Ectopic ossification in the scar tissue of rats with myocardial infarction

We describe the occurrence of bone-like formations in the left ventricular wall of infarcted rats treated or not with bone marrow cells injected systemically or locally into the myocardium. The incidence of ectopic calcification in hearts has been reported in rare cases in children with infarcts without previous coronary artery disease. Recently, ventricular calcification has been correlated with unselected bone marrow cell transplantation into infarcted rat hearts. Echocardiographic analysis of large infarction in rats frequently reveals the presence of echogenic structures in the left ventricular wall, sometimes projecting to the lumen of the chamber. The histological examination of these echogenic structures exhibited bone, cartilage, and marrow-like formations extending from the collagen-rich matrix of the ventricle wall. Microanalytical techniques verified the presence of hydroxyapatite in the mineral phase. Ossification was found in 25 out of 30 hearts evaluated 90 days postinfarct, being observed in 14 out of 17 animals submitted to cell therapy and in 11 out of 13 infarcted rats not submitted to cell therapy. Our study indicates that chondro-osteogenic differentiation can take place in the pathological rat heart independent of animal treatment with marrow cells.

Ectopic ossification in the scar tissue of rats with myocardial infarction

We describe the occurrence of bone-like formations in the left ventricular wall of infarcted rats treated or not with bone marrow cells injected systemically or locally into the myocardium. The incidence of ectopic calcification in hearts has been reported in rare cases in children with infarcts without previous coronary artery disease. Recently, ventricular calcification has been correlated with unselected bone marrow cell transplantation into infarcted rat hearts. Echocardiographic analysis of large infarction in rats frequently reveals the presence of echogenic structures in the left ventricular wall, sometimes projecting to the lumen of the chamber. The histological examination of these echogenic structures exhibited bone, cartilage, and marrow-like formations extending from the collagen-rich matrix of the ventricle wall. Microanalytical techniques verified the presence of hydroxyapatite in the mineral phase. Ossification was found in 25 out of 30 hearts evaluated 90 days postinfarct, being observed in 14 out of 17 animals submitted to cell therapy and in 11 out of 13 infarcted rats not submitted to cell therapy. Our study indicates that chondro-osteogenic differentiation can take place in the pathological rat heart independent of animal treatment with marrow cells.

Histomorphometric Analysis of Tissue Responses to Bioactive Glass Implants in Critical Defects in Rat Calvaria

The aim of this study was to evaluate the osteogenic behavior of two chemically similar bioactive glass products (Biogranand Perioglas) implanted in critical bone defects in rat calvaria. Thirty-six transfixed bone defects of 8 mm diameter were made surgically in adult male Wistar rats. The animals were distributed equally into three groups: Biogran (GI), Perioglas (GII) and without implant material (control; GIII). The morphology and composition of both bioactive glasses were analyzed by scanning electron microscopy and energy-dispersive spectrometry. Tissue specimens were analyzed at the biological time points of 15, 30 and 60 days by optical microscopy and morphometry, demonstrating biocompatibility for the tested materials with moderate chronic inflammation involving their particles. Bone neoformation resulted only as a reparative reaction to an intentionally produced defect and was limited to the defect's edges. No statistically significant differences among the groups were observed. At the scar interstice, abundant deposits of collagenous fibers enveloping the particles were noted. The present results indicated that the bioactive glasses, under the experimental conditions analyzed, did not show osteogenic behavior.

Effect of in vivo administration of epidermal growth factor on prostaglandin production and NOS activity in term rat placentae. Possible participation of placental EGF receptors

Many authors hypothesize that the epidermal growth factor (EGF) is involved in the onset of labor. Previous reports from our laboratory showed that intrauterine administration of EGF delays the beginning of labor. The aims of this study were: 1) to analyze the effect of intrauterine administration of 500 ng EGF on placental prostaglandins and nitric oxide, and 2) to characterize the expression of EGF receptors (EGF-R) in pregnant rat placentae. Saline solution (sham group) and 500 ng EGF (EGF-treated group) were administered via intrauterine injection on day 21 of gestation, and both groups of animals were sacrificed on day 22 (sham rats delivered on day 22). Results showed that EGF treatment: 1) inhibited the production of prostaglandin E (p<0.001) and F(2alpha) (p<0.01), 2) increased the synthesis of nitric oxide (p<0.001), and 3) reduced the expression of cyclooxygenase-II, the enzyme responsible for PG synthesis. Placentae were found to express EGF-R and its activated form, and the expressions of both forms were higher at mid and term pregnancy. Hence, EGF is a very interesting molecule for studying the regulation of placental prostaglandin and nitric oxide production related to the parturition process.

Habits of magnetosome crystals in coccoid magnetotactic bacteria

High-resolution transmission electron microscopy and electron holography were used to study the habits of exceptionally large magnetite crystals in coccoid magnetotactic bacteria. In addition to the crystal habits, the crystallographic positioning of successive crystals in the magnetosome chain appears to be under strict biological control.

Multicellular life cycle of magnetotactic prokaryotes

Most multicellular organisms, prokaryotes as well as animals, plants, and algae have a unicellular stage in their life cycle. Here, we describe an uncultured prokaryotic magnetotactic multicellular organism that reproduces by binary fission. It is multicellular in all the stages of its life cycle, and during most of the life cycle the cells organize into a hollow sphere formed by a functionally coordinated and polarized single-cell layer that grows by increasing the cell size. Subsequently, all the cells divide synchronously; the organism becomes elliptical, and separates into two equal spheres with a torsional movement in the equatorial plane. Unicellular bacteria similar to the cells that compose these organisms have not been found. Molecular biology analysis showed that all the organisms studied belong to a single genetic population phylogenetically related to many-celled magnetotactic prokaryotes in the delta sub-group of the proteobacteria. This appears to be the first report of a multicellular prokaryotic organism that proliferates by dividing into two equal multicellular organisms each similar to the parent one.

Intracellular inclusions of uncultured magnetotactic bacteria

Magnetotactic bacteria produce magnetic crystals in organelles called magnetosomes. The bacterial cells may also have phosphorus-containing granules, sulfur globules, or polyhydroxyalkanoate inclusions. In the present study, the ultrastructure and elemental composition of intracellular inclusions from uncultured magnetotactic bacteria collected in a marine environment are described. Magnetosomes contained mainly defect-free, single magnetite crystals with prismatic morphologies. Two types of phosphorus-containing granules were found in magnetotactic cocci. The most common consisted of phosphorus-rich granules containing P, O, and Mg; and sometimes also C, Na, Al, K, Ca, Mn, Fe, Zn, and small amounts of S and Cl were also found. In phosphorus-sulfur-iron granules, P, O, S, Na, Mg, Ca, Fe, and frequently Cl, K, and Zn, were detected. Most cells had two phosphorus-rich granules, which were very similar in elemental composition. In rod-shaped bacteria, these granules were positioned at a specific location in the cell, suggesting a high level of intracellular organization. Polyhydroxyalkanoate granules and sulfur globules were less commonly seen in the cells and had no fixed number or specific location. The presence and composition of these intracellular structures provide clues regarding the physiology of the bacteria that harbor them and the characteristics of the microenvironments where they thrive.

[Locally advanced and recurrent pelvic colorectal carcinoma: results of aggressive surgical treatment]

Pelvic exenteration has been described as a formidable procedure in cases of advanced or recurrent pelvic cancers for a variety of primary tumors, including colorectal, gynaecologic and urologic. We report our 14-year experience in a community hospital with 37 cases who underwent pelvic exenteration for recurrent (n = 15) or locally advanced (n = 22) colorectal cancers. At a median follow-up of 36 months, the median survival was 24 and 36 months, respectively, and the 5-year actuarial survival was 18% and 44%.

[Does incidence of sentinel lymph node metastasis increase after diagnostic manipulation in women with breast cancer?]

503 patients were retrospectively evaluated to assess whether a previous needle or core biopsy, or surgical surgical excision of the primary tumor are associated with passive dislodgment of tumor cells in the sentinel lymph node, as reported in recent publications. We could not identify any increased incidence of sentinel lymph node micrometastases or isolated tumor cells after diagnostic manipulation of the primary tumor.

[Towards the standardization of sentinel lymph node analysis in women with breast cancer]

Sentinel lymph node biopsy allows enhanced pathology through serial sections and immunohistochemical analysis of the retrieved node, with detection of micrometastases and isolated tumor cells not otherwise recognized. We present our experience with a simple, effective, pathology protocol requiring six couples of sections at three different sentinel lymph node levels. Additional micrometastases or ITC were diagnosed in 51/416 patients (14.6%).

[Predictive variables of lymphatic metastasis in breast carcinoma with a diameter below 2 cm]

The axillary lymph node status of patients with newly diagnosed breast cancer remains the most important prognostic information available at the moment. However, only a minority of patients presents with such node metastases at diagnoses. We reviewed our database and studied 500 consecutive patients with early breast cancer, and found that age inferior to 50 years, high grade, diameter superior to 1 cm, elevated Ki-67, and expression of oncogene p-53 are all factors associated with lymph node metastases.

[Hormone-dependence and C-ERBB2: relationship between estrogen receptor expression, estrogen-regulated proteins, and C-ERBB2 in breast carcinoma]

We reviewed 1491 consecutive cases of operated breast cancer between 1999-2004, and found that hormone-dependence, particularly if evaluated with functional markers of the estrogen receptor (estrogen regulated proteins, ERP), is inversely proportional to antigen neu expression. Our data confirms that ERP can give additional information on the probability of response to hormonal therapy.

[Experience in prevention of risks caused by manual movement of patients in a health institution]

In its hospitals, the local Reggio Emilia Division of the National Health Service has introduced beds and stretchers with up-and-down movement systems, electrical lifters for patients, and highly mobile trained more than one thousand workers in the correct execution of maneuvers for moving patients manually platforms and litters for transferring patients from stretcher to bed. The Division has also. The risk evaluation models available in the literature have proved to be inadequate for instituting a program of improving service or for adequately supporting the doctor in charge. To overcome these limitations, a standard of risk evaluation called SpoSo ("Spostamenti Sollevamenti"--"Moving and Lifting") has been experimentally adopted.

Hematological changes in rats chronically exposed to oral aluminum

This study was aimed to investigate the effects of the long-term oral exposure to aluminum sulfate on hematological parameters in rats. For this purpose, 24 adult female Wistar rats were divided in three groups with 8 animals each (control, citrate, and citrate plus aluminum groups). Rats from control and citrate groups had free access to tap water and to a sodium citrate solution (35 mM), respectively. Rats from citrate plus aluminum group received, as unique source of liquid, an aluminum sulfate solution (30 mM) diluted in the above-mentioned sodium citrate solution, ad libitum. After the treatment period (18 months), aluminum-exposed rats showed a significant decrease in the number of red blood cells, blood hemoglobin concentration and hematocrit when compared to rats from the control group. Serum iron levels were also significantly lower in citrate plus aluminum group, whereas total iron binding capacity did not change after citrate plus aluminum exposure. Erythrocyte thiobarbituric acid-reactive substances (TBARS) and nonprotein thiols (NPSH) levels, erythrocyte osmotic fragility and hepatic delta-aminolevulinic acid dehydratase (delta-ALA-D) activity did not change after treatment with citrate plus aluminum. Conversely, aluminum exposure increased delta-ALA-D activity in bone marrow. The present results indicate that long-term oral exposure to low doses of aluminum sulfate promotes alterations on erythrocyte parameters in rats, probably as a consequence of alterations in the iron status. In addition, although the details of the underlying mechanism remain unclear, our study reports, for the first time, a stimulatory effect of chronic aluminum exposure on bone marrow delta-ALA-D activity.

Methylmercury increases S100B content in rat cerebrospinal fluid

S100B, a calcium binding protein physiologically produced and released by astrocytes, has been used as a peripheral marker of brain damage. Here, we investigated the effects of subcutaneous injections of methylmercury chloride (MeHg-5mg/kg), an environmental neurotoxicant, on S100B protein content in cerebrospinal fluid (CSF) of adult rats. In addition, the performance of animals in an open field (number of squares crossing and rearings) was also analyzed in order to obtain a possible link between alteration in S100B protein content in CSF and parameters related to neurological injury. MeHg treatment increased serum mercury and S100B protein levels in the CSF. A decrease in the numbers of crossings and rearings was observed in MeHg-treated animals when compared to control group, which suggests a possible neurological injury. The present data show, for the first time, increased S100B levels in CSF after exposure to a neurotoxic metal. Authors discuss the possibility of astrocytic involvement in MeHg-induced neurotoxicity.

Effects of surface undulations of biphasic calcium phosphate tablets on human osteoblast behavior

In this work, the in vitro behavior of human osteoblast cells on the undulated surfaces of biphasic calcium phosphate tablets was investigated. The tablets were produced by uniaxial pressing with convex cylindrical undulations occupying only half of the surface area; the other half was flat. Chemical and physical characterization was performed by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). XRD and FTIR analyses revealed the presence of hydroxyapatite (HA) and alpha-tricalcium phosphate (alpha-TCP) in a well-defined ratio. Moreover, microtopography, evaluated by SEM and AFM, was similar on the flat region and on that with undulations. However, surface undulations induced different cellular arrangements, confirming the influence of the macrotopography on the cells orientation.

Cell organization and ultrastructure of a magnetotactic multicellular organism

Magnetotactic multicellular aggregates and many-celled magnetotactic prokaryotes have been described as spherical organisms composed of several Gram-negative bacteria capable to align themselves along magnetic fields and swim as a unit. Here we describe a similar organism collected in a large hypersaline lagoon in Brazil. Ultrathin sections and freeze fracture replicas showed that the cells are arranged side by side and face both the external environment and an internal acellular compartment in the center of the organism. This compartment contains a belt of filaments linking the cells, and numerous membrane vesicles. The shape of the cells approaches a pyramid, with the apex pointing to the internal compartment, and the basis facing the external environment. The contact region of two cells is flat and represents the pyramid faces, while the contacts of three or more cells contain cell projections and represent the edges. Freeze-fracture replicas showed a high concentration of intramembrane particles on the edges and also in the region of the outer membrane that faces the external environment. Dark field optical microscopy showed that the whole organism performs a coordinated movement with either straight or helicoidal trajectories. We conclude that the organisms described in this work are, in fact, highly organized prokaryotic multicellular organisms.

Biosynthesis and catabolism of prostaglandin F2alpha (PGF2alpha) are controlled by progesterone in the rat uterus during pregnancy

Myometrial quiescence is a key factor in all species to accomplish a successful gestation. PGs play a crucial role in mediating parturition events, and their synthesis and metabolism are regulated by cyclooxygenases (COXs) and NAD(+)-dependent 15-hydroxy-PG dehydrogenase (PGDH), respectively. Progesterone (P(4)) is the hormone responsible for maintaining uterine smooth muscle quiescence during pregnancy. In this work, we have studied the effect of P(4) on the activity of COXs and PGDH, the uterine enzymes involved in the biosynthesis and metabolism of prostanoids in the rat. We found that during pregnancy PGF(2alpha) production and also protein levels of COX-1 and COX-2 were decreased. The exogenous administration of P(4) significantly inhibited the uterine production of PGF(2alpha) and also the protein level of COX-2. PGF(2alpha), metabolism was assessed by PGDH activity, which resulted high during pregnancy and increased as a result of P(4) administration. These results indicate that PGs levels were negatively modulated by P(4), which could be exerting its effect by increasing PGs metabolism through stimulation on PGDH activity and an inhibition on COX and that is a major mechanism for maintain uterine quiescence in pregnancy.

Magnetosome chain arrangement and stability in magnetotactic cocci

We have studied the disposition of chains of magnetosomes inside magnetotactic cocci with light and electron microscopy. Light microscopy of isolated cocci indicated that the chains of magnetosomes are disposed on opposite sides of the cell. Electron spectroscopic imaging of whole unprocessed bacteria, showed the magnetosome chains in the cells. Freeze-etching of the cell surface allowed the observation of the close association of the chain with the cell surface. During the replication process of the freeze-etching, the magnetosome chains remained attached to the replicas, which indicates that chains were very close to the cell surface before freezing. We provide evidence that the large area of the contact faces between magnetosomes in a chain may provide an extra mechanical stability that helps keep the magnetosomes in chains even after isolation from the bacteria. Comparison with pointed magnetosomes from different cocci present in the same samples showed that the maintenance of linear chains is more difficult to be achieved because of the geometry of the crystals.

Maternal Milk as Methylmercury Source for Suckling Mice: Neurotoxic Effects Involved with the Cerebellar Glutamatergic System

Methylmercury (MeHg) is a highly neurotoxic compound and several studies have reported intoxication signs in children whose mothers were exposed to this environmental toxicant. Although it is well established that the in utero exposure to MeHg causes neurological deficits in animals and humans, there is no evidence of the exclusive contribution of lactational exposure to MeHg as a possible cause of neurotoxicity in the offspring. In this study, we investigated the exclusive contribution of MeHg exposure through maternal milk on biochemical parameters related to the glutamatergic homeostasis (glutamate uptake by slices) and to the oxidative stress (total and nonprotein sulfhydryl groups, nonprotein hydroperoxides, glutathione peroxidase and catalase activities) in the cerebellum of suckling mice (Swiss albino). The same parameters were also evaluated in the cerebellum of mothers. Our results showed, for the first time, that lactational exposure to MeHg caused a high percent of inhibition (50%) on glutamate uptake by cerebellar slices in pups. Contrarily, this effect was not observed in mothers, which were submitted to a direct oral exposure to MeHg (15 mg/l in drinking water). In addition, behavioral/functional changes were observed in the weaning mice exposed to MeHg. It was observed an increase in the levels of nonprotein hydroperoxides in cerebellum, and this increase was negatively correlated to the glutamate uptake by cerebellar slices. This study indicates that (1) the exposure of lactating mice to MeHg causes inhibition of the glutamate uptake by cerebellar slices in the offspring; (2) this inhibitory effect seems to be related to increased levels of hydroperoxide.

Effects of copper on Enteromorpha flexuosa (Chlorophyta) in vitro

Enteromorpha species are widely used as biomonitors of copper (Cu) contamination in coastal waters, but the effects of Cu at the subcellular level and possible mechanisms of metal resistance are scarcely known. To contribute to the understanding of the Cu accumulation process in macroalgae species, we exposed adult individuals of Enteromorpha flexuosa to 50, 250, and 500 microg Cu/L in seawater for 5 days under controlled conditions. Thereafter, gross photosynthesis rate (GPR) and metal accumulation were measured. Conventional transmission electron microscopy (CTEM) and energy-dispersive X-ray analysis (EDXA) were used to study the metal accumulation process at the cellular level. Treatments with 250 and 500 microg Cu/L were observed to cause an inhibition of the GPR in the algae. Cu accumulation in samples exposed to 500 microgCu/L was 5284+/-561 microg Cu/g (dry wt), whereas in control samples (no Cu addition), accumulation was 9+/-1 microg/g. In cells of plants undergoing the 50 microg Cu/L treatment, the cytoplasm was clearly vacuolated. Thickening of cell walls and increase of relative number of starch granules and of lipid bodies were the main cellular changes observed in plants exposed to 250 and 500 microg Cu/L. EDXA of algae cells after 250 and 500 microg Cu/L exposure detected Cu mainly in vacuole precipitates. Cu was also detected in chloroplasts and in some epiphytic bacteria. It was concluded that E. flexuosa did not avoid penetration of Cu into the cytoplasm and consequently its toxic effects in concentrations of 250 and 500 microg Cu/L. Precipitates containing Cu in vacuoles should be related to a metal immobilization mechanism, minimizing the Cu toxicity for cells. The epiphytic bacteria can act as a biofilter diminishing the availability of free Cu(+2) for algae accumulation.

Behavioural and physiological reactivity to noise in the newborn

OBJECTIVE

To assess the electromyographic (EMG) and behavioural reactivity of a group of newborn infants exposed to noisy stimulation of various intensity recorded in the Paediatric intensive care Unit (PICU).

METHODS

The study was performed at the nursery of the Paediatrics Department (University of Padova) on a group of 21 healthy newborns (mean 39 weeks of gestation), assessed between 24 and 72 h after birth. The study involved taking EMG recordings of the corrugator supercilii muscle and assessing the infant's behaviour at the baseline (15 seconds before stimulation), during noisy stimulation (for 1-2 seconds) and during recovery (15 seconds in three subphases). The noises, previously recorded in PICU, had four different intensities and were administered in random order to all infants. Descriptive analysis and repeated-measures analysis of variance (anova) were performed on the EMG and behavioural data.

RESULTS

The infants demonstrated a significant reaction to the noises both in the EMG recordings and in behavioural changes, especially during intense noisy stimulation. The reaction lasted longer than the stimulation period, preventing the infants from returning to the baseline condition.

CONCLUSIONS

Exposure to high-intensity noise produced in PICU causes evident behavioural and physiological effects (EMG). This is a field of study that could have important repercussions, given the medium- and long-term effects of repeated noise stimulation.