Preliminary Results of External Sapheno–Femoral Valvuloplasty: A Trial by the Italian Society of Phlebolymphology

A multicentric trial was conducted to compare the various methods, materials and results employed in external valvuloplasty of the sapheno-femoral junction. Dacron, PTFE and absorbable prostheses have been used and have lead to the following conclusions: careful diagnosis and selection of patients is necessary; dilatation of both terminal and sub-terminal saphenous valves should be treated; at present, PTFE seems the best material to use (follow-up for the absorbable material is too short); the operation is effective and can be recommended in selected cases.

Considerations of the Anatomical Variations in the Venous System of the Lower Limbs in Varicose Disease

The Authors experience in the surgical treatment of varicose veins of the lower limbs in the last 15 years, performed on 1500 cases, show that varicose recurrence may be nearly always attributed to unrecognised anatomical variations in the venous system. Methods of preoperative and intraoperative diagnosis are described and the most frequent variants observed are presented and their significance are discussed.

Regulation of FADS2 expression and activity in European sea bass (Dicentrarchus labrax, L.) fed a vegetable diet

Supplies of marine fish oils are limited, and continued growth in aquaculture production dictates that lipid substitutes in fish diets must be used without compromising fish health and product quality. In this study, the total substitution of a fish meal and fish oil by a blend of vegetable meals (corn, soybean, wheat and lupin) and linseed oil in the diet of European sea bass (Dicentrachus labrax) was investigated. Two groups of European sea bass were fed with fish diet (FD) or vegetable diet (VD) for 9months. VD, totally deprived of eicosapentaenoate (EPA; 20:5n-3) and docosahexaenoate (DHA; 22:6n-3), revealed a nutritional deficiency and affected growth performance. Whilst VD induced a significant increase in fatty acid desaturase 2 (FADS2) and sterol binding regulatory element-binding protein 1 (SREBP-1) mRNA levels, the desaturation rate of [1-(14)C]18:3n-3 into [1-(14)C]18:4n-3, analysed in microsomal preparations using HPLC method, did not show an upregulation of FADS2 activities in liver and intestine of fish fed VD. Moreover Western-blot analysis did not revealed any significant difference of FADS2 protein amount between the two dietary groups. These data demonstrate that sea bass exhibits a desaturase (FADS2) activity whatever their diet, but a post-transcriptional regulation of fads2 RNA prevents an increase of enzyme in fish fed a HUFA-free diet. This led to a lower fish growth and poor muscle HUFA content.

[Is there still a place for the correction of chronic venous insufficiency of the lower limbs by valvuloplasty]

AIM

Various surgical procedures, extravenous (VPE) AND intravenous (VPI) valvuloplasties were described for the treatment of superficial (IVCS) and deep (IVCP) chronic venous insufficiency.

METHODS

In 18 years: 153 VPE in limbs affected with IVCS. 9 VPE, 26 VPI (10 typical, 8 atypical, 8 autologous) and 38 other procedures in 74 limbs with IVCP selected and controlled by US (hemodynamic improvement or normalization = MNE) and X-ray (5 VPI).

RESULTS

IVCS: 153 VPE=8,2% of the general casuistry. ;: MNE) 90,2% ( mean follow-up. 5 y,4 m.); stable at 10 y 68%; best results in IVCS <20 y. (Chi-sq.P=0.05). IVCP: VPE=12,3% and VPI=35,6% of the interventions; 9 VPE: MNE 88,8%; 26 VPI: MNE 81,4%; hemodynamic normalization by VPE-VPI(n.7/27=25,9%) (mean follow-up.7 y.,8 m.).

CONCLUSIONS

VPE: Indicated in selected cases with IVCS and IVCP. In IVCP VPE-VPI are preferable than other procedures. Atypical and autologous VPI represents a technical progress in valveless syndromes.

Comparison of the cytotoxic, pro-oxidant and pro-inflammatory characteristics of different oxysterols

Oxidized low-density lipoproteins play important roles in the development of atherosclerosis and contain several lipid-derived, bioactive molecules which are believed to contribute to atherogenesis. Of these, some cholesterol oxidation products, referred to as oxysterols, are suspected to favor the formation of atherosclerotic plaques involving cytotoxic, pro-oxidant and pro-inflammatory processes. Ten commonly occurring oxysterols (7alpha-, 7beta-hydroxycholesterol, 7-ketocholesterol, 19-hydroxycholesterol, cholesterol-5alpha,6alpha-epoxide, cholesterol-5beta,6beta-epoxide, 22R-, 22S-, 25-, and 27-hydroxycholesterol) were studied for both their cytotoxicity and their ability to induce superoxide anion production (O2*-) and IL-8 secretion in U937 human promonocytic leukemia cells. Cytotoxic effects (phosphatidylserine externalization, loss of mitochondrial potential, increased permeability to propidium iodide, and occurrence of cells with swollen, fragmented and/or condensed nuclei) were only identified with 7beta-hydroxycholesterol, 7-ketocholesterol and cholesterol-5beta,6beta-epoxide, which also induce lysosomal destabilization associated or not associated with the formation of monodansylcadaverine-positive cytoplasmic structures. No relationship between oxysterol-induced cytotoxicity and HMG-CoA reductase activity was found. In addition, the highest O2*- overproduction quantified with hydroethidine was identified with 7beta-hydroxycholesterol, 7-ketocholesterol and cholesterol-5beta,6beta-epoxide, with cholesterol-5alpha, 6alpha-epoxide and 25-hydroxycholesterol. The highest capacity to simultaneously stimulate IL-8 secretion (quantified by ELISA and by using a multiplexed, particle-based flow cytometric assay) and enhance IL-8 mRNA levels (determined by RT-PCR) was observed with 7beta-hydroxycholesterol and 25-hydroxycholesterol. None of the effects observed for the oxysterols were detected for cholesterol. Therefore, oxysterols may have cytotoxic, oxidative, and/or inflammatory effects, or none whatsoever.

Caspase-2, a novel lipid sensor under the control of sterol regulatory element binding protein 2

Caspases play important roles in apoptotic cell death and in some other functions, such as cytokine maturation, inflammation, or differentiation. We show here that the 5'-flanking region of the human CASP-2 gene contains three functional response elements for sterol regulatory element binding proteins (SREBPs), proteins that mediate the transcriptional activation of genes involved in cholesterol, triacylglycerol, and fatty acid synthesis. Exposure of several human cell lines to statins, lipid-lowering drugs that drive SREBP proteolytic activation, induced the CASP-2 gene to an extent similar to that for known targets of SREBP proteins. Adenoviral vector-mediated transfer of active SREBP-2 also induced expression of the CASP-2 gene and the caspase-2 protein and increased the cholesterol and triacylglycerol cellular content. These rises in lipids were strongly impaired following small interfering RNA-mediated silencing of the CASP-2 gene. Taken together, our results identify the human CASP-2 gene as a member of the SREBP-responsive gene battery that senses lipid levels in cells and raise the possibility that caspase-2 participates in the control of cholesterol and triacylglycerol levels.

Identification of a functional DNA binding site for the SREBP-1c transcription factor in the first intron of the human caspase-2 gene

Sterol Regulatory Element Binding Proteins (SREBP) are transcription factors that regulate lipid synthesis. We have shown recently that the human CASP-2 gene, encoding procaspase-2, was under the positive control of SREBP-2 that transactivates several responsive elements in the promoter region. We describe here the function of an additional SREBP-responsive element located in the first intron. Remarkably, this site is uniquely responsive to SREBP-1c that is mainly involved in fatty acids synthesis. This observation, together with our recent findings, strengthens the notion that the CASP-2 gene belongs to the SREBP-responsive gene battery in human cells.

A new autologous venous valve by intimal flap. One case report

Various surgical techniques have been proposed for the treatment of chronic venous insufficiency of post-thrombotic recanalized deep veins of the lower limbs. The preferable method seems to be represented by intravenous valvuloplasty except for the cases affected by extensive valvular damage. For this reason some experimental autologous, heterologous and prosthetic venous valves have been proposed. Such a problem emerged for 1 patient (male, aged 78 years, right limb, leg dystrophy, multiple ulcerations at the ankle) which was selected by duplex, Doppler venous pressure index, photoplethysmography and ascending phlebography. An iliac-femoral and popliteal post-thrombotic, recanalized, decompensated venous insufficiency and one Cockett's perforator incompetence were diagnosed (CEAP classification: C6s Es As2d14 Pr). A bicuspid apparently repairable popliteal valve was detected by phlebography. A traditional intravenous valvuloplasty was planned but the valve was not found at surgical exploration. A monocuspid valve reconstruction by intimal flap vein was performed. The following results were obtained and controlled after one year: stable ulceration healing, dystrophy reduction, improvement in the quality of life, normalization of the hemodynamic parameters and of the radiological morphology of the new valve. It can be concluded that monocuspid valvular repair by intimal flap can be successfully performed in cases affected by secondary valveless deep venous insufficiency of the lower limbs.

Early increase in DcR2 expression and late activation of caspases in the platelet storage lesion

Platelet transfusion is widely used to prevent bleeding in patients with severe thrombocytopenia. The maximal storage duration of platelet concentrates is usually 5 days, due to the platelet storage lesion that impairs their functions when stored for longer times. Some of the morphological and biochemical changes that characterize this storage lesion are reminiscent of cell death by apoptosis. The present study analyzed whether proteins involved in nucleated cell apoptosis could play a role in the platelet storage lesion. Storage of leukocyte-depleted platelets obtained by apheresis is associated with a late and limited activation of caspases, mainly caspase-3. This event correlates with an increased expression of the pro-apoptotic BH3-only protein Bim in the particulate fraction and a slight and late release of the pro-apoptotic mitochondrial protein Diablo/Smac in the cytosol. Platelets do not express the death receptors Fas, DR4 and DR5 on their plasma membrane, while the expression of the decoy receptor DcR2 increases progressively during platelet storage. Addition of low concentrations of the cryoprotector dimethylsulfoxide accelerates platelet caspase activation during storage, an effect that is partially prevented by the caspase inhibitor z-VAD-fmk. Altogether, DcR2 expression on the plasma membrane is an early event while caspase activation is a late event during platelet storage. These observations suggest that caspases are unlikely to account for the platelet storage lesion. As a consequence, addition of caspase inhibitors may not improve the quality of platelet concentrates stored in standard conditions.

Modulation of apoptotic pathways triggered by cytotoxic agents

Anticancer drugs can induce tumour cell death by apoptosis. The main pathway from specific damage induced by the drug to apoptosis involves activation of caspases in the cytosol by pro-apoptotic molecules such as cytochrome c released from the mitochondria. At least in some cell types, anticancer drugs also upregulate the expression of death receptors and sensitize tumour cells to their cognate ligands, which could be used to amplify the response to cytotoxic drugs. The Bcl-2 family of proteins, which includes anti- and pro-apoptotic molecules, regulates cell sensitivity at the mitochondrial level. Chemotherapeutic drugs modulate their expression (e.g. through p53-dependent gene transcription), their activity (e.g. by phosphorylation) and their subcellular localization (e.g. by translocation of pro-apoptotic proteins from the cytosol to the mitochondria). When interacting with tumour cells, anticancer drugs also activate lipid- and kinase-dependent signalling pathways that modulate the death response to specific damage. Protective pathways include activation of NF kappa B transcription factor, accumulation of heat shock proteins and activation of proteins involved in cell cycle regulation. The recent identification on these pathways to cell death has suggested several new strategies to improve the therapeutic efficacy of currently used anticancer drug regimens.

Gene induction by Phenobarbital: an update on an old question that receives key novel answers

Phenobarbital has long been used as a sedative and antiepileptic drug. The drug is the representative of a myriad of lipophilic molecules able to evoke a pleiotropic response in the liver and also in prokaryotes and flies. A great deal of novel information has been obtained in recent years regarding the mechanism of cytochrome P450 (CYP) gene induction by phenobarbital. Most importantly, a nuclear orphan receptor, the constitutive androstane receptor has been identified as a primary determinant of the transcriptional activation of CYP genes in response to phenobarbital-like inducers in mammals. Another nuclear receptor, the pregnane X receptor can also mediate some of the phenobarbital response, but the functional overlap of the two inductive pathways is only partial. The response of mammalian CYP2B genes to phenobarbital was abolished in the liver of mice carrying a null allele of the constitutive androstane receptor gene, whereas that of CYP3A genes was lost in pregnane X receptor knock-out mice.

Mitochondria-targeting drugs arsenic trioxide and lonidamine bypass the resistance of TPA-differentiated leukemic cells to apoptosis

Exposure of U937 human leukemic cells to the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) induces their differentiation into monocyte/macrophage-like cells. This terminal differentiation is associated with a resistant phenotype to apoptosis induced by the topoisomerase II inhibitor etoposide. The inhibition occurs upstream of the mitochondrial release of cytochrome c and the activation of procaspase-2, -3, -6, -7, -8, and -9. By using cell-free systems, it was demonstrated that the mitochondrial pathway to cell death that involves mitochondrial membrane depolarization, cytochrome c release and cytosolic activation of procaspases by cytochrome c/dATP remains functional in TPA-differentiated U937 cells. Accordingly, 2 drugs recently shown to target the mitochondria, namely lonidamine and arsenic trioxide, bypass the resistance of TPA-differentiated U937 cells to classical anticancer drugs. Cell death induced by the 2 compounds is associated with mitochondrial membrane depolarization, release of cytochrome c and Smac/Diablo from the mitochondria, activation of caspases, poly(ADP-ribose) polymerase cleavage and internucleosomal DNA fragmentation. Moreover, the decreased glutathione content associated with the differentiation process amplifies the ability of arsenic trioxide to activate the mitochondrial pathway to cell death. Similar results were obtained by comparing undifferentiated and TPA-differentiated human HL60 leukemic cells. These data demonstrate that mitochondria-targeting agents bypass the resistance to classical anticancer drugs induced by TPA-mediated leukemic cell differentiation. (Blood. 2001;97:3931-3940)

Regulation of phenobarbital-induction of CYP2B and CYP3A genes in rat cultured hepatocytes: involvement of several serine/threonine protein kinases and phosphatases

We investigated the involvement of diverse protein kinases and phosphatases in the transduction pathways elicited by phenobarbital (PB), a well-known inducer of some hepatic cytochromes P450 (CYP). Different inhibitors or activators of protein kinases or phosphatases were assessed for their ability to modulate PB-induction of CYP2B and CYP3A mRNA expression. Rat hepatocytes in primary culture were treated with the test compounds one hour prior to, and then continuously, in the absence or presence of 1 mmol/L PB for 24 h. By northern blot analysis of CYP2B1/2 and 3A1/2 gene expression, we first confirmed the negative role of the adenosine 3':5' cyclic monophosphate (cAMP)/protein kinase A pathway and the positive role of some serine/threonine protein phosphatases in the mechanism of PB-induction. The present data further suggested that Ca2+/calmodulin-dependent protein kinases II (independently of Ca2+) and extracellular signal-regulated kinases 1/2 (ERK1/2) might function respectively as positive and negative regulator in the PB-induction of CYP2B and CYP3A. In contrast, protein kinases C and phosphatidylinositol-3-kinase did not appear to be involved, while the role of tyrosine kinases remained unclear. We conclude that a complex network of phosphorylation/dephosphorylation events might be crucial for PB-induction of rat CYP2B and CYP3A.

The induction of the human hepatic CYP2E1 gene by interleukin 4 is transcriptional and regulated by protein kinase C

Cytochrome P4502E1 (CYP2E1) plays a key role in the metabolism of numerous drug substrates, mostly in mammalian liver. Both the apoprotein and mRNA levels are increased in response to interleukin 4 (IL-4) in primary human hepatocyte cultures. We developed a human hepatoma cell model that faithfully reproduces the responsiveness of the CYP2E1 gene to IL-4 at least in part through transcriptional activation, upon treatment with 150 U/ml of IL-4. As expected, IL-4 induced tyrosine phosphorylation of the STAT6 transcription factor, an effect prevented by the tyrosine kinase inhibitor tyrphostin A25. However, this inhibitor as well as genistein (another inhibitor of tyrosine kinases) had no effect on the IL-4 induction of CYP2E1. Similarly, protein kinase A activators (forskolin and dibutyryl-cAMP) and inhibitor (H89) did not influence the response to IL-4. However, PKC inhibitors (H7 and calphostin C) strongly blocked any induction of the gene, as well as the IL-4-dependent translocation of PKCS. Taken together, our results show that IL-4 coordinately induces CYP2E1 transcription, mRNA and apoprotein levels in human hepatoma cells in a PKC-dependent manner, potentially through the activity of the PKCzeta isoform.

Carbamazepine: a 'blind' assessment of CVP-associated metabolism and interactions in human liver-derived in vitro systems

1. The ability of various in vitro systems for CYP enzymes (computer modelling, human liver microsomes, precision-cut liver slices, hepatocytes in culture, recombinant enzymes) to predict various aspects of in vivo metabolism and kinetics of carbamazepine (CBZ) was investigated. 2. The study was part of the EUROCYP project that aimed to evaluate relevant human in vitro systems to study drug metabolism. 3. CBZ was given to the participating laboratories without disclosing its chemical nature. 4. The most important enzyme (CYP3A4) and metabolic route (10,11-epoxidation) were predicted by all the systems studied. 5. Minor enzymes and routes were predicted to a different extent by various systems. 6. Prediction of a clearance class, i.e. slow clearance, was correctly predicted by microsomes, slices, hepatocytes and recombinant enzymes (CYP3A4). 7. The 10,11-epoxidation of CBZ by the recombinant CYP3A4 was enhanced by the addition of exogenous cytochrome-b5, leading to a considerable over-prediction. 8. Induction potency of CBZ was predicted in cultured hepatocytes in which 7-ethoxycoumarin O-deethylase was used as an index activity. 9. It seems that for a principally CYP-metabolized substance such as CBZ, all liver-derived systems provide useful information for prediction of metabolic routes, rates and interactions.

An assessment of human liver-derived in vitro systems to predict the in vivo metabolism and clearance of almokalant

The ability of various human derived in vitro systems to predict various aspects of the in vivo metabolism and kinetics of almokalant have been investigated in a multicenter collaborative study. Although almokalant has been withdrawn from further clinical development, its metabolic and pharmacokinetic properties have been well characterized. Studies with precision-cut liver slices, primary hepatocyte cultures, and hepatic microsomal fractions fortified with UDP-glucuronic acid all suggested that almokalant is mainly glucuronidated to the stereoisomers M18a and M18b, which is in good agreement with the results in vivo. Both in vivo and in vitro studies indicate that the formation of M18b dominates over that of M18a, although the difference is more pronounced with the in vitro systems. Molecular modeling, cDNA-expressed enzyme analysis, correlation analysis, and inhibition studies did not clearly indicate which P450 enzymes catalyze the oxidative pathways, which may indicate a problem in identifying responsible enzymes for minor metabolic routes by in vitro methods. All of the in vitro systems underpredicted the metabolic clearance of almokalant, which has previously been reported to be a general problem for drugs that are cleared by P450-dependent metabolism. Although few studies on in vivo prediction of primarily glucuronidated drugs have appeared, in vitro models may consistently underpredict in vivo metabolic clearance. We conclude that in vitro systems, which monitor phase II metabolism, would be beneficial for prediction of the in vivo metabolism, although all of the candidate liver-derived systems studied here, within their intrinsic limitations, provided useful information for predicting metabolic routes and rates.

Anticancer agents sensitize tumor cells to tumor necrosis factor-related apoptosis-inducing ligand-mediated caspase-8 activation and apoptosis

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a new cytokine that was proposed to specifically induce apoptosis of cancer cells. In tumor cells that are resistant to the cytokine, subtoxic concentrations of chemotherapeutic drugs can restore the response to TRAIL. The present study further explores the mechanisms that determine tumor cell sensitivity to TRAIL by comparing four human colon carcinoma cell lines We show that colon cancer cell sensitivity to TRAIL-induced apoptosis and cytotoxicity correlates with the expression of the death receptors TRAIL-R1 and TRAIL-R2 at the cell surface, as determined by now cytometry, whereas the two decoy receptors TRAIL-R3 and TRAIL-R4 can be detected only in permeabilized cells. Clinically relevant concentrations of cisplatin and doxorubicin sensitize the most resistant colon cancer cell lines to TRAIL-induced cell death without modifying the expression nor the localization of TRAIL receptors in these cells. TRAIL induces the activation of procaspase-8 and triggers caspase-dependent apoptosis off colon cancer cells. Cytotoxic drugs lower the signaling threshold required for TRAIL-induced procaspase-8 activation. In turn, caspase-8 cleaves Bid, a BH3 domain-containing proapoptotic molecule of the Bcl-2 family and activates effector caspases. Together, these data indicate that chemotherapeutic drugs sensitize colon tumor cells to TRAIL-mediated caspase-8 activation and apoptosis.

Positive and negative regulation of apoptotic pathways by cytotoxic agents in hematological malignancies

Most chemotherapeutic drugs can induce tumor cell death by apoptosis. Analysis of the molecular mechanisms that regulate apoptosis has indicated that anticancer agents simultaneously activate several pathways that either positively or negatively regulate the death process. The main pathway from specific damage induced by the drug to apoptosis involves activation of caspases in the cytosol by pro-apoptotic molecules such as cytochrome c released from the mitochondrial intermembrane space. At least in some cell types, anticancer drugs also upregulate the expression of death receptors and sensitize tumor cells to their cognate ligands. The Fas-mediated pathway could contribute to the early steps of drug-induced apoptosis while sensitization to the cytokine TRAIL could be used to amplify the response to cytotoxic drugs. The Bcl-2 family of proteins, that includes anti- and pro-apoptotic molecules, regulates cell sensitivity mainly at the mitochondrial level. Anticancer drugs modulate their expression (eg through p53-dependent gene transcription), their activity (eg by phosphorylating Bcl-2) and their subcellular localization (eg by inducing the translocation of specific BH3-only pro-apoptotic proteins). Very early after interacting with tumor cells, anticancer drugs also activate lipid-dependent signaling pathways that either increase or decrease cell ability to die by apoptosis. In addition, cytotoxic agents can activate protective pathways that involve activation of NFkappaB transcription factor, accumulation of heat shock proteins such as Hsp27 and activation of proteins involved in cell cycle regulation. This review discusses how modulation of the balance between noxious and protective signals that regulate drug-induced apoptosis could be used to improve the efficacy of current therapeutic regimens in hematological malignancies.

Phenobarbital induction of aldehyde dehydrogenase type 2 mRNA in mouse liver: a candidate region on chromosome 7 for a putative regulatory gene

Phenobarbital (PB) strongly induces in the liver the expression of many genes encoding detoxication enzymes, such as the aldehyde dehydrogenase type 2 in the mouse (Aldh2). With the aim of identifying genes involved in this response, we have undertaken an approach based on a genetic analysis in mice. In a previous report, the genetic analysis of both the C57BL/6J (B6) x DBA/2J (D2) F1 and the (F1 x F1) F2 led us to the hypothesis that Aldh2 responsiveness to PB was under the control of one major locus independent of the structural gene. In the present study, the genetic analysis of the inducibility by PB of Aldh2 in the backcross population B6D2F1 x D2 has allowed us to confirm the involvement of a major regulatory gene in this mechanism. By searching for genetic linkage between this locus and a series of microsatellites DNA markers, we obtained indicative evidence for a region on chromosome 7, which may carry this gene.

Inhalation of toluene diisocyanate affects cytochrome P450 2B1 expression in rat lung

In the lung the expression of xenobiotic-metabolizing enzymes such as cytochromes P450 (CYP) and glutathione S-transferases (GST) may be affected by inhaled pollutants. Toluene diisocyanate (TDI) is a highly volatile chemical compound known to induce a wide array of diseases in workers exposed to vapors or sprays, including respiratory allergy and asthma. We investigated the effect of inhaled TDI on expression of CYP 1A1, 2B1, 2E1, and 3A1 and of alpha-, mu-, and pi-GST in rat lung. Animals were exposed to targeted concentrations of 0.01, 0.1, or 1 ppm TDI vapors or to cleaned filtered air for 8 h. Expression of CYP and GST was analyzed 18 24 h after the end of exposure using western blotting, northern blotting, and immunohistochemistry. Constitutive levels of CYP 2B1 and 3A1 proteins were found in lung tissue from control rats, whereas CYP 1A1 and 2E1 proteins were not detectable. Animal exposure to TDI vapors neither modified CYP 3A1 protein expression, nor led to any detectable expression of CYP 1A1 or 2E1. In contrast, exposure to 1 ppm TDI induced a 40% reduction in CYP 2B1 protein levels. This decrease was associated with a 33% decrease in CYP 2B1 mRNA levels. Additionally, CYP 2B1 immunolabeling localized to ciliated epithelial cells, Clara cells, and type II alveolar cells in the lung tissue of control rats was markedly decreased in animals exposed to 1 ppm TDI. Constitutive levels of alpha-, mu-, and pi-GST proteins were found in lung tissue from control rats. Exposure to TDI had no effect on lung expression of either of the GST. In conclusion, this study clearly shows a selective decrease in CYP 2B1 expression by TDI vapors in rat lung. The contribution of CYP 2B1 to metabolize further xenobiotics is therefore altered.

Proximal long saphenous vein valves in primary venous insufficiency

OBJECTIVE

To verify some of the previous findings of venous valves described in the literature, their pathophysiological significance and clinical implications.

MATERIALS AND METHODS

The elementary components of 65 proximal valves of the long saphenous vein and their interrelationships were subjected to histopathological examination. Valves were taken from patients subjected to long saphenous vein surgical removal for varicose veins of the lower limbs. Measurements and morphological evaluations were performed by optical microscopy.

RESULTS

The valvular sinus, agger and proximal portion of the cusp underwent parallel variations of thickness. Thickening of the proximal portion of cusp was related to increase in smooth muscle cells in the agger and to elastic layer dissociation. Thickening of the distal portion of cusp depended on the collagen component; sometimes it was shortened, crumpled and led to the formation of a thickened border. The vein wall in a commissural aneurysm was usually thinner than in the valvular sinus. Alterations in the intima, in the elastic membrane and in the media were found in the 98% of the valvular annulus. Ectasis and asymmetry of the venous wall were mainly related to the muscular hypoplasia of the media.

CONCLUSIONS

The development of primary venous insufficiency seems to be due to the following tissue alterations: dilatation of the valvular annulus and hypotrophy of the cusp. The hemodynamic mechanical injury increases the tissue damages of both annulus and cusps. This pathophysiologic interpretation of venous insufficiency suggests the need for detailed diagnostic procedures before reparative surgery of valves.

Regulation of phenobarbital induction of the cytochrome P450 2b9/10 genes in primary mouse hepatocyte culture. Involvement of calcium- and cAMP-dependent pathways

Phenobarbital (PB) has long been known as an inducer of drug-metabolizing enzymes in liver, but the molecular mechanism underlying this induction is still poorly understood. Using primary mouse hepatocyte culture, we have investigated the possible involvement of different regulatory pathways in PB action, by exposing PB-treated cells to various protein kinase/phosphatase modulators. Our results showed a negative role of the cAMP-dependent pathway, as treatment with cAMP-dependent protein kinase (PKA) activators (10 microM dibutyryl-cAMP and 50 microM forskolin) dramatically inhibited PB-induced Cyp2b9/10 mRNA accumulation, whereas PKA inhibitor potentiated the PB responsiveness of this gene. The cGMP-dependent protein kinase (PKG) seems to play a positive role as PKG inhibitor reduced the PB-induced level of Cyp2b9/10 mRNA. We also obtained two lines of evidence for the involvement of Ca2+ in modulating PB action. Firstly, measurements of intracellular Fura-2 fluorescence ratio in murine hepatocytes showed that long-term PB incubation (24 and 48 h) led to a significant increase of [Ca2+]i. Secondly, treatment with an intracellular Ca2+ chelator (BAPTA-AM) nearly completely abolished PB-induced Cyp2b9/10 expression. Ca2+ thus appeared to mediate PB action likely via Ca2+/calmodulin-dependent protein kinase II, as KN62, a specific inhibitor of this enzyme, also dramatically inhibited PB induction of the Cyp2b9/10 genes.

Detoxifying activity in pig livers and hepatocytes intended for xenotherapy

BACKGROUND

Both livers and hepatocytes from pigs have been proposed for the treatment of end-stage liver diseases, as an alternative to allogeneic liver transplants. However, little is known of the capability of porcine hepatocytes to fulfill the biotransformation pathways of toxic compounds, including those released from livers in acute failure. We have studied the activity and expression of detoxifying enzymes in porcine livers and in cultured hepatocytes and their induction by phenobarbital.

METHODS

Cytochromes P450 (CYP) 1A, 2B, and 3A and GST-like activities were tested with the following specific substrates: 7-ethoxyresorufin, 7-pentoxyresorufin, nifedipine, testosterone, 1-chloro-2,4-dinitrobenzene, 1,2-dichloro-4-nitrobenzene, and ethacrinic acid. CYP 1A1/2-, 2B1/2-, 2E1- and 3A4-related and GSTalpha proteins were analyzed by Western blotting and CYP 1A1/2, 2B1/2, 2C6, 2E1, and 3A4, aldehyde dehydrogenase, epoxide hydrolase, and GSTalpha-like RNA by Northern blotting.

RESULTS

Enzymatic activities reflecting the expression of CYP 1A-, CYP 2B-, CYP 2E1-, and CYP 3A-like genes, that is, ethoxyresorufin-O-deethylase, pentoxyresorufin-O-deethylase, nifedipine oxidase and testosterone 6beta-hydroxylase, and chlorzoxazone 6-hydroxylase, were identified in pig livers. CYP 1A and CYP 2E1, GSTalpha-like proteins, CYP 1A, 2C, and 2E, epoxide hydrolase, aldehyde dehydrogenase, and GST like RNA were expressed in vivo and in vitro. CYP 2B and CYP 3A RNA and proteins, and their associated activities were induced by phenobarbital.

CONCLUSIONS

Porcine hepatocytes express the most important biotransformation enzymes and their corresponding activities and RNA. Thus, livers and hepatocytes from pigs can detoxify a large spectrum of exogenous and endogenous compounds, which makes them a convenient substitute for allogeneic transplants for patients with liver failure.

Involvement of cyclic nucleotide- and calcium-regulated pathways in phenobarbital-induced cytochrome P-450 3A expression in mouse primary hepatocytes

Several of the hepatic microsomal cytochromes P-450 (CYP) including CYP3A are inducible by phenobarbital (PB). However, the intracellular pathways involved in the action of PB on CYP3A remain poorly known. With the aim to unravel some of the main aspects of PB signaling, we first devised a simple model of mouse cultured primary hepatocytes in which CYP3A mRNA and protein were strongly induced by PB in the absence of dexamethasone and were at maximum levels after a 48-h treatment with a 2-mM dose of PB. Under these culture conditions, we studied the effects of inhibitors and activators of different protein kinases or phosphatases on CYP3A mRNA and protein induction by PB. CYP3A-induced expression was inhibited by activators of cyclic AMP-dependent protein kinase (PKA) (dibutyryl-cyclic AMP and forskolin) whereas inhibition of PKA by PKA inhibitor enhanced induction. 8-br-cGMP produced effects similar to the activators of PKA, and so did the specific inhibitor of cGMP-dependent protein kinase, beta-phenyl-1, N(2)-etheno-8-bromoguanosine-3,5'-cyclic monophosphorothioate, Rp-isomer (Rp-8-Br-PET-cGMPS). Inhibition of Ca(2+)/calmodulin-dependent protein kinase by KN-62 or the intracellular Ca(2+) chelator BAPTA-AM produced an inhibition of CYP3A induction by PB. Specific inhibitors of protein kinase C, mitogen-activated protein kinase kinase, phosphatidylinositol-3-kinase, or serine/threonine phosphatase did not produce any effect. Taken together, our results suggest that CYP3A induction by PB is regulated positively by calmodulin-dependent protein kinase and cGMP-dependent protein kinase, and negatively by PKA in mouse hepatocytes in primary culture.

Isolation of a cyp2b10-like cDNA and of a clone derived from a cyp2b10-like pseudogene

By screening Balb/c male mouse liver cDNA library with a rat CYP2B1 cDNA probe, we have isolated a 1795 bp cyp2b10-like clone, referred to as P16. Its sequence exhibited 34 base differences (98% similarity) with the cyp2b10 published sequence, together with a 97% identity at the amino acid sequence level. By RT-PCR and PCR analyses with Balb/c female and male liver RNA and genomic DNA, using a region showing 8 base differences between the P16 and the cyp2b10 sequences, we have confirmed the identity of our cloned cDNA, and failed in finding a PCR product exhibiting a sequence 100% identical with that of cyp2b10. Our results therefore suggest that the P16 sequence is the authentic cyp2b10 sequence. We have also isolated a partial clone, P21, which 1609 bp sequence overlapped with that of P16, except for a T-->G transversion, giving rise to a premature TGA stop codon, indicating that it was derived from a pseudogene.

Endotoxin suppresses the oltipraz-mediated induction of major hepatic glutathione transferases and cytochromes P450 in the rat

The effect of Escherichia coli lipopolysaccharide (LPS), a classic inducer of the acute-phase response, has been analyzed on both constitutive and oltipraz (a chemoprotective agent)-inducible messenger RNAs (mRNAs) and enzyme activities of major cytochromes P450 (CYPs) and glutathione transferases (rGSTs) in rat liver. At the dose administered (1 mg/kg) and the time studied (6 and 24 hours), endotoxin had no effect on the expression of either CYPs and GSTs with the exception of CYP1A2, which was reduced at both mRNA and activity levels. A strong increase of rGSTA1/2, rGSTM1, rGSTP1, CYP1A2, CYP2B1/2, and CYP2E1 was observed after 3 days of treatment with oltipraz (0.075%, wt/wt). Oltipraz induction of these enzymes (with the exception of CYP2E1) was found to be suppressed at both mRNA, protein, and activity levels during the acute-phase response to endotoxin. Moreover, it is shown that oltipraz induction of CYP1A2 and CYP2B1/2 and its suppression by E. coli LPS occurred at a transcriptional level. These data support the idea that the chemoprotective effect of oltipraz is altered in the course of inflammation and that adaptation in chemoprotective strategies should be considered in certain physiopathologic situations.

Phenobarbital induces cytochrome P4501A2 hnRNA, mRNA and protein in the liver of C57BL/6J wild type and aryl hydrocarbon receptor knock-out mice

The aryl hydrocarbon receptor mediates the transcriptional response to a variety of hydrocarbons of members of the aryl hydrocarbon gene battery. Phenobarbital does not bind the aryl hydrocarbon receptor with high affinity but induces, in liver cells, expression of cytochrome P4501A. Using both wild type and aryl hydrocarbon receptor knock out C57BL/6J mice, we demonstrate that phenobarbital induced hnRNA, mRNA and protein for the cytochrome P-4501A2 gene in the presence or absence of the aryl hydrocarbon receptor. Using the DNA binding site for the aryl hydrocarbon receptor as a probe, gel retardation analyses showed that phenobarbital treatment induced protein binding, regardless of the presence of the aryl hydrocarbon receptor.

Reparative surgery of valves in the treatment of superficial venous insufficiency. External banding valvuloplasty versus high ligation or disconnection. A prospective multicentric trial

OBJECTIVE

A prospective study was performed in order to compare results obtained in the treatment of early and/or limited primary varicose veins of the lower limbs using two different procedures: external valvuloplasty and high ligation or disconnection of the sapheno-femoral junction.

MATERIALS AND METHODS

116 limbs (113 patients) were selected. 57 with normal cusps in dilated valves were subjected to external valvuloplasty with Silicone prosthesis under Doppler control (intraoperative angioscopy in 16 cases); 59 limbs were subjected to high ligation or disconnection of the junction; 57 limbs out of 116 were subjected to complementary procedures. Duplex and photoplethysmographic examinations were performed before and after the surgical procedures in all patients. Doppler venous pressures were measured in 36 limbs and invasive pressures in 40 limbs. Patients were postoperatively followed up every 4 months until the 12th month.

RESULTS

Indications for valvuloplasty were found in 8.2% of cases and in 66.3% of the early varices. Clinical results were slightly superior in the reparative surgery group. Thrombotic occlusion of the proximal long saphenous vein was significantly higher in the ligation-disconnection group. Results from photoplethysmography and venous pressure measurements indicated that both operations are equally effective in the elimination of reflux in the junction.

Regulation of the major detoxication functions by phenobarbital and 3-methylcholanthrene in co-cultures of rat hepatocytes and liver epithelial cells

In the present study, we analysed the expression of monooxygenase activities and mRNAs associated with cytochrome P-450 (CYP), including CYP1A1/2, CYP2B1/2, CYP2C6, CYP2E1, CYP3A1/2, glutathione transferase alpha (GST alpha), aldehyde dehydrogenase and epoxide hydrolase in co-cultures of primary rat hepatocytes and rat liver epithelial cells. We observed that pentoxyresorufin O-deethylation activity was well maintained and ethoxyresorufin O-deethylation activity gradually decreased during co-culture time. In addition, we showed that phenobarbital and 3-methylcholanthrene treatments resulted in a significant increase of these activities. Two general patterns of accumulation of liver-specific mRNAs were observed. CYP1A1/2, CYP2B1/2, CYP3A1/2, GST alpha, aldehyde dehydrogenase and epoxide hydrolase mRNAs were maintained at a stable level, whereas CYP2C6 and CYP2E1 mRNAs showed a continuous decline. In addition, we observed a strong increase of CYP1A1/2 (13.6-fold) and GST alpha (3.9-fold) mRNA expression in 3-methylcholanthrene-treated co-cultures and induction of CYP2B1/2 (19-fold), CYP2C6 (10-fold), CYP3A1/2 (11.2-fold), GST alpha (9-fold), aldehyde dehydrogenase (6-fold) and epoxide hydrolase (5-fold) mRNA expression in phenobarbital-treated co-cultures. Furthermore, we demonstrated that liver-specific gene expression was restricted to hepatocytes, with the notable exception of epoxide hydrolase and CYP2E1 which were expressed in both cell types during the co-culture, as shown by the selective recovery of both hepatocytes and rat liver epithelial cells. Finally, to investigate whether co-cultures could be used to study the molecular mechanisms regulating CYP transcription, we performed transfection of hepatocytes, before the establishment of the co-culture, with large CYP2B1 (3.9 kb) or CYP2B2 (4.5 kb) promoter chloramphenicol acetyltransferase constructs or with a construct containing a 163-bp DNA sequence element reported to confer phenobarbital responsiveness. A 2-3-fold increase over the basal level of chloramphenicol acetyltransferase activity was observed in phenobarbital-treated co-cultures transfected with the phenobarbital-responsive element construct, although phenobarbital had no effect on large CYP2B1 or CYP2B2 promoter fragments. Our results demonstrate that the co-culture system provides a good tool for studying drug metabolism, and shows promise as a new tool for analysing transcriptional regulation under the influence of xenobiotics within primary hepatocytes.

Collateral circulation in distal occlusion of lower limb arteries: an anatomical study and statistical research in 40 elderly subjects by echo-color-Doppler method

The collateral circles and their hemodynamic significance in distal lower limb arterial occlusion have been described in an elderly population. Overall 40 subjects (20 men and 20 women; age range 66-83) with symptomatic lower limb arteriopathy (Fontaine's stage II) have been studied combing Contrast Angiography and Color Doppler Echography of the lower limb arterial district. In our population, the results showed that the tibialis arteries were the vessels most often involved in arterial occlusion (posterior tibialis a., 15 cases = 37.5%, posterior tibialis a., 12 cases = 30%), followed by the peroneal a. (8 cases = 20%) and by the popliteal a. (5 cases, 12.5%). In the occlusion of the popliteal artery the collateral circle was mainly established through the deep femoral a., the great anastomotic a., the recurrent posterior tibialis a., and from the articular supero-lateral a. In the occlusion of the anterior tibialis artery the collateral circulation was ensured through the collateral posterior tibialis as. and through the collateral perineal as. In the occlusion of the posterior tibialis a., the collateral circle was established through the great anastomotic a., through the branchers of the arterial circle of the ankle and from the perforating plantar as. (anterior tibial a.). Finally, in the occlusion of the peroneal a., the collateral circulation was only represented by branches of the arterial circle of the ankle. The hemodynamic compromission, measured by the Windsor Index, was the highest for popliteal occlusions (mean IW = 34.3%). Occlusions of the anterior tibialis a. (mean IW. = 35.48%), of the peroneal a. (mean IW = 44.71%), and of the posterior tibialis a. (mean IW = 55.44%) showed progressively lower hemodynamic compromission. Gender differences in hemodynamic significance at each level of occlusion were not significant.

Sapheno-femoral valves. Histopathological observations and diagnostic approach before surgery

BACKGROUND

Since the literature indicated that in the early stages of primary venous disease valves are simply dilated, some authors performed external valvuloplasty of deep and superficial venous valves with encouraging results, although some failures were observed without being sufficiently explained.

OBJECTIVE

To obtain further interpretations of the natural history of venous valve pathology, clarify methods for a correct diagnostic approach, and provide indications for the external valvuloplasty procedure.

METHODS

Forty-two proximal valves of the long saphenous vein removed for varicose veins of the lower limbs were studied with optical microscopy. The relationship between histologic alterations and age of varicose disease was investigated. Five valvuloplasties were explanted for recurrent reflux and submitted to histopathological observation. Preoperative echographic findings and histologic observations were compared. Nineteen limbs were subjected to external valvuloplasty under angioscopic control; preoperative echographic findings and angioscopic observations were compared.

RESULTS

The histologic alterations observed in venous valves were mainly hypotrophy of cusps, which seemed to be the main cause of failure after external valvuloplasty. The frequency of such hypotrophic alterations increases with the age of varicose disease but no statistically significant relationship was found. Preoperative echographic imaging of venous valves does not appear sufficiently predictive when compared with histologic and angioscopic examinations.

CONCLUSION

Hypotrophic valve damage seems to be prevalent in patients with varicose veins of the lower limbs. Valve cusp hypotrophy may be present in early disease though some normal cusps can be found in advanced disease. When preoperative echographic visualization of cusps is doubtful, intraoperative angioscopy plays the main role in the diagnosis of venous valve disease before and during external valvuloplasty.

Isolation of a new mouse cDNA clone: hybrid form of cytochrome P450 2b10 and NADPH-cytochrome P450 oxidoreductase

We have isolated a novel cDNA sequence from a male mouse liver library. It consists of an open reading frame containing no stop codon of 1348 bp which share 98% similarity with the cytochrome P450 2b10 followed by 95 nucleotides sharing 88% identity with the mouse NADPH cytochrome P450 oxidoreductase. Proteins are encoded by the opposite DNA strands. Genomic amplification excludes a library artefact or a de novo recombination event. RT-PCR analyses revealed expression of this clone in the liver of male and female mice as well as in kidney, lung and intestine. This cDNA was not, however, induced by phenobarbital. Preliminary results indicate that this cDNA could span more than 2.5 kb. This study is the first description of a cytochrome P450 cDNA sequence encoding part of both a cytochrome P450 and the NADPH cytochrome P450 oxidoreductase in mammalian liver.

Genetic analysis of the phenobarbital regulation of the cytochrome P-450 2b-9 and aldehyde dehydrogenase type 2 mRNAs in mouse liver

The aim of this study was to investigate the effect of the genetic background on the phenobarbital inducibility of cytochrome P-450 2b-9, cytochrome P-450 2b-10 and aldehyde dehydrogenase type 2 mRNAs in mice. We analysed the basal expression and the phenobarbital inducibility of both cytochrome P-450 mRNAs by semi-quantitative specific reverse transcription-PCR analyses in five inbred mouse strains (A/J,BALB/cByJ,C57BL/6J, DBA/2J and SWR/J). Male mice constitutively expressed cytochrome P-450 2b-9 and cytochrome P-450 2b-10 mRNAs, but a number of differences in their response to phenobarbital were observed. In all these mouse strains, phenobarbital induced cytochrome P-450 2b-10 mRNA whereas it could have either a positive or a negative effect on cytochrome P-450 2b-9 expression, depending on the strain and the sex of the mice. Specifically, phenobarbital increased cytochrome P-450 2b-9 expression in C57BL/6J males while it decreased it in DBA/2J mice. Interestingly, dexamethasone was able to mimic the phenobarbital effect on both cytochromes P-450 in these two strains. Aldehyde dehydrogenase type 2 mRNA was always induced by phenobarbital, except in the C57BL/6J strain. Genetic analysis revealed that the phenobarbital-inducible phenotype was either a semi-dominant or a recessive trait in F1 animals from a C57BL/6J x DBA/2J cross for the cytochrome P-450 2b-9 and the aldehyde dehydrogenase type 2 genes, respectively. This study suggests that the genetic basis for phenobarbital induction in mice depends on the target gene, and that more than one regulatory step would by involved in this response pathway.

trans-Acting factors, detoxication enzymes and hepatitis B virus replication in a novel set of human hepatoma cell lines

A panel of four novel human hepatoma cell lines was isolated from a single tumor from a male individual. BC1, B16 and B16A2 lines were well differentiated, while cells of the B9 line were only poorly differentiated, being essentially negative for the functions analyzed. These cell lines have been surveyed for expression of a large set of plasma proteins, accumulation of liver-specific mRNAs and DNA-binding activity of ubiquitous and liver-enriched transcription factors. BC1 cells expressed the highest levels of albumin mRNA, whereas B16 and B16A2 cells accumulated the largest amounts of haptoglobin mRNA. In addition, B16 and B16A2 cells were unique in that they expressed CYP2E1 mRNA, a species absent from the available human liver cells, including HepG2 hepatoma cells, and 3-methylcholanthrene-inducible CYP1A2 mRNA. The activities of genes encoding transcription factors were evidenced in all four cell lines which expressed mRNAs for nuclear factor interleukin 6 and hepatocyte nuclear factor 1 (HNF) together with the DNA-binding activity of NFY and AP1 nuclear proteins. Strikingly, HNF-1 and HNF-4-like DNA-binding activities were restricted to BC1, B16 and B16A2 cells, supporting the idea of the potential role of these (or closely related) factors in the maintenance and/or in the establishment of the differentiated phenotype. B9 cells contained variant HNF1-like DNA-binding activity, similar to dedifferentiated rat hepatoma cells of the H5 line. CCAAT/enhancer-binding protein and HNF-3-like activities were found in all cell lines, although at a lower level and/or activity in B9 cells. Finally, transfection experiments of plasmids containing the whole hepatitis-B virus genome demonstrated that B16 cells, but not B9 cells, were able to support hepatitis-B virus replication and virion production, in agreement with the notion that HNF-1 activity is necessary for viral replication. We believe that the specific complement of transcription factors expressed in the differentiated BC1, B16 and B16A2 cells, and in the poorly differentiated B9 cells, will allow studies on the regulation of hepatic gene expression in these human lines, and will also aid the analysis of xenobiotic metabolism and the biology of hepatitis-B virus replication.

Rat liver epithelial cells express functional cytochrome P450 2E1

Rat liver epithelial cells (RLECs) isolated by trypsinization of the livers of normal 10 day old rats are largely used in co-culture with primary hepatocytes. The aim of the present study was to investigate the expression of biotransformation enzyme-encoding genes in three preparations of RLEC lines. Although no expression of cytochrome P450 1A1/2 (CYP1A1/2), CYP2B1/2, CYP2C6 or CYP3A mRNAs could be detected, we found that all of the different preparations of RLECs expressed a high level of CYP2E1 mRNA. We demonstrated the presence of the CYP2E1 apoprotein in microsomes of RLECs by immunoblot analyses, together with chlorzoxazone 6-hydroxylation, an activity known to be mainly catalyzed by CYP2E1. In addition, acetone treatment of these cells resulted in an increase in both CYP2E1 apoprotein and chlorzoxazone 6-hydroxylation activity levels. Finally, we showed the susceptibility of RLECs to N-methyl formamide- and diethylnitrosamine-induced toxicity, suggesting metabolic activation by CYP2E1. Thus, RLECs may cooperate with hepatocytes to CYP2E1-mediated metabolism in the co-culture model. In addition, transfection experiments with a CYP2E1 promoter construct, in which the proximal 539 bp containing the binding site for HNF1alpha were inserted upstream of the chloramphenicol acetyl transferase gene, demonstrated a strong induction upon co-transfection with an HNF1alpha expression plasmid. Thus, RLECs provide a useful tool for studying metabolism and cytotoxicity of CYP2E1 substrates in the absence of other expressed CYPs, and for analyzing CYP2E1 promoter function.

Collateral circulation in occlusion of lower limbs arteries: an anatomical study and statistical research in 35 old subjects

The collateral circles formed following lower limbs arterial occlusion and their hemodynamic function have been described; 35 subjects (23 men and 12 women; age range 65 to 80), with symptomatic lower limbs obstructive arteriopathy (Fontaine's stage II) following occlusion of vessels downstream the subrenal aorta have been studied by means of Contrast Angiography and Color Doppler Echography of the vascular district including the terminal aorta and the lower limbs arteries. The hemodynamic significance of the collateral circles was assessed by calculating the Windsor index. In this population, the collateral circles for each level of obstruction were explored. Occlusion of the terminal abdominal aorta: the collateral circle was mainly established through the inferior mesenteric and ischiatic arteries and through the lumbar, ilio-lumbar and gluteal arteries; occlusion of the iliac tract: the collateral circulation was established through the spermatic or ovaric artery and through the funicular, external pudendal and middle sacral arteries; occlusion of the ilio-femoral tract: the collateral circulation was formed by the internal and external pudendal arteries and by the ilio-lumbar, obturating, gluteal and circumflex iliac arteries; occlusion of first tract of the superficial femoral artery: collateral circulation was established through the deep femoral artery and through the perforating arteries; occlusion of the terminal tract of the superficial femoral artery: collateral circulation was formed by the articular branches of the same artery originating proximal to the occlusion and through branches of the deep femoral artery; occlusion of the superficial and deep femoral arteries at their origin: collateral circulation was established through the ischiatic artery (directly and, indirectly, through the perforating arteries), and through the tegumental arteries. The hemodynamic significance, as measured by Windsor index was higher the more proximal was the occlusion, in accord with the lower caliber and/or number of vessels involved in the collateral circles.

Magnetic resonance angiographic evaluation of circulus arteriosus cerebri (circle of Willis): a morphologic study in 100 human healthy subjects

The Circle of Willis was studied by Magnetic Resonance Angiography in 100 healthy subjects. In 41% of these cases, the arteries were arranged in the classically described way. In 21%, hypoplasia of the posterior communicating as. was noted, while in 13% the posterior cerebral as were found to originate from the internal carotid a.. In 9% of these cases, three anterior cerebral as. were present. In 3% the anterior communicating artery could not be identified, while the left posterior communicating artery was hypoplastic. In 2% the absence of a posterior communicating artery was associated with the origin of a posterior cerebral a. from the internal carotid. In another 2% the anterior cerebral as. were partially fused, and in yet another 2%, hypoplasia of both an anterior and a posterior cerebral a. was present. The remaining seven cases (7%), all different from each other, represented combinations of the above described variations. Statistical analysis indicated that anomalies occurred more commonly on the left than on the right side. The morphology of the Circle of Willis could not be correlated with either sex or Body Index.

Internal diameters of human femoral blood vessels in 50 healthy subjects using color Doppler ultrasonography

50 healthy subjects (25 men and 25 women; age range: 18 to 80 years) have been examined. The internal calibers of the common femoral artery, of the superficial femoral artery, of the common femoral vein, and of the superficial femoral vein have been measured in selected locations using Color Doppler Ultrasonography. The difference in vessel caliber between men and women was statistically significant (p < 0.01). There was no significant difference in left versus right vessel calibers for all the four vessels studied. In the same subject, vessel caliber was directly proportional in the left compared to the right side (p < 0.01). Both in the left and in the right side, arterial and venous calibers of the same subject in the same side were directly proportional (p < 0.01). The relationship between the calibers of the four vessels under study and age, height, and body surface area were not statistically significant.

A comparison of the effect of inducers on the expression of glutathione-S-transferases in the liver of the intact rat and in hepatocytes in primary culture

Recently, we used human hepatocytes in primary culture to study the effects of inducers of glutathione-S-transferases (GSTs) in the expectation that information obtained can be used to predict the value of particular inducers for use in the chemoprevention of cancer and other toxicities. However, in vitro human studies cannot readily be confirmed by studies in vivo. This problem does not arise in experimental animals. In the current studies, the response of male rat hepatocytes in primary culture to the following inducers of GST isoenzymes has been determined: 3-methylcholanthrene (MC); phenobarbital (PB); 1,2-dithiole-3-thione and its 5-(2-pyrazinyl)-4-methyl derivative, oltipraz (OPZ), and the results have been compared with induction obtained in livers of MC- and OPZ-treated rats. Each type of inducer was found to elicit a different response. In vitro, phenobarbital increased messenger RNA (mRNA) levels of subunits 1b and 3 after 12 and 72 hours, respectively; MC had a rapid effect on GST alpha class mRNAs (bringing about increase after only 2 hours of treatment), increased subunit 7 mRNA slightly, and had no effect on mu class mRNAs; dithiolethiones induced both subunit lb and 7 mRNAs after 4 hours and, to a much lower extent, subunit 3 mRNA after 72 hours. In vivo, MC induced significantly both subunit lb and 7 mRNAs whereas OPZ increased significantly subunits lb, 3 and 7 mRNA levels, and to a lower extent those of subunit 2, after 3 days and beyond to at least 5 days of treatment. Results obtained in mRNA studies were confirmed by high-pressure liquid chromatography (HPLC) analysis of GST subunits. HPLC also showed an induction of subunit 10 at the protein level of which the mRNA was not analyzed. Our results show that rat hepatocytes in primary culture prove to be a good model for the effect of inducers on both the expression of GST mRNA and protein levels in the rat liver in vivo. The demonstration of this good correlation in the rat with respect to increases gives support for the use of human hepatocytes for predictive studies of chemoprotection in human pharmacology.

The inner diameter of human intracranial vertebral artery by color Doppler method

In 50 healthy subjects the internal diameter of the intracranial vertebral artery were measured by echocolor doppler method. The diameter of left vertebral a. was greater than that of the right in most subjects (58%); the mean left/right difference was statistically significant (p < 0.05). Analyzing men and women separately, the difference remained significant only in women (p < 0.05). A significant correlation was found between vertebral a. diameter and sex (p < 0.01). The vertebral a. diameter had a tendency to increase with age, that reached significance only for the left vertebral one. No significant correlation was found between body surface area and vertebral a. diameter.