Effect of diet and genotype on the miRNome of mice with altered lipoprotein metabolism

The molecular mechanism by which lipid/lipoprotein biosynthesis is regulated in mammals involves a very large number of genes that are subject to multiple levels of regulation. miRNAs are recognized contributors to lipid homeostasis at the post-transcriptional level, although the elucidation of their role is made difficult by the multiplicity of their targets and the ability of more miRNAs to affect the same mRNAs. In this study, an evaluation of how miRNA expression varies in organs playing a key role in lipid/lipoprotein metabolism was conducted in control mice and in two mouse models carrying genetic ablations which differently affect low-density lipoprotein metabolism. Mice were fed a lipid-poor standard diet and a diet enriched in cholesterol and saturated fat. The results obtained showed that there are no miRNAs whose expression constantly vary with dietary or genetic changes. Furthermore, it appears that diet, more than genotype, impacts on organ-specific miRNA expression profiles.

Effect of Diets on Plasma and Aorta Lipidome: A Study in the apoE Knockout Mouse Model

SCOPE

Specific lipid molecules circulating in plasma at low concentrations have emerged as biomarkers of atherosclerotic risk. The aim of the present study is that of evaluating, in an athero-prone mouse model, how different diets can affect plasma and aorta lipidome.

METHODS AND RESULTS

Thirty-six apoE knockout mice are divided in three groups and feed 12 weeks with diets differing for cholesterol and fatty acid content. Atherosclerosis is measured at the aortic sinus and aorta. Lipids are quantified in plasma and aorta with mass spectrometry. The cholesterol content of the diets is the main driver of lipid accumulation in plasma and aorta. The fatty acid composition of the diets affects plasma levels both of essential (linoleic acid) and nonessential (myristic and arachidonic acid) ones. Lipidomics show a comparable distribution, in plasma and aorta, of the main lipid components of oxidized LDL, including cholesteryl esters and lysophosphatidylcholines. Interestingly, lactosylceramide, glucosyl/galactosylceramide, and individual ceramide species are found to accumulate in diseased aortic segments.

CONCLUSION

Both the cholesterol and fatty acid content of the diets profoundly affect plasma lipidome. Aorta lipidome is likewise affected with the accumulation of specific lipids known as markers of atherosclerosis.

Lack of ApoA-I in ApoEKO Mice Causes Skin Xanthomas, Worsening of Inflammation, and Increased Coronary Atherosclerosis in the Absence of Hyperlipidemia

Background:

HDL (high-density lipoprotein) and its major protein component, apoA-I (apolipoprotein A-I), play a unique role in cholesterol homeostasis and immunity. ApoA-I deficiency in hyperlipidemic, atheroprone mice was shown to drive cholesterol accumulation and inflammatory cell activation/proliferation. The present study was aimed at investigating the impact of apoA-I deficiency on lipid deposition and local/systemic inflammation in normolipidemic conditions.

Methods:

ApoE deficient mice, apoE/apoA-I double deficient (DKO) mice, DKO mice overexpressing human apoA-I, and C57Bl/6J control mice were fed normal laboratory diet until 30 weeks of age. Plasma lipids were quantified, atherosclerosis development at the aortic sinus and coronary arteries was measured, skin ultrastructure was evaluated by electron microscopy. Blood and lymphoid organs were characterized through histological, immunocytofluorimetric, and whole transcriptome analyses.

Results:

DKO were characterized by almost complete HDL deficiency and by plasma total cholesterol levels comparable to control mice. Only DKO showed xanthoma formation and severe inflammation in the skin-draining lymph nodes, whose transcriptome analysis revealed a dramatic impairment in energy metabolism and fatty acid oxidation pathways. An increased presence of CD4⁺ T effector memory cells was detected in blood, spleen, and skin-draining lymph nodes of DKO. A worsening of atherosclerosis at the aortic sinus and coronary arteries was also observed in DKO versus apoE deficient. Human apoA-I overexpression in the DKO background was able to rescue the skin phenotype and halt atherosclerosis development.

Conclusions:

HDL deficiency, in the absence of hyperlipidemia, is associated with severe alterations of skin morphology, aortic and coronary atherosclerosis, local and systemic inflammation.

Speckle tracking echocardiography strain analysis for the assessment and monitoring of myocardial mechanics after pediatric cardiac surgery

Funding Acknowledgements

Type of funding sources: None.

Background. Speckle-tracking echocardiography (STE) is a relatively new ultrasound technique that exploits acoustic reflections and artifacts within the ultrasonic window, with the aim of analyzing global myocardial deformation and segmenting. STE has proved to be more sensitive in identifying a myocardial dysfunction so gained increasing value in the evaluation of congenital heart diseases (CHD) even though its use, in pediatric cardiac surgery, is still limited. The present study aims to evaluate the global and left ventricular (LV) systolic impairment after pediatric cardiac surgery by STE strain (ε) analysis. 

Methods

We prospectively enrolled 120 children undergoing cardiac surgery for CHD. Echocardiography was performed at four different times: pre-operatively, 12-36 hours (Time-1), 3-5 days (Time-2), 6-8 days (Time-3). Images were obtained in the 4-2-and 3 apical chamber’s views to derive LV global and regional (basal/mid/apical) ε values.

Results. We collected data from 332 examinations in 120 children (mean age: 2.33 ±3.91, range: 0-16 years) at different post-operative times. 120 age-matched healthy children (3.1 ± 4.2 years) served as controls. All global, basal, and mid LVε values reduced after surgery; the lowest values were at Time-1 (p < 0.0001) but increased thereafter. At discharge, all global, basal, and mid LVε values persisted lower than pre-operatively and healthy children (p < 0.05). Instead, apical segments (lowest at baseline), increased after surgery (p < 0.0001), but remained lower compared to controls. LV ejection fraction (LVEF) decreased at Time-1 (p = 0.0003) but promptly recovered to Time-2, to standardize at Time-3.

Conclusions. Despite LVEF was normalized by the discharge, STE ε has shown a systolic impairment after cardiac surgery that disclosed a gradual improvement but still uncomplete normalization at discharge.

Regional STE differences revealed a discrepancy base-apex: apical segments, contrary to all the other regions, showed hypercontractility after surgery. The slower recovery of LVε values compared to LVEF, suggests that STE ε analysis may be more accurate in the follow-up of mild LV post-surgical impairment. Abstract Figure. LV ventricular ε values

High frame rate blood speckle tracking echocardiography: left ventricle vortex analyisis in healthy children and in congenital heart disease

Funding Acknowledgements

Type of funding sources: None.

Background

High-frame rate blood speckle tracking (BST) echocardiography is a new method, for the evaluation of intracardiac flow, independent of the insonation angle. Left ventricle, throughout cardiac cycle, creates a vortical flow still poorly analysed in children with congenital heart disease (CHD). Aim of this study is to evaluate the characteristics of left ventricular (LV) vortices in healthy children and in those with CHD.

Methods

Characteristics of LV vortices were acquired on standard 4-chamber view and BST images from 230 healthy children (median age 5.96 years, range 2.9-10.1 years) and 72 children with CHD (median age 1.33 years, IQR 0.2-7.12 years). Both groups were compared after propensity matching. Multiple linear regression was used to identify factors that independently influence vortex characteristics.

Results

Feasibility of vortex imaging was 97% for healthy children and 96.7% for CHD. After propensity matching, there were mild significant differences in vortex distance to apex, distance to interventricular septum, height, width, sphericity index. Indexed by BSA Vortex Area (VAi) was significantly higher on CHD patients than healthy subjects (p < 0.0001).  However, multiple regression analysis exposed significant associations of LV morphology with vortex characteristics: a VAi >0.98 can predict an abnormal LV morphology (Sensibility 73%, Specificity 83%). Furthermore, CHD involving LV volume or pressure overload were both associated with vortices localized closer to the IVS.

Conclusions

LV vortex analysis using high-frame rate BST echocardiography is feasible in healthy children and in those with CHD. Since vortices are associated with LV morphology and are altered in some CHDs, vortices might yield diagnostic and prognostic value. Future studies are necessary to further establish applications of vortex imaging in the clinical setting. Abstract Figure. Vortex in healthy children and in CHD

reString: an open-source Python software to perform automatic functional enrichment retrieval, results aggregation and data visualization

Functional enrichment analysis is an analytical method to extract biological insights from gene expression data, popularized by the ever-growing application of high-throughput techniques. Typically, expression profiles are generated for hundreds to thousands of genes/proteins from samples belonging to two experimental groups, and after ad-hoc statistical tests, researchers are left with lists of statistically significant entities, possibly lacking any unifying biological theme. Functional enrichment tackles the problem of putting overall gene expression changes into a broader biological context, based on pre-existing knowledge bases of reference: database collections of known expression regulation, relationships and molecular interactions. STRING is among the most popular tools, providing both protein–protein interaction networks and functional enrichment analysis for any given set of identifiers. For complex experimental designs, manually retrieving, interpreting, analyzing and abridging functional enrichment results is a daunting task, usually performed by hand by the average wet-biology researcher. We have developed reString, a cross-platform software that seamlessly retrieves from STRING functional enrichments from multiple user-supplied gene sets, with just a few clicks, without any need for specific bioinformatics skills. Further, it aggregates all findings into human-readable table summaries, with built-in features to easily produce user-customizable publication-grade clustermaps and bubble plots. Herein, we outline a complete reString protocol, showcasing its features on a real use-case.

Rupatadine treatment is associated to atherosclerosis worsening and altered T lymphocyte recruitment

No Abstract.

Assessment of the causes of Hg bioaccumulation in the fish of a Mediterranean lagoon subject to environmental management interventions

In a Mediterranean lagoon characterized by high levels of Hg in the sediment, Hg content in commercial fish species was determined, and, in order to establish Hg concentration in the water column, Diffusive Gradient in Thin films technique (DGT) was used. The results allowed to state (1) the disturbance of the surface sediment and its resuspension in the water column did not cause detectable increase in Hg releases, (2) the East basin acted more than the West one in contamination of fish species, (3) the small-sized sea-breams (<400 g) were more contaminated than larger sizes ones (>400 g). We concluded: (1) fish contamination may also depend on direct contact with releases of the contaminant and small, gregarious and less sedentary subjects are more likely to incur releases of Hg; (2) Hg releases can be greater in areas with a relatively low sedimentary organic matter load compared to areas subjected to high density macroalgal mat, regardless of the amount of Hg present in the sediments; (3) wind transport of plant masses in low energy storage areas, may constitute an increase factor of Hg in the sediment. A critical review of the results was made in comparison with the available literature reports and some hypotheses were proposed regarding the possible dynamics and availability of the contaminant.

Autologous CD133+ cells augment the effect of portal embolization

AIM

The standard to treat liver tumors is a resection. When the future liver remnant (FLRV) is below 30% (healthy livers) or 40% (cirrhotic livers or previous chemotherapy), surgery carries the risk of severe complications. Portal vein embolization (PVE) gained a worldwide diffusion as a tool to augment the FLRV. Cell therapies are recent players at the frontiers of medicine. This study presents a clinical experience to evaluate the synergistic effect of combined PVE and autologous CD133+ cells coadministration.

METHODS

Sixteen patients have been enrolled in the study up today. Inclusion criteria were: primary or metastatic liver malignancy with a FLRV<30% or 40%. A baseline volumetric CT-scan was obtained. CD34+ were mobilized to the blood stream by G-CSF administration and collected by immunomagnetic separation. Simultaneously with PVE, cells were administered to the non occluded liver segments. Follow-up CT scans were taken at 30th post treatment day.

RESULTS

The patients (N.=6) showed an increased volume gain (Mann-Whitney test P<0.001, two sided) compared to a set of cases whose treatment was PVE only (N.=10).

DISCUSSION

The use of autologous stem cells as an augmenter of liver regeneration has a clinical potential to improve the resectability of liver tumors.

A human fatty acid amide hydrolase (FAAH) functional gene variant is associated with lower blood pressure in young males

BACKGROUND

Fatty acid amide hydrolase (FAAH) inhibitors, preventing endocannabinoid (EC) degradation, reduce blood pressure (BP) and heart rate in young male (YM) hypertensive rodents. The functional human FAAH 129T gene variant results in reduced protein level and enzymatic activity but its relationship with BP is unknown. This study investigates the relationship among FAAH P129T alleles and cardiovascular features in YMs at baseline and after 9-year follow-up, and in older male obese hypertensive (OH) patients, in whom the EC system (ECS) is overactive.

METHODS

Genotype analysis was performed in 215 Caucasian male students (24 (0.2) years old) and in 185 older OH patients (50 (0.2) years old). YMs were also followed up for 9 years. Clinical and anthropometric variables, BP, cardiac and carotid artery echographic measurements were evaluated.

RESULTS

YMs with the FAAH 129T allele had lower systolic (P = 0.042) and mean BP (P = 0.022), and a trend toward lower diastolic BP (P = 0.06). Such significant association was maintained at follow-up. In contrast, the same allele was not associated with BP in older OH. No association was found with other cardiac and vascular variables.

CONCLUSION

An FAAH defective gene variant results in lower BP in YMs, similar to the findings in young rodents. This effect is lost in older OH patients. Because cannabinoid CB1 receptor blockade is associated with BP reduction in OH patients, EC effects and the use of ECS-interfering drugs is likely to be age and clinical-condition dependent.

Arsenic-resistant bacteria isolated from contaminated sediments of the Orbetello Lagoon, Italy, and their characterization

AIMS

The aim of this study was to isolate arsenic-resistant bacteria from contaminated sediment of the Orbetello Lagoon, Italy, to characterize isolates for As(III), As(V), heavy metals resistance, and from the phylogenetic point of view.

METHODS AND RESULTS

Enrichment cultures were carried out in the presence of 6.75 mmol l(-1) of As(III), allowing isolation of ten bacterial strains. Four isolates, ORAs1, ORAs2, ORAs5 and ORAs6, showed minimum inhibitory concentration values equal or superior to 16.68 mmol l(-1) and 133.47 mmol l(-1) in the presence of As(III) and As(V), respectively. Isolate ORAs2 showed values of 1.8 mmol l(-1) in the presence of Cd(II) and 7.7 mmol l(-1) of Zn(II), and isolate ORAs1 pointed out a value of 8.0 mmol l(-1) in the presence of Cu(II). Analysis of 16S rRNA gene sequences revealed that they can be grouped in the three genera Aeromonas, Bacillus and Pseudomonas. Phylogenetic analysis of the four more arsenic-resistant strains was also performed.

CONCLUSION

Isolates are highly resistant to both As(III) and As(V) and they could represent good candidates for bioremediation processes of native polluted sediments.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides original results on levels of resistance to arsenic and to assigning genera of bacterial strains isolated from arsenic-polluted sediments.

Enhanced Levels of Oxidized Low-Density Lipoprotein Prime Monocytes to Cytokine Overproduction via Upregulation of CD14 and Toll-Like Receptor 4 in Unstable Angina

OBJECTIVES

The purpose of this study was to establish whether oxidized low-density lipoprotein (oxLDL) contributes to cytokine overproduction via upregulation of CD14 and toll-like receptor-4 (TLR-4) expression on circulating monocytes of unstable angina (UA) patients.

METHODS AND RESULTS

Expression of CD14 and TLR-4 on circulating monocytes, and the concentration of plasma oxLDL, (interleukin [IL])-6, IL-1 beta, IL-8, tumor necrosis factor (TNF)-alpha, monocyte chemoattractant protein-1 (MCP-1) were measured in 27 control (C) subjects, 29 patients with stable angina (SA), and 27 with UA. CD14 and TLR-4 expression on monocytes and circulating IL-6, IL-1 beta, and oxLDL were higher in UA than in SA and C subjects (P<0.001). In in vitro experiments, oxLDL increased CD14 and TLR-4 expression (P<0.001) in control monocytes as well as IL-6, IL-1 beta, and at a lower extent TNF-alpha and MCP-1 levels in the supernatant (P from <0.05 to <0.001). The preincubation of sera derived from UA patients but with control monocytes also induced a significant increase of CD14 and TLR-4 expression (P<0.001) and of IL-6 and IL-1 beta production (P<0.001) in the supernatant.

CONCLUSIONS

In UA patients oxLDL may contribute to monocyte overproduction of some cytokines by upregulating CD14 and TLR-4 expression.

Biomarker responses at different levels of biological organisation in crabs (Carcinus aestuarii) experimentally exposed to benzo(alpha)pyrene

The aim of this study was to validate a multi-trial biomarker approach for the evaluation of toxicological risk due to benzo(alpha)pyrene. Carcinus aestuarii, exposed to increasing concentrations of B(alpha)P in the water, was used as the bioindicator organism. A set of biomarkers were tested in order to: identify biological materials for biomarker and residue analysis; determine a group of sensitive techniques for the assessment of PAH contamination; investigate correlation between responses at different levels of biological organisation. The results underlined that BPMO activities in hepatopancreas and gills were a good biomarker of exposure to PAH-type compounds. B esterases activities in hemolymph and porphyrin patterns in excreta could be proposed as a non-destructive approach for evaluating chemical exposure in this species.

Mercury levels along the food chain and risk for exposed populations

Mercury was not regarded as a pollutant of primary importance until many deaths due to mercury poisoning occurred in the 1950s. More recently, adverse health effects have been documented at relatively low exposure levels, and monitoring data must now be interpreted in this light. The Mediterranean basin has been studied in great detail over the past 20 years because of the anomalous natural presence of mercury. Marine animals of this basin have higher mercury body burdens than the same (or similar) species in the Atlantic. The mercury found in marine organisms is mainly in the form of methyl mercury. Long-term and frequent intake of seafood with high mercury levels by populations living in coastal fishing villages is associated with a toxic risk, especially in pregnant women. High blood and hair concentrations of mercury have repeatedly been found in fishermen of Tyrrhenian coastal villages. In some cases these concentrations have been associated with an increase in DNA damage in blood cells. High mercury levels in hair and blood of people from a fishing village of Madeira have also been found. This information deserves renewed scrutiny with regard to preventive efforts needed.

The effect of complete versus incomplete information on odour discrimination in a parasitic wasp

We studied the function of learning in the parasitoid Leptopilina heterotoma by looking at discrimination of odour stimuli used in foraging for a host. To optimize the rate of encounters with hosts, these parasitoids are expected to assess the extent to which variation in host-substrate odours is reliably associated with variation in the presence of hosts, that is, substrate profitability. Where the association is reliable, parasitoids should attend to variation in odours and discriminate between them; where it is not, they should ignore it. We hypothesized that foraging decisions are based on the completeness of information the animal has about differences in substrate profitabilities. Our laboratory studies showed that discrimination and non-discrimination of odour stimuli are dynamic behavioural decisions that can be related to the degree of substrate variation and to an animal's informational state. In wind-tunnel studies, females learned to discriminate between odours from substrates that were qualitatively different, for example, between odours from apple and pear substrates or between yeast substrates with different C6 compounds added. They did not discriminate when differences were small (e.g. between odours from two apple varieties or between yeast patches with different concentrations of ethyl acetate), unless unrewarding experiences provided evidence of the absence of hosts in one of the substrates. Hence, we suggest that non-discrimination between odour stimuli in L. heterotoma is not a lack of ability to discriminate but a functional decision by the parasitoid. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.

A putative new peptide synthase operon in Bacillus subtilis: partial characterization

A large operon-type structure has been located between the gltA and citB loci on the Bacillus subtilis chromosome. On the basis of the analysis of the 25 kb sequenced so far, it potentially encodes at least three large proteins which contain structural motifs associated with the subunits of all characterized peptide synthases. The amino acid recognition specificity of this new peptide synthase is discussed in the light of sequence homology with other synthases.

Cytogenetic monitoring of fishermen with environmental mercury exposure

Due to high mercury levels in many Mediterranean aquatic organisms, people who live in this area and consume large amounts of seafood are exposed to a toxicological hazard. A group of 51 fishermen exposed to mercury through eating contaminated seafood from the northern Tyrrhenian Sea underwent cytogenetic monitoring. This work is part of a research project consisting of the evaluation of micronuclei (MN), chromosomal aberrations (CA) and sister-chromatid exchanges (SCE) in peripheral blood lymphocytes. Here we present data on mercury levels in blood and on micronucleus frequencies in peripheral blood lymphocytes of fishermen. The range of mercury concentrations in blood was 10.08-304.11 ng/g fresh weight, the average was 88.97 +/- 54.09 ng/g. Micronucleus frequency was defined with at least 2000 binucleated cells scored for each person; the average was 8.74 +/- 2.56 expressed on 1000 binucleated cells. A statistical correlation was found between MN frequency and total mercury concentration in blood (p = 0.00041, r = 0.674), as well as between MN frequency and age (p = 0.017). No other parameters taken into account correlated with MN frequency.

A new human growth hormone production process using a recombinant Bacillus subtilis strain

We constructed a series of hybrid plasmids which directed the synthesis of different human growth hormone (hGH) precursor sequences in Bacillus subtilis. In addition to the 191 amino acids of the hormone, the precursors had in common an amino-terminal extension characterized by the presence of a methionine at position 1 and of the tetrapeptide Ile-Glu-Gly-Arg preceding the first residue (Phe) of hGH. The sequence between the methionine and the tetrapeptide was specific for each precursor and, because of the presence of charged residues, conferred particular properties to the molecules. Long homopolymeric tail-containing precursors such as MRRRRRRIILM-IEGR appeared insoluble whereas shorter sequences of the type MRR-IEGR and MEELM-IEGR augmented the solubility of the precursors with respect to Met-hGH. The soluble precursors could be easily purified from the bulk proteins taking advantage of the charged residues present on the N-terminal tail. After purification, the natural hGH was obtained by treating the precursors with the protease Factor Xa which cleaves after the arginine residue of the tetrapeptide IEGR. A protocol for the production and purification of authentic hGH from a strain expressing one of these soluble precursors is reported.

Identification of sulfurtransferase enzymes in Azotobacter vinelandii

Rhodanese and 3-mercaptopyruvate sulphurtransferase have been identified in A. vinelandii. Two distinct active fractions of the two sulphur transferases were obtained after FPLC ion-exchange chromatography of material partially purified from crude extracts. Rhodanese has been purified to homogeneity, and it consists of one polypeptide chain of Mr ca 25,000. A partial purification of 3-mercaptopyruvate sulphurtransferase was obtained.

Structural analysis of poly(ADP-ribose)polymerase in higher and lower eukaryotes

A phylogenetic survey for the poly(ADP-ribose)polymerase has been conducted by analyzing enzyme activity in various organisms and determining the structure of the catalytic peptides by renaturation of functional activities of the enzyme in situ after electrophoresis in denaturing conditions (activity gel). The enzyme is widely distributed in cells from all different classes of vertebrates, from arthropods, mollusks and plant cells but could not be detected in echinoderms, nematodes, platyhelminths, thallophytes (including yeast) and bacteria. The presence on activity gels of a catalytic peptide with Mr = 115,000-120,000 was demonstrated in vertebrates, arthropods and mollusks but no activity bands were recovered in many lower eukaryotes, in plant cells and bacteria. By using an immunological procedure that used an antiserum against homogeneous calf thymus poly(ADP-ribose) polymerase, common immunoreactive peptides were visualized in mammals, avians, reptiles, amphibians and fishes, while lacking in non-vertebrate organisms. Our results indicate that the structure of poly(ADP-ribose) polymerase is conserved down to the mollusks suggesting its important role for DNA metabolism of multicellular organisms.

Calcium and polyphosphoinositides: their distribution in relation to the membrane changes occurring in the head of boar spermatozoa

Ejaculated boar spermatozoa, previously incubated in a rigorously Ca++-free medium, were exposed to Ca++ for different incubation times and processed for the detection of Ca++ localization by a pyroantimonate technique. The distribution of polyphosphoinositides, anionic phospholipids natural constituents of membrane known to bind Ca++, was investigated using a specific cytochemical probe, i.e., neomycin conjugated with horseradish peroxidase. The in situ localizations thus obtained revealed: short exposure to Ca++ ions (10 min) evocated a Ca++-induced release of calcium from the nonmitochondrial intracellular store, i.e., the outer acrosomal membrane; a more prolonged exposure (20 min) triggered the occurrence of fusional and exocytotic events, that appeared to be morphologically related to the acrosome reaction; the outer acrosomal membrane, which is the fusigenic sperm membrane, was the elective site of the neomycin/peroxidase labeling. When assayed for the presence of a phospholipase C-like activity, the detergent extract obtained from boar spermatozoa exhibited substantial amount of p-nitrophenyl-phosphorylcholine hydrolyzing activity. The results, on the whole, allow us to suggest a relationship between Ca++ and polyphosphoinositides turnover in the events triggering the acrosome reaction, the exocytotic process peculiar to mammalian spermatozoa.

Ca++ localization in boar spermatozoa by the pyroantimonate technique and X-ray microanalysis

Intracellular, loosely bound Ca++ has been localized electron microscopically in freshly ejaculated boar spermatozoa by in situ precipitation with potassium antimonate. Ca++ was identified as the cation precipitated by testing the EGTA-sensitivity of the precipitates and by X-ray microprobe analysis. The data obtained revealed that the outer acrosomal membrane is the preferential site for Ca++ precipitation in the sperm head.

Variation in DNA ligase structure during repair and replication processes in monkey kidney cells

Using a method that detects catalytically active DNA ligase in NaDodSO4-polyacrylamide gels (activity gels) we have characterized ligase produced in CV1-P monkey kidney cells infected with SV40 or treated with mitomycin C. Purification on hydroxylapatite columns of DNA ligase from control cells results in two peaks of activity called ligases I and II, respectively. Analysis of ligase I on activity gels revealed major catalytic peptides with Mr of 120, 110, 70 and 58 kDa, while analysis of ligase II revealed two major peptides of 65 and 58 kDa. Infecting CV1-P cells with SV40 produced a significant increase in the 120, 110, 70 and 58 kDa peptides while treating them with mitomycin C produced a significant increase in the 70 and 58 kDa peptides and a decrease in the 120 and 110 kDa ones. Autoproteolysis of partially purified ligase under several conditions resulted in an increase in the 58 kDa peptide and in the disappearance of other peptides. These results suggest that at least one active polypeptide is common to ligases I and II.

Morphological evidence for calcium stores at Sertoli-Sertoli and Sertoli-spermatid interrelations

Potassium pyroantimonate technique has been employed to localize calcium ultrastructurally at Sertoli-Sertoli and Sertoli-spermatid junctional specializations. Identification of Ca++ as the major cation precipitated was performed by EGTA sensitivity and X-ray microprobe analysis. Ca++ deposits have been demonstrated in the endoplasmic reticulum cisternae underlying junctional complexes and along the plasma membranes of both Sertoli and germ cells.

Structure and possible functional role of septate junctions in the ovotestis of a pond snail: inter-Sertoli junctions

Junctions between Sertoli cells, which form a continuous layer at the periphery of the 'acinus' in the ovotestis of Biomphalaria glabrata (mollusc gastropod), have been studied with conventional sections, lanthanum impregnation, replicas and scanning analysis of unstained sections. Extensive undulating septate junctions link Sertoli cells, which surround the various stages of spermatid differentiation. The morphology of the pleated septate junctions here presented indicates a possible role as a permeability barrier, which might result from the peculiar organization of the septa. The junctional complex is formed of areas where septa are parallel and regularly spaced, alternating with areas where septa separate and assemble with others, thus creating a complex system of channels, completely compatible with the sealing properties expected for these junctions. The morphology of septa, their possible anchorage within the membranes, and the interconnections linking the closely parallel septa are presented.

Evidence that a Ca2+ chelator and a calmodulin blocker interfere with the structure of inter-Sertoli junctions

Ca2+ dependence of tight junction structure has been well documented in cultured epithelial tissues, and regulatory mechanisms have been identified. To analyse the possible control exerted on inter-Sertoli junctions, we exposed guinea-pig seminiferous tubules to the presence of a Ca2+ chelator (EGTA) and to a calmodulin blocker (Trifluoperazine, TFP) in vitro, for times ranging from 30 to 120 min. We observed the morphology of junctional complexes and the basal cytoplasmic regions in sections and replicas. Sertoli cell response to Ca2+ depletion involved several events: retraction of cells toward the base of the tubule and a consequent stretching of the points of fusion, augmented density of the cytoplasm, and destabilization of the array of intramembrane particles. Exposure of tubules to TFP resulted in disruption of the interactions between actin filaments and membrane junctional specialization, as well as a disorganization of other cytoskeletal elements. Thus, in vitro, junction integrity appears to be related to Ca2+ level, and Ca2+ depletion apparently interferes with Ca2+ distribution inside the cell and on microfilaments involved in junction regulation. Our results do not provide direct evidence for any particular mechanism of action of TFP, but a multiple effect is evident. TFP, which affects Ca2+ regulation and membrane fluidity, probably acts indirectly on junction-associated filaments. Both the experimental conditions tested suggest a Ca2+-mediated regulatory role of microfilaments of this complex junction.

[Preliminary data on the endocrinologic evaluation of thalassemic adolescents]

Endocrine disfunction are well known in young patients with thalassaemia major and are mainly due to iron overload. Gonadotrophin releasing hormone (GnRH) was administered to 13 boys aging more than 14 years and to 13 girls aging more than 13 years to assess pituitary function. Human Chorionic gonadotrophin (HCG) was also administered to 13 boys to evaluate their gonadal function. Most of the patients had evidence of pituitary hypofunction and in 4 boys there was evidence of gonadic failure. This study is mandatory for a correct therapeutic approach.

[Critical evaluation of the causes of death in thalassemic subjects]

We discuss 25 cases of death observed from 1971 to 1983 in a casistic of 155 patients with Thalassaemic Syndrome. Anemia as a cause of death is disappearing, new triggers are involved such as Yersinia Enterocolitica who can cause severe sepsis even in non-splenectomized patients. Iron overload appears to be the most severe complication in the second decade.

Responsiveness of testis morphology to chemotherapy in childhood leukemia

The appearance of seminiferous tubules and interstitial cells of children, aged 2.5 to 13 years, affected by acute lymphoblastic leukemia was analyzed in sections. The testicular biopsies were performed at the end of therapy (vincristine, prednisone, L-asparaginase, 6-mercaptopurine, intrathecal methotrexate), which was affected for the same period and at the same doses. Three age groups were considered (I, 2.5 to 5 years; II, 6 to 9 years; III, 12 to 13 years). Age groups I and II presented damage of some tubules (25-35%) and areas of degeneration. Histometric analysis performed for A type spermatogonial population gave a mean value corresponding to controls in age group I and a mean value significantly lower with respect to controls in age group II. Moreover, age group II presented a lack of increase in tubular cross section. These results suggest that there is a vulnerability both of whole tubules and of some areas of Sertoli cells and germ cels to cytotoxic-induced damage. Leydig cells appear to be the cells least sensitive to drugs, and hormonal data indicate that the hypothalamic pituitary function appears to be intact, despite chemotherapy. Long-term prospective studies of reproductive function in children receiving cancer chemotherapy are needed to determine the magnitude and duration of damage resulting from therapeutic treatment.

Chemotherapy does not affect the development of inter-Sertoli junctions in childhood leukaemia

The inter-Sertoli junctions of children aged between 5 and 12 years, affected by acute lymphoblastic leukaemia, were analyzed in sections and freeze-fracture replicas. The testicular biopsies were performed at the end of therapy, when patients were in continuous remission for over 30 months. Chemotherapy does not seem to affect the development of junctions that were studied in sections and freeze fracture. Two age groups were considered (I, 5 to 8 years; II, 9 to 12 years). In age group I, oval Sertoli cells were connected by occasionally focal points of fusion, which in replicas appeared as scattered, interrupted ridges on the P face and grooves on the corresponding E face. In age group II Sertoli cells presented cytoplasmic extensions and interdigitations. Tight junctions appeared close to one another in conventional sections. Freeze fracture evidenced extensive although isolated areas formed by intervining strands. Lanthanum penetrated freely the intercellular spaces and gap junctions were observed in both age groups. The results suggest that tight junctions formation is initiated long before puberty; a progression in the complexity of the strand organization is present as the tubules mature; the strands reorganize in parallel and continuous rows only at puberty.

Morphological changes of Leydig cells in men with altered plasma testosterone and gonadotropin levels

The ultrastructural features of Leydig cells in patients with high serum LH and low serum testosterone are described. The results are compared with the structure of Leydig cells in normal conditions and after treatment with human chorionic gonadotropin (hCG) according to data existing in the literature. The continuous overstimulation of Leydig cells by higher levels of LH apparently induces significant modifications in many of the morphological elements characteristic of these cells. However, these differences were not constantly present in the cases observed. The abundance and the large size of mitochondria were the only common characteristics in the patients studied.