-se paresia facial permanente em 3 pacientes.

Aneurismas da artéria comunicante anterior: considerações sobre 14 casos operados

Após algumas considerações sobre a freqüência e o quadro clínico dos aneurismas da artéria comunicante anterior, é relatada a experiência do autor, constante de 14 casos operados: nove pacientes se recuperaram totalmente, um sobreviveu com incapacidade parcial e quatro faleceram. O tratamento cirúrgico, apesar de todos os percalços, é ainda a melhor terapêutica, quando possível. Para a indicação cirúrgica quanto às condições do paciente, foi seguida a classificação de Boterell e col. modificada por Hunt e Hess.