Photo-activated raster scanning thermal imaging at sub-diffraction resolution

Active thermal imaging is a valuable tool for the nondestructive characterization of the morphological properties and the functional state of biological tissues and synthetic materials. However, state-of-the-art techniques do not typically combine the required high spatial resolution over extended fields of view with the quantification of temperature variations. Here, we demonstrate quantitative far-infrared photo-thermal imaging at sub-diffraction resolution over millimeter-sized fields of view. Our approach combines the sample absorption of modulated raster-scanned laser light with the automated localization of the laser-induced temperature variations imaged by a thermal camera. With temperature increments ∼0.5-5 °C, we achieve a six-time gain with respect to our 350-μm diffraction-limited resolution with proof-of-principle experiments on synthetic samples. We finally demonstrate the biological relevance of sub-diffraction thermal imaging by retrieving temperature-based super-resolution maps of the distribution of Prussian blue nanocubes across explanted murine skin biopsies.

μMAPPS: a novel phasor approach to second harmonic analysis for in vitro-in vivo investigation of collagen microstructure

Second Harmonic Generation (SHG) is a label-free imaging method used to monitor collagen organization in tissues. Due to its sensitivity to the incident polarization, it provides microstructural information otherwise unreachable by other intensity based imaging methods. We develop and test a Microscopic Multiparametric Analysis by Phasor projection of Polarization-dependent SHG (μMAPPS) that maps the features of the collagen architecture in tissues at the micrometer scale. μMAPPS retrieves pixel-by-pixel the collagen fibrils anisotropy and orientation by operating directly on two coupled phasor spaces, avoiding direct fitting of the polarization dependent SHG signal. We apply μMAPPS to fixed tissue sections and to the study of the collagen microscopic organization in tumors ex-vivo and in-vivo. We develop a clustering algorithm to automatically group pixels with similar microstructural features. μMAPPS can perform fast analyses of tissues and opens to future applications for in-situ diagnosis of pathologies and diseases that could assist histo-pathological evaluation.

Mesenchymal stem cells from tumor microenvironment favour breast cancer stem cell proliferation, cancerogenic and metastatic potential, via ionotropic purinergic signalling

Interaction between tumor cells and the microenvironment is key in initiation, progression, and invasiveness of cancer. In particular, mesenchymal stem cells (MSCs) are recruited to the sites of developing tumors, thus promoting metastasis formation. Although it is well known that MSCs migrate and integrate in the tumor microenvironment (TME), their fate and function inside the tumor is still not clear. In this study, we analyzed the role played by MSCs in breast cancer oncogenesis. Data indicate that interaction of breast cancer cells with MSCs results in an increased proliferation and metabolic activity of breast cancer cells, partially due to MSC-derived microvesicles that are shed in the TME. Moreover, we addressed the question of whether we could modulate such interaction by acting on P2X-mediated intercellular communication. By inhibiting P2X-mediated purinergic signaling, we succeeded in reducing both the cancerogenic as well as the metastatic potential of breast cancer cells co-cultured with MSCs, in 2D as well as in 3D in vitro models. Data obtained demonstrate for the first time that the trophic effect of MSCs on breast cancer cell growth is exerted via ionotropic purinergic signaling, thus suggesting the inhibition of the purinergic signaling system as a potential target for therapeutic intervention.

The microphysics of collisionless shock waves

Collisionless shocks, that is shocks mediated by electromagnetic processes, are customary in space physics and in astrophysics. They are to be found in a great variety of objects and environments: magnetospheric and heliospheric shocks, supernova remnants, pulsar winds and their nebulæ, active galactic nuclei, gamma-ray bursts and clusters of galaxies shock waves. Collisionless shock microphysics enters at different stages of shock formation, shock dynamics and particle energization and/or acceleration. It turns out that the shock phenomenon is a multi-scale non-linear problem in time and space. It is complexified by the impact due to high-energy cosmic rays in astrophysical environments. This review adresses the physics of shock formation, shock dynamics and particle acceleration based on a close examination of available multi-wavelength or in situ observations, analytical and numerical developments. A particular emphasis is made on the different instabilities triggered during the shock formation and in association with particle acceleration processes with regards to the properties of the background upstream medium. It appears that among the most important parameters the background magnetic field through the magnetization and its obliquity is the dominant one. The shock velocity that can reach relativistic speeds has also a strong impact over the development of the micro-instabilities and the fate of particle acceleration. Recent developments of laboratory shock experiments has started to bring some new insights in the physics of space plasma and astrophysical shock waves. A special section is dedicated to new laser plasma experiments probing shock physics.

PCR-RFLP genotyping protocol for chicken Mx gene G/A polymorphism associated with the S631N mutation

The Mx (myxovirus resistance) gene codes for a protein with antiviral activity. Non-synonymous G/A polymorphism at position 2032 of chicken Mx cDNA results in a change at amino acid 631 of the Mx protein. This mutation has been shown to affect the antiviral activity of the Mx molecule, although recent studies have not confirmed this effect in response to some influenza strains. Nevertheless, the G/A polymorphism could be important for the chicken's response to other viruses. A robust PCR-RFLP protocol for genotyping chicken Mx gene polymorphism associated with the S631N mutation was developed. The F primer anneals to the last intron of the Mx gene, and the R primer anneals to the last exon of the gene, with an expected PCR product of 299 bp. PCR products were digested with Hpy8I. This enzyme cuts the sequence 5'-GTN|NAC-3', 2 bp downstream of the Mx polymorphism for the G allele, whereas the fragment containing the A allele is not cleaved. One hundred and twenty-seven chickens (commercial broilers, White Leghorn and New Hampshire) were genotyped using this protocol, and genotyping data were validated by sequencing. Full identity of results between the two genotyping methods was observed for all 127 samples, proving the reliability and robustness of this PCR-RFLP protocol.

Avian TAP genes: detection of nucleotide polymorphisms and comparative analysis across species

TAP1 and TAP2 genes code for the two subunits of the transporter associated with antigen processing (TAP), and in chicken they are located between the two MHC class I genes. Using primers based on chicken sequences, the genomic regions corresponding to chicken TAP1 exons 6 to 7 and TAP2 exons 4 to 6 (which encode portions of the chicken TAP1 and TAP2 molecules corresponding to the human peptide-binding regions) were amplified and sequenced from chicken (70 birds), turkey (24), pheasant (6), and guinea fowl (7). A total of 80 within-species single nucleotide polymorphisms (SNPs) were identified. None of the chicken SNPs detected here was present in public databases. The SNP frequencies in chicken were 9.57 SNP/kb in TAP1 and 19.16 SNP/kb in TAP2, while turkey showed similar SNP frequencies in the two genes. Putative amino acid sequences were inferred to identify non-synonymous substitutions. The alignment of the consensus polypeptide sequences showed that most of the amino acid variations were conserved or semi-conserved substitutions. In conclusion, a high variability in the level of nucleotide polymorphism was observed within the two genes, with chicken showing the highest polymorphism rate in both genes. Most of the SNPs identified were within introns, and a general conservation of both amino acid numbers and characteristics of residues among and within the species was found. These data underline the functional importance of these molecules, but also suggest their capacity to bind different antigenic peptides.

Single Nucleotide Polymorphism Discovery in the Avian Tapasin Gene

Tapasin is a transmembrane glycoprotein located in the endoplasmic reticulum. Its function is to assist the assembly of major histocompatibility complex class I molecules. The chicken Tapasin gene includes 8 exons and is localized inside the major histocompatibility complex between the 2 class IIbeta genes. The aim of the current study was the estimation of single nucleotide polymorphism frequency within the avian Tapasin gene. The Tapasin gene sequence from exon 5 to exon 6 was amplified for the chicken, turkey, and pheasant, and sequences of different lengths were obtained. The sequence analysis based on PolyBayes identified 25 putative single nucleotide polymorphism sites when the 3 species were compared. The coding sequences were further translated and analyzed to identify amino acid substitutions. The results indicated that polymorphisms within this region of the gene was mainly observed in the heterozygous state. The level of conservation of the Tapasin gene sequence among species is likely to be related to the functional importance of the gene.

Myelin deterioration in Twitcher mice: motor evoked potentials and magnetic resonance imaging as in vivo monitoring tools

We have used magnetic resonance imaging (MRI) and motor evoked potentials (MEPs) for monitoring disease progression within the CNS of the Twitcher mouse, the murine model for globoid cell leukodystrophy (GLD). GLD is a lysosomal storage disorder, resulting from galactocerebrosidase deficiency, causing central and peripheral myelin impairment, leading to death, usually during early infancy. Neuroradiological, electrophysiological, and pathological parameters of myelin maturation were evaluated in Twitcher mice between postnatal days 20 and 45. Healthy controls showed a gradual-appearance MRI T2-weighted hypointensity of the corpus callosum (CC) starting at about P30 and ending at about P37, whereas MRI of age-matched Twitcher mice showed a complete loss of the CC-related MRI signal. MEPs allowed the functional assessment of myelin maturation within corticospinal motor pathways and showed a progressive deterioration of MEPs in Twitcher mice with increased central conduction time (CCT; 5.12 +/- 0.49 msec at P27 to 6.45 +/- 1.96 msec at P32), whereas physiological CCT shortening was found in healthy controls (3.01 +/- 0.81 msec at P27 to 2.5 +/- 0.27 msec at P32). These findings were not paralleled by traditional histological stainings. Optical observation of Bielchowsky and Luxol fast blue-PAS stainings showed mild axonal/myelin deterioration of the Twitcher brain within this time frame. Our results demonstrate that serial MRI and MEP readings are sensitive evaluation tools for in vivo monitoring of dysmyelination in Twitcher mice and underscore their potential use for longitudinal evaluation of the therapeutic impact of gene and cell therapies on these animals.

Neuroprotective Effect of Simvastatin in Stroke: A Comparison Between Adult and Neonatal Rat Models of Cerebral Ischemia

Statins, the most widely used lipid lowering drugs, have been demonstrated to play a protective role in stroke. Animal studies confirmed the observations obtained in clinical trials and provided additional data on the putative mechanism/s of action underlying this beneficial effect. We have shown that simvastatin reduced the size of the infarct to a different extend, according to the animal model used. Indeed, in the rat neonatal model of hypoxia/ischemia simvastatin affords protection only when is administered before the ischemic insult. In contrast, in adult rats bearing middle cerebral artery occlusion, simvastatin exerted its beneficial effect on brain injury when injected for 3 days either before or after induction of ischemia. Studies carried out to determine the therapeutic window of simvastatin demonstrated that the protective effect is observed after a single dose and when the drug is administered within 3-6 hours after ischemia. Simvastatin-dependent activation of eNOS has been claimed to be one of the main mechanisms responsible for neuroprotection. This hypothesis is confirmed in the adult animal model where eNOS is activated by either pre- or post- simvastatin treatment but is not supported by the data obtained in the neonate where eNOS activity is not affected by drug treatment. These observations suggest that the protective effect of simvastatin on stroke may be mediated by multiple mechanisms as can be expected by its pleiotropic effects.

MultiexponentialT2-relaxation analysis in cerebrally damaged rats in the absence and presence of a gadolinium contrast agent

An analysis of the multiexponential relaxation of transverse nuclear magnetization with and without a gadolinium-based paramagnetic contrast agent in spontaneously hypertensive stroke-prone rats (SHR-SP) and in the rat model of ischemia induced by middle cerebral artery occlusion is described. From the multiexponential relaxation, the presence of two T(2) relaxation times in the range of 0.03-0.5 s, T(2A) (shortest) and T(2B) (longest), with very different relative weights (respectively, A and B), is evidenced. In our models of cerebral damage, the changes in A and B were more evident than those in T(2A) and T(2B). The two T(2) values were interpreted as belonging to water molecules in two different compartments; therefore, the difference between the damaged and normal regions revealed by means of standard T(2)-weighted images is suggested to be due to a different water distribution in the two compartments, rather than different T(2)'s. The T(2) relaxation in the SHR-SP stroke model is analyzed for the first time using a multiexponential method. The power of a detailed analysis of MRI relaxation times is confirmed by the correspondence between the revealed changes in T(2A), T(2B), A and B, and the known T(2)W and DWI results about blood-brain barrier functionality.

Proteins of rat serum, urine, and cerebrospinal fluid: VI. Further protein identifications and interstrain comparison

We have investigated the biological fluids--serum, cerebrospinal fluid, and urine--of three strains of rats; the present data extend our database (also available on-line) and may be of interest for pharmacological and toxicological investigation. Specifically, we have defined reference maps of the major protein components in cerebrospinal fluid and urine. Compartment-specific isoforms were recognized for transferrin and transthyretin. Mass spectrometric data established the cleavage site of the signal peptide and identified the N-terminal blocking group of prostaglandin D synthase from rat cerebrospinal fluid. A previously undescribed member of the family of low molecular mass rat urinary proteins was characterized as containing a sequence similar, but not identical, to the N-terminal region of rat urinary protein-2 (RUP-2), and divergent from RUP-1.

Magnesium inhibits arterial thrombi after vascular injury in rat: in vivo impairment of coagulation

Magnesium deficiency is associated with a high frequency of cardiac arrhythmia, hypertension and sudden ischemic death. We investigated the if vivo effects of intravenous magnesium administration in a rat model of chemically induced (FeCl3) carotid thrombosis. The infusion of magnesium sulfate (MgSO4) before the topical application of FeCl5 prevented thrombus formation at concentrations of 0.3 M and 0.6 M, and delayed it even at 0.15 M. Similar results were obtained with MgCl2. The infusion of MgSO4 0.6 M seven minutes after FeCl3 application delayed but did not prevent thrombus formation. MgSO4 slightly reduced platelet aggregation ex vivo without affecting plasma clotting tests, but in vivo blood clotting time was markedly prolonged (tail transection method), thus indicating profoundly impaired coagulation. These data provide a rationale for the use of magnesium as an antithrombotic agent. but its pharmacological effect critically depends on the timing of administration.

Proteins of rat serum, urine, and cerebrospinal fluid: VI. Further protein identifications and interstrain comparison

We have investigated the biological fluids--serum, cerebrospinal fluid, and urine--of three strains of rats; the present data extend our database (also available on-line) and may be of interest for pharmacological and toxicological investigation. Specifically, we have defined reference maps of the major protein components in cerebrospinal fluid and urine. Compartment-specific isoforms were recognized for transferrin and transthyretin. Mass spectrometric data established the cleavage site of the signal peptide and identified the N-terminal blocking group of prostaglandin D synthase from rat cerebrospinal fluid. A previously undescribed member of the family of low molecular mass rat urinary proteins was characterized as containing a sequence similar, but not identical, to the N-terminal region of rat urinary protein-2 (RUP-2), and divergent from RUP-1.

Effects of androgen supplementation of hormone replacement therapy on the vascular reactivity of cerebral arteries

OBJECTIVE

To determine the effect of the androgen supplementation of hormone replacement therapy (HRT) on the vascular reactivity of cerebral arteries.

DESIGN

Open randomized study.

SETTING

Healthy volunteers in an academic research environment.

PATIENT(S)

Forty postmenopausal women who were treated with sequential HRT (transdermal E2 50 microg/d + medroxyprogesterone acetate 10 mg/d for 12 days every other month) for > or =1 year and < or =5 years.

INTERVENTION(S)

Testosterone undecanoate (40 mg/d, p.o.) was randomly administered to 20 patients during ongoing HRT; the other 20 served as controls. Doppler evaluations of the internal carotid and middle cerebral arteries were performed together with lipid levels assessments. A visual analogue scale (VAS) was used to evaluate various parameters relating to sexual life and well-being.

MAIN OUTCOME MEASURE(S)

Pulsatility index (PI) of the arteries, VAS assessment of psychophysical well-being.

RESULT(S)

The administration of testosterone undecanoate during HRT induced an increase in the PI of the middle cerebral artery and a reduction of high-density lipoprotein cholesterol. Sexual desire and satisfaction were greatly improved.

CONCLUSION(S)

In postmenopausal women, androgen supplementation during HRT can partially counteract the beneficial effects of estrogens on cerebral vascular reactivity and lipid profiles, but sexual desire and satisfaction are greatly improved.

Transcriptional regulation of plasminogen activator inhibitor type 1 gene by insulin: insights into the signaling pathway

Impairment of the fibrinolytic system, caused primarily by increases in the plasma levels of plasminogen activator inhibitor (PAI) type 1, are frequently found in diabetes and the insulin-resistance syndrome. Among the factors responsible for the increases of PAI-1, insulin has recently attracted attention. In this study, we analyzed the effects of insulin on PAI-1 biosynthesis in HepG2 cells, paying particular attention to the signaling network evoked by this hormone. Experiments performed in CHO cells overexpressing the insulin receptor indicate that insulin increases PAI-1 gene transcription through interaction with its receptor. By using inhibitors of the different signaling pathways evoked by insulin-receptor binding, it has been shown that the biosynthesis of PAI-1 is due to phosphatidylinositol (PI) 3-kinase activation, followed by protein kinase C and ultimately by mitogen-activated protein (MAP) kinase activation and extracellular signal-regulated kinase 2 phosphorylation. We also showed that this pathway is Ras-independent. Transfection of HepG2 cells with several truncations of the PAI-1 promoter coupled to a CAT gene allowed us to recognize two major response elements located in the regions between -804 and -708 and between -211 and -54. Electrophoretic mobility shift assay identified three binding sites for insulin-induced factors, all colocalized with putative Sp1 binding sites. Using supershifting antibodies, the binding of Sp1 could only be confirmed at the binding site located just upstream from the transcription start site of the PAI-1 promoter. A construct comprising four tandem repeat copies of the -93/-62 region of the PAI-1 promoter linked to CAT was transcriptionally activated in HepG2 cells by insulin. These results outline the central role of MAP kinase activation in the regulation of PAI-1 induced by insulin.

Effect of valsartan on angiotensin II-induced plasminogen activator inhibitor-1 biosynthesis in arterial smooth muscle cells

Previous studies have shown that angiotensin II stimulates the synthesis of plasminogen activator inhibitor-1 in cultured vascular cells, which suggests that activation of the renin-angiotensin system may impair fibrinolysis. We have investigated the effects of angiotensin II and of valsartan, a recently developed angiotensin II antagonist that is highly specific and selective for the angiotensin II subtype 1 receptor, on plasminogen activator inhibitor-1 secretion by smooth muscle cells isolated from rat and human vessels. Angiotensin II induced a time- and concentration-dependent increase of plasminogen activator inhibitor activity in supernatants of rat aortic cells, which reached a plateau after 6 hours of incubation with 100 nmol/L angiotensin II (2.4+/-0.6-fold over control value; P:<0.001). The angiotensin II-induced plasminogen activator inhibitor activity was inhibited, in a concentration-dependent manner, by valsartan with an IC(50) value of 21 nmol/L. Valsartan fully prevented the angiotensin II-induced increase in plasminogen activator inhibitor-1 protein and mRNA. Furthermore, angiotensin II doubled the secretion of plasminogen activator inhibitor-1 by smooth muscle cells obtained from human umbilical and internal mammary arteries, and valsartan fully prevented it. Angiotensin II did not affect the secretion of tissue plasminogen activator antigen by any of the cell systems tested. Thus, valsartan effectively inhibits angiotensin II-induced plasminogen activator inhibitor-1 secretion without affecting that of tissue plasminogen activator in arterial rat and human smooth muscle cells.

Acute-phase proteins before cerebral ischemia in stroke-prone rats: identification by proteomics

BACKGROUND AND PURPOSE

A high degree of proteinuria has been reported in stroke-prone spontaneously hypertensive rats (SHRSP). We studied the effect of salt loading on the detailed protein pattern of serum and urine in 3 rat strains: Wistar-Kyoto, spontaneously hypertensive rats, and SHRSP, an inbred animal model for a complex form of cerebrovascular disorder resembling the human disease.

METHODS

Rats were given a permissive diet and received 1% NaCl in drinking water. The protein pattern in body fluids was assessed over time by 2-dimensional electrophoretic analysis. Brain alterations were monitored by MRI and histology.

RESULTS

Several proteins were excreted in urine after weeks of treatment and in advance of stroke: transferrin, hemopexin, albumin, alpha(2)-HS-glycoprotein, kallikrein-binding protein, alpha(1)-antitrypsin, Gc-globulin, and transthyretin. Markers of an inflammatory response, including very high levels of thiostatin, were detected in the serum of SHRSP at least 4 weeks before a stroke occurred.

CONCLUSIONS

In SHRSP subjected to salt loading, an atypical inflammatory condition and widespread alterations of vascular permeability developed before the appearance of anomalous features in the brain detected by MRI. Urinary concentrations of each of the excreted serum proteins correlated positively with time before stroke occurred.

Fluvastatin inhibits basal and stimulated plasminogen activator inhibitor 1, but induces tissue type plasminogen activator in cultured human endothelial cells

The effects of fluvastatin, a synthetic hydroxymethylglutaryl coenzyme A (HMG-CoA) inhibitor, on the biosynthesis of tissue plasminogen activator (t-PA) and of its major physiological inhibitor (plasminogen activator inhibitor type 1, PAI-1) were investigated in cultured human umbilical vein endothelial cells (HUVEC). Fluvastatin (0.1 to 2.5 microM), concentration-dependently reduced the release of PAI-1 antigen by unstimulated HUVEC, subsequent to a reduction in PAI-1 steady-state mRNA levels and de novo protein synthesis. In contrast, it increased t-PA secretion. The drug also reduced PAI-1 antigen secreted in response to 10 microg/ml bacterial lipopolysaccharide (LPS), 100 U/ml tumour necrosis factor alpha (TNFalpha) or 0.1 microM phorbol myristate acetate (PMA). Mevalonate (100 microM), a precursor of isoprenoids, added to cells simultaneously with fluvastatin, suppressed the effect of the drug on PAI-1 both in unstimulated and stimulated cells as well as on t-PA antigen. Among intermediates of the isoprenoid pathway, all-transgeranylgeraniol (5 microM) but not farnesol (10 microM) prevented the effect of 2.5 microM fluvastatin on PAI-1 antigen, which suggests that the former intermediate of the isoprenoid synthesis is responsible for the observed effects.

Temporal trends of stroke in Valle d'Aosta, Italy. Incidence and 30-day fatality rates

The objective of this study was to evaluate temporal changes of stroke in an Italian community by comparing the present incidence rates with those reported in the same area for 1989. The two studies were conducted by the same research group and met almost all the criteria proposed for an "ideal" stroke incidence study. The annual incidence rate per 1000 inhabitants increased (p < 0.01) by 29%, from 2.23 (95% CL, 1.96-2.50) in 1989 to 2.89 (95% CL, 2.58-3.20) in 1997. No statistically significant change was found when these rates were adjusted to the 1991 Italian population. The overall incidence rate was 2.40 (95% CL, 2.14-2.66) in 1989 and 2.65 (95% CL, 2.39-2.91) in 1997. The thirty-day case fatality rate declined dramatically (p < 0.001) from 31% (95% CL, 26-36) to 20% (95% CL, 16-24) between 1989 and 1997. Ageing of the population and better identification of cases could explain the high incidence rate, whereas the decrease of fatality rate may be due to a general improvement in acute care and inclusion of milder cases.

Incidence of xenobiotics among drivers killed in single-vehicle crashes

The authors have performed a study of single-vehicle crashes (SVCs) in order to verify a correlation between the loss of vehicle control and the presence of drugs in the body. Overall, 129 cases were recorded and occurred in the catchment area of the Institute of Legal Medicine in Milan between 1986 to 1996. Among the 129 cases under study, respectively 121 men and eight women, 101 were car-drivers and 28 motor-cyclists. The median age was equal to 29 years, while the average age to 32.0 years (range 15-65 years). Fifty eight cases (45.0%) were "positive" for the presence of ethanol > or = 0.8 g/l or other drugs. The sample of "positive cases" was studied according to sex, age, day, hour and type of vehicle. Considering the cases with presence of ethanol, although under the legal limit (20 cases), the total amount of cases (78) becomes even more consistent. The amount of ethanol was found to be respectively 0.34 g/l in daily drivers and 0.87 g/l in nightly drivers (p < 0.01). Our considerations confirm the importance of toxicological analyses in the forensic investigation of traffic deaths being the sample under study recorded following criteria which minimised other possible factors effecting road accidents.

Blood flow in the internal carotid and middle cerebral arteries: effects of continuous oral conjugated equine estrogens administration with monthly progestogen supplementation on postmenopausal women

OBJECTIVE

This study was designed in order to evaluate the effect of conjugated equine estrogens (CEE) on internal carotid and middle cerebral artery blood flow in postmenopausal women.

DESIGN

Thirty-four healthy postmenopausal women with intact uteri were randomly divided into two groups of 17 subjects each. The first group was treated for 24 weeks with continuous CEE medication (0.625 mg daily) and cyclical supplementations of 5 mg/day of medrogestone acetate, given on the last 12 days of every 4-week period (Prempak, Wyeth, Italy). The second group received no treatment. The pulsatility indices (PI) of both the internal carotid artery and middle cerebral artery were measured.

RESULTS

In the treated group, the PI of the interior carotid artery and MCA was reduced from respectively 0.736 (0.016) and 0.745 (0.009) at baseline, to 0.669 (0.021) and 0.670 (0.011) after 24 weeks (p = 0.01); in the control group, the PI values remained unchanged. The between-group difference for both arteries was significant (p < 0.01).

CONCLUSIONS

The administration of CEE with cyclical medrogestone supplementation to postmenopausal women induces a statistically significant reduction in the PI of cerebral arteries.

Oxidized low density lipoprotein suppresses expression of inducible cyclooxygenase in human macrophages

Atherogenesis involves several aspects of chronic inflammation and wound healing. Indeed, the atheroma is considered a special case of tissue response to injury. Injurious stimuli may include lipoproteins trapped within lesions where protein and lipid moieties have undergone chemical modifications. We have studied the effect of oxidized low density lipoproteins (ox-LDL) on inducible cyclooxygenase (Cox-2) in human monocyte-derived macrophages exposed to bacterial lipopolysaccharide (LPS). Levels of both Cox-2 and constitutive cyclooxygenase (Cox-1) were assessed using Western blot analysis. Prior incubation of macrophages with ox-LDL resulted in a strong inhibition of Cox-2 induced by LPS, without effect on Cox-1. The inhibitory effect was dependent on ox-LDL concentration and its onset was early in time (already detectable 1 hour after macrophage exposure to ox-LDL). Native LDL, and other forms of modified LDL, were without effect. The inhibition was dependent on endocytosis of ox-LDL and could be reproduced using the lipid extract from ox-LDL. Lysophosphatidylcholine, 7beta-hydroxycholesterol, and 7-oxocholesterol failed to mimic the inhibition, but oxidized arachidonic acid-containing phospholipids, produced by autoxidation of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine, markedly inhibited Cox-2. The observation that ox-LDL downregulates Cox-2 in human macrophages may explain the fact that, within atheromata, the transformation of macrophages into foam cells results in attenuation of the inflammatory response, thus contributing to progression of atherogenesis.

The effect of tamoxifen and transdermal 17beta-estradiol on cerebral arterial vessels: a randomized controlled study

OBJECTIVES

Our objective was to study the effects of tamoxifen on cerebral arterial reactivity.

STUDY DESIGN

We studied the reactivity of both the internal carotid artery and the middle cerebral artery during a 12-month period of administration of either oral tamoxifen or transdermal estradiol or no treatment. A total of 45 healthy postmenopausal women who had undergone hysterectomy were followed up. Patients were randomly allocated to treatment with either oral tamoxifen 20 mg/day or transdermal estradiol 50 microg/day or nothing (15 patients in each group). They all underwent Doppler examinations of the internal carotid artery and middle cerebral artery at the beginning of the study and after 2, 6, and 12 months of treatment. The pulsatility index was measured.

RESULTS

In the women given transdermal estradiol the pulsatility index of both the internal carotid artery and the middle cerebral artery was significantly reduced compared with that in the controls. Tamoxifen did not induce variations of pulsatility index in either artery during all the study period. The difference between the effect of the two drugs on the pulsatility index of both arteries was highly significant.

CONCLUSIONS

Our findings demonstrate that tamoxifen does not cause any variation in the pulsatility index of cerebral arteries. The action of transdermal estradiol on the pulsatility index of cerebral arteries in postmenopausal women is the expression of a generalized action of estrogens on arterial vessels, and if this expression plays a role in the protective effect of hormone replacement therapy on risk of cardiovascular disease, tamoxifen treatment in healthy postmenopausal women should be considered with renewed caution.

Cloning of a single-chain variable fragment (scFv) switching active plasminogen activator inhibitor-1 to substrate

Increased levels of plasminogen activator inhibitor-1 (PAI-1) are a well-known risk for cardiovascular diseases. A significant number of investigations are aimed at lowering plasma levels of PAI-1 to enhance endogenous fibrinolysis. We have recently generated monoclonal antibodies that neutralize PAI-1 activity by switching the inhibitory conformation to a substrate conformation. However, intact murine antibodies have quite some disadvantages for therapeutic use in man. In the current study, we describe the construction of a smaller antibody fragment derived from a monoclonal antibody (MA-8H9D4) with PAI-1 neutralizing properties. The cDNAs encoding the variable domains of the heavy and light chain were amplified, linked and cloned into a phagemid vector. Resulting clones were expressed as a single-chain variable fragment (scFv, VH-(Gly4Ser)3-VL) on the surface of a phage and selected for binding to PAI-1. Subsequently, a positive phage was used for the production of soluble scFv-8H9D4. Following purification, the characteristics of the scFv-8H9D4 were compared to those of the original MA-8H9D4. The scFv inhibited PAI-1 activity to a similar extent as MA-8H9D4 and by a similar mechanism, i.e., induction of a conformational switch. Thus, this smaller antibody fragment, exhibiting the same properties as the parent molecule may constitute a useful starting point for the design of PAI-1 neutralizing therapeutics.

Cerebral artery blood flow in relation to age and menopausal status

OBJECTIVE

To investigate vascular reactivity in women's cerebral arteries from reproductive age to postmenopause.

METHODS

The pulsatility index (PI) was measured cross-sectionally in the internal carotid and middle cerebral arteries of 120 women, using a Doppler ultrasound system. Fifteen women were enrolled in each of eight 5-year intervals, spanning ages 20-59 years.

RESULTS

In the population as a whole, there was a slight but statistically significant correlation between age and the PI in both arteries, but not after excluding postmenopausal subjects. A significant correlation was found between PI and months since menopause (but not chronologic age) in the postmenopausal women. There was also a statistically significant difference in the PI values for both arteries between pre- and postmenopausal women of similar age.

CONCLUSION

Menopause causes a significant increase in the PI of women's cerebral arteries. In postmenopausal women, there is a significant correlation between the PI of the internal carotid and middle cerebral arteries and menopausal but not chronologic age. This effect may be one of the mechanisms by which menopause is associated with the known higher risk for coronary heart disease observed in women.

Plasminogen activator inhibitor type-1 synthesis and mRNA expression in HepG2 cells are regulated by VLDL

The effect of VLDL on plasminogen activator inhibitor type 1 biosynthesis in HepG2 cells was investigated. Exposure of HepG2 cells to VLDL (range, 10 to 100 micrograms protein per milliliter) for 16 hours resulted in an enhanced release of PAI-1 antigen and PAI activity into conditioned medium, accompanied by the accumulation of intracellular triglycerides. By using a monoclonal antibody (IgG C7) specific to the LDL receptor, we showed that the effect of VLDL is mediated by its interaction with the LDL receptor. Enhanced PAI-1 release was due to increased biosynthesis: PAI-1 mRNA was doubled, mainly because of the effect on the 2.2-kb PAI-1 mRNA rather than the 3.2-kb transcript. Addition of insulin with the VLDL further enhanced PAI-1 antigen release and PAI-1 mRNA accumulation. The effect of VLDL on steady state levels of PAI-1 mRNA was apparently not due to an increase of gene transcription but to stabilization of both PAI-1 mRNA transcripts. The enhancing effect of VLDL on PAI-1 biosynthesis in HepG2 cells may raise PAI-1 antigen levels not only in hypertriglyceridemic states but also in those conditions in which both insulin and VLDL are elevated.

Complete testicular feminization with normal gonadotropin and high androgen secretion: a case report

A patient with a complete form of testicular feminization with normal gonadotropin and high testosterone levels is described here. These findings are in contrast to previous reports that have shown high circulating luteinizing hormone (LH) levels in adults affected by this syndrome. Testicular histology revealed tubular atrophy and hyperplastic Leydig cells which are in accordance with the high testosterone levels and the difficulty in visualization of the testes. Because of the increased risk of gonadal malignancy, a laparoscopic gonadectomy was performed.

Organ-specific autoimmunity in patients with premature ovarian failure

The diagnosis of premature ovarian failure (POF) was made in 45 women (aged 14 to 39 yr) with high concentrations of FSH and LH. Sera from these patients and a control group of 28 women were used to detect organ-specific autoantibodies. Eighteen patients with POF (40%) were positive for at least one autoantibody. In the control group only one woman (3.6%) showed autoimmunity. Antithyroid was the most representative autoimmunity (20%) in the POF group. By indirect immunofluorescence, only one patient was positive for antiovarian and antiadrenal antibodies. In summary, the results of this study are consistent with previous immunohistochemical data which indicate that autoimmune disorders are common in patients with POF. Furthermore, the detection of antiovarian antibodies in only one patient confirms that they are probably detectable in a short period of the disease.

Increased synthesis of plasminogen activator inhibitor-1 by cultured human endothelial cells exposed to native and modified LDLs. An LDL receptor-independent phenomenon

The effects of native and acetylated low density lipoproteins (LDLs and acetyl-LDLs, respectively) on the release of plasminogen activator inhibitor type 1 (PAI-1) by cultured human umbilical vein endothelial cells (ECs) were evaluated. LDL and acetyl-LDL incubated with ECs for 16-18 hours increased the PAI-1 antigen levels in conditioned medium. At a concentration of 100 micrograms/mL, LDL and acetyl-LDL increased PAI-1 by 10.8 and 12.0 ng/mL, respectively (p < 0.05 and p < 0.01 versus control). The increases in PAI-1 antigen levels exerted by the lipoproteins paralleled the changes in PAI-1 activity. The effect of LDL and acetyl-LDL was concentration dependent and specific for PAI-1 because tissue-type plasminogen activator and expression of procoagulant activity were not affected by either lipoprotein. In addition, total protein synthesis evaluated in [35S] methionine-labeled ECs was not affected, and studies with cycloheximide showed that the effect of LDL and acetyl-LDL on PAI-1 release was due to de novo protein synthesis. Experiments using the C7 monoclonal antibody against the LDL receptor and binding-defective LDL indicated that the effect of LDL on the synthesis of PAI-1 was not dependent on the interaction of the LDLs with their specific receptors. Finally, extensive oxidation of LDL prevented and even reversed the effect of LDL on PAI-1 release by ECs. It is concluded that LDL specifically increases the synthesis of PAI-1 by ECs with mechanisms that are not receptor mediated.

Hypertriglyceridemia and regulation of fibrinolytic activity

A relation between elevated triglyceride (TG) levels and alterations of the fibrinolytic system has been recognized in studies of patients with coronary heart disease. In this investigation, the total fibrinolytic activity and the levels of specific components of the fibrinolytic system were evaluated in plasma samples from a highly selected group of patients with type IV hyperlipoproteinemia before and after a dietary treatment aimed at reducing TG levels. The fibrinolytic response of type IV patients was comparable to that of normolipidemic subjects, whereas tissue-type plasminogen activator antigen levels before and after venous occlusion (p less than 0.01) and resting plasminogen activator inhibitor-1 (PAI-1) antigen (p less than 0.01) and activity (p less than 0.01) were significantly higher in hypertriglyceridemic subjects compared with controls. After dietary treatment, a 22% reduction in TG levels was attained in type IV patients, with no appreciable modification of fibrinolytic parameters. The analysis of the single-patient data revealed a tendency toward normalization of PAI-1 levels only in those patients who showed a TG reduction greater than or equal to 20%. Very low density lipoproteins (VLDLs) from both normal and type IV patients concentration-dependently stimulated PAI-1 release by endothelial cells and HepG2 cells, with the effect of VLDL from type IV patients being more pronounced on HepG2 cells. The release of PAI-1 induced by VLDL in competent cells may thus account for the elevated levels of this antifibrinolytic protein that occur in hypertriglyceridemic patients.

Frequency of multiple sclerosis in Valle d'Aosta, 1971-1985

According to studies done before 1980, the multiple sclerosis (MS) prevalence rate in Italy ranged from 7.2 to 27.1 cases per 100,000 inhabitants. More recent work has consistently put the MS prevalence rate to over 30 cases per 100,000 inhabitants. If these recent data are confirmed in the future, Italy can no longer be regarded as a country at low risk for MS, but must be included among the medium-high risk countries of continental Europe. We report the results of a prevalence and incidence survey conducted in Valle d'Aosta, a region whose special features make it an excellent epidemiological model. The mean annual incidence was 2.1 and on December 31, 1985, the prevalence was 39 cases per 100,000 inhabitants. These results confirm that the incidence and prevalence rate of MS in Valle d'Aosta is close to that of areas at high-risk for MS.

Treatment of radiolucent gallstones with CDCA or UDCA. A multicenter trial

Patients with radiolucent gallstones (diameter less than 1.5 cm) and functioning gallbladder were treated for 6-12 months with CDCA (38 patients, 12-15 mg/kg/day) or UDCA (78 patients randomly allocated to receive 5-6 or 10-12 mg/kg/day). Complete dissolutions and partial plus complete dissolutions were respectively 26 and 58% for CDCA, 14 and 58% for UDCA at the lower dose, and 29 and 71% for UDCA at the higher dose. Statistical analysis did not show any significant difference between the three different treatments. In patients with stones of 4-10 mm diameter treated with UDCA, complete dissolution occurred at the lower dose in 0 of 14 cases while complete dissolutions occurred at the higher dose in 5 of 18 cases, suggesting that the latter dose may be more effective (0.05 less than P less than 0.1). A highly significant correlation was demonstrated between gallstone size and number of dissolutions with both doses of UDCA. No side effects were observed with UDCA, while with CDCA diarrhea occurred in 28% and a transient increase in SGOT in a single patient. 1 patient on UDCA required emergency cholecystectomy for acute cholecystitis. Dyspeptic and/or pain symptom-atology improved in 65 and 85% of the patients treated with CDCA and UDCA, respectively. No variations in the blood lipids were observed.

Radiolucent gallstone dissolution with bedtime UDCA administration

26 patients (20 females and 6 males, mean age 40.5 years +/- SEM 2.20, mean weight 60.2 kg +/- 1.98) with radiolucent gallstones of diameter less than or equal to 10 mm were treated for 6 months with ursodeoxycholic acid (UDCA), a single dose of 600 mg at bedtime. The rate of partial + complete dissolutions was 85%, reaching 100% for gallstones of less than 4 mm diameter. No side effects were observed. In a similar series of patients treated with UDCA t.i.d. at mealtimes (10--12 mg/kg/day) a slightly lower dissolution rate was obtained but the difference was not statistically significant.