Disruption of actin cytoskeleton induces chondrogenesis of mesenchymal cells by activating protein kinase C-alpha signaling

Disruption of actin cytoskeleton with cytochalasin D has been known to induce chondrogenic differentiation of chick embryo limb bud mesenchymal cells. However, the mechanism(s) for the induction of chondrogenesis by cytochalasin D is not yet clearly known. In the present study, we examined possible involvement of protein kinase C (PKC) and extracellular signal-regulated protein kinase (Erk-1) in chondrogenesis of mesenchymal cells induced by disruption of actin cytoskeleton. Disruption of actin cytoskeleton with cytochalasin D or latrunculin B induced chondrogenesis of mesenchymal cells cultured at subconfluent cell density, as determined by type II collagen expression. Among the expressed PKC isoforms, cytochalasin D dramatically increased expression and activation of PKCalpha in a dose-dependent manner, and inhibition or downregulation of PKCalpha blocked cytochalasin D-induced chondrogenesis. Cytochalasin D also downregulated Erk-1 phosphorylation that is associated with chondrogenesis. Our results, therefore, suggest that disruption of actin cytoskeleton induces chondrogenesis of mesenchymal cells by activating PKCalpha and by inhibiting Erk-1 signaling.

Inhibitory effect of PGE2 on EGF-induced MAP kinase activity and rabbit corneal epithelial proliferation

PURPOSE

To determine in rabbit corneal epithelial cells in culture whether epidermal growth factor (EGF)-induced increases in prostaglandin (PG) E2 production inhibit both the extracellular signal-regulated kinase 2 (Erk-2), a mitogen-activated protein kinase (MAPK), cascade activation, and the mitogenic response to this growth factor.

METHODS

Serum starvation for 24 to 36 hours was used to synchronize cultures of SV40-transformed rabbit corneal epithelial (RCE) cells. The effects of exogenous PGE2, inhibition of PGE2 synthesis, and modulation of protein kinase A (PKA) activity on EGF-induced Erk-2 activation were assessed by immunoprecipitation, kinase assays, and Western blot analysis. PGE2 synthesis was measured by using enzyme-linked immunosorbent assay. [3H]-Thymidine incorporation was used to measure RCE cell proliferation rates.

RESULTS

EGF (5 ng/ml) significantly increased PGE2 production in a time-dependent manner up to 94%+/-8% after 3 hours. EGF-induced PGE2 production was suppressed by AACOCF3, a phospholipase A2 (cPLA2) inhibitor. EGF-induced Erk-2 activation reached a maximal level at 15 minutes, followed by a decline toward the control level after 3 hours. In the presence of either PGE2 (50 microg/ml) or 8-CPT-cAMP (100 microM), the EGF-induced Erk-2 activation was lessened. PKA was activated by applications of EGF or PGE2 and suppressed by AACOCF3. On the other hand, either inhibition of PGE2 production with AACOCF3 or H-89, a PKA inhibitor, enhanced EGF-induced Erk-2 activity. Raf-1 activity was stimulated by EGF to maximal activity at 5 minutes and returned toward its control level after 60 minutes. As with the dependence of Erk-2 activity on PKA activity, in the presence of H-89, the EGF-induced Raf-1 activation was significantly enhanced. DNA synthesis was increased 59%+/-5% (n = 4) after EGF stimulation, indicating a mitogenic effect of EGF in RCE cells. Inhibition of cPLA2 activity with AACOCF3 increased DNA synthesis in RCE cells by another 64% relative to the effect of EGF alone. In contrast, with either PGE2 or 8-CPT-cAMP present the mitogenic response to EGF was totally suppressed.

CONCLUSIONS

EGF-induced increases in PGE2 production dampened the mitogenic response to this growth factor. This suppression appears to be a consequence of PGE2-elicited increases in PKA activity, which leads to inhibition of EGF-induced activation of MAPK cascades at the level of Raf-1 and further affects downstream events including Erk-2. These results indicate that the mitogenic response to EGF in vivo in the proliferating basal cell layer may be dependent on the level of its PKA activity.

Optimising the performance of intermittent pneumatic compression devices

OBJECTIVES

this study was designed to determine whether an intermittent pneumatic compression device (IPC) with an increased maximal inflation pressure, a decreased time to maximal pressure and a longer duration of compression would improve venous return compared to a standard IPC device.

METHODS

thirty limbs in 15 volunteers without evidence of venous disease were studied using duplex scanning at rest and during the application of two different IPC devices with different compression parameters. The first device IPC-1 (SCD 5325, Kendall) has a six-chambered cuff applying 45 mmHg after 12 s, sequentially from ankle to thigh followed by 60 s of non-compression. The second device IPC-2 (Vena-Assist(R), ACI Medical) has a foot, ankle and calf cuff, applies a pressure of 80 mmHg, has a pressure rise time of 0.3 s, maintains inflation for 5.5 s, and has a cycling time of 1 min. Peak venous velocity and acceleration time were measured at rest and during the IPC application. Measurements were obtained in supine position from the common femoral vein 1 cm above the saphenofemoral junction to include the entire venous outflow from the limb.

RESULTS

peak venous velocity at rest was significantly higher in the right limb than in the left limb (26+/-7.2 vs. 22+/-5.7 cm/s, p<0.01). Peak venous velocity was significantly increased by both IPC devices (p <0.0001). IPC-2 achieved significantly higher peak venous velocity than IPC-1 (55.1+/-17.8 vs. 37.4+/-6.9 cm/s, p<0.0001). Acceleration time was also found to be significantly shorter (370+/-93.4 vs. 560+/-83.5 ms, p<0.0001) in IPC-2 than in IPC-1, respectively.

CONCLUSIONS

we have demonstrated that progressive inflation at the foot, ankle and calf, increasing maximal inflation pressure and decreasing time to maximal pressure result in increased venous return. These changes may improve the efficacy of IPC devices in the prevention of deep-venous thrombosis (DVT) formation.

Rhodococcus koreensis sp. nov., a 2,4-dinitrophenol-degrading bacterium

A 2,4-dinitrophenol-degrading bacterial strain, DNP505T, which was isolated from an industrial wastewater, was taxonomically studied by a polyphasic approach using phenotypic, chemotaxonomic and genetic methods. Strain DNP505T has a cell wall of chemotype IV containing meso-diaminopimelic acid, arabinose and galactose. The predominant menaquinone is MK-8(H2). Mycolic acids contain 43-53 carbon atoms. Strain DNP505T has a cellular fatty acid profile containing straight-chain saturated, unsaturated and 10-methyl-branched fatty acids and has C16:0 as the major fatty acid. The DNA G+C content is 66 mol%. Strain DNP505T formed a coherent cluster with Rhodococcus species in a phylogenetic inference based on 16S rDNA sequences. Interestingly, strain DNP505T was found to have two types of 16S rDNA sequence, which showed 10 bp sequence differences (99.3% nucleotide similarity). Its differences in some phenotypic characteristics and its genetic distinctiveness indicate that strain DNP505T is separate from Rhodococcus species described previously. It is therefore proposed that strain DNP505T should be placed in the genus Rhodococcus as a new species, Rhodococcus koreensis. The type strain of the new species is strain DNP505T (= KCTC 0569BPT = JCM 10743T).

Effect of interleukin-1beta on gonadotropin-releasing hormone (GnRH) and GnRH receptor gene expression in castrated male rats

Increasing evidence suggests that interleukin-1beta (IL-1beta) regulates luteinizing hormone (LH) release primarily through modulation of the gonadotropin-releasing hormone (GnRH) neuronal activity. This study was undertaken to elucidate the effect of IL-1beta on GnRH as well as GnRH receptor (GnRHR) gene expression in the preoptic area. IL-1beta (100 ng/rat) or saline was administered into the lateral ventricle of castrated rats. RNA samples were isolated from micropunches of the preoptic area and mediobasal hypothalamus from individual brain slices and GnRH mRNA levels in the preoptic area and GnRHR mRNA levels in the mediobasal hypothalamus were determined by competitive reverse transcription-polymerase chain reaction (RT-PCR) protocols. Serum LH concentrations were decreased from 1 h to 3 h after IL-1beta treatment, but rebounded at 5 h, while serum concentrations of follicle-stimulating hormone (FSH) and prolactin were not altered. There were no significant changes in GnRH mRNA levels from the micropunched preoptic area, while GnRHR mRNA levels from the preoptic area and mediobasal hypothalamus micropunch samples, but not in the anterior pituitary, showed a pattern similar to the serum LH profile following i.c.v. administration of IL-1beta. We then examined the effect of IL-1beta on the translational efficiency of the GnRH mRNA. After the separation and fractionation of polyribosome-associated cytoplasmic RNA from the hypothalamic fragments containing the preoptic area-anterior hypothalamic area of control (saline-treated) and IL-1beta-treated group 3 h after administration, GnRH transcript levels were examined from the each fraction. IL-1beta decreased the translational efficiency of the transcribed GnRH mRNA. These results clearly demonstrate that central administration of IL-1beta suppresses the translational activity of GnRH mRNA. Moreover, GnRHR may play an important role in the modulation of GnRH neuronal activity through GnRHR-expressing neurones (or glia) in the hypothalamus.

Gordonia nitida sp. nov., a bacterium that degrades 3-ethylpyridine and 3-methylpyridine

A bacterial strain, LE31T, which is capable of degrading 3-ethylpyridine and 3-methylpyridine, was isolated from an industrial wastewater and was taxonomically studied by using a polyphasic approach. Strain LE31T was identified as a member of the genus Gordonia on the basis of chemotaxonomic characteristics and phylogenetic inference-based 16S rDNA sequence. The cell wall contained meso-diaminopimelic acid, arabinose and galactose (wall chemotype IV). The predominant menaquinone was MK-9(H2). The mycolic acids contained 47-55 carbon atoms. The major fatty acids were C16:0, C18:1 omega9c, 10-methyl-C18:0 (TBSA). The G+C content of DNA was 67 mol%. The 16S rDNA sequence of strain LE31T was most similar to that of the type strain of Gordonia rubropertincta. The differences in some phenotypic characteristics and the genetic distinctiveness distinguish strain LE31T from the Gordonia species described previously. Therefore it is proposed that strain LE31T should be placed in the genus Gordonia as a new species. The name Gordonia nitida is proposed for strain LE31T. The type strain of the new species is strain LE31T (= KCTC 0605BPT = KCCM 80004T).

Epidermal growth factor negatively regulates chondrogenesis of mesenchymal cells by modulating the protein kinase C-alpha, Erk-1, and p38 MAPK signaling pathways

During limb development, epithelial cells in the apical ectodermal ridge keep the underlying mesenchymal cells in a proliferative state preventing differentiation by secreting signaling molecules such as epidermal growth factor (EGF). We investigated the molecular mechanism of the EGF effect on the regulation of micromass culture-induced chondrogenesis of chick limb bud mesenchymal cells as a model system. We found that expression and tyrosine phosphorylation of the EGF receptor was increased transiently during chondrogenesis. Exogenous EGF inhibited chondrogenic differentiation of mesenchymal cells, and this effect was reversed by the EGF receptor inhibitor AG1478. EGF treatment also inhibited the expression and activation of protein kinase C-alpha, whereas it activated Erk-1 and inhibited p38 mitogen-activated protein kinase, all of which appeared to be involved in the EGF-induced inhibition of chondrogenesis. Stimulation of the EGF receptor blocked precartilage condensation and altered the expression of cell adhesion molecules such as N-cadherin and integrins alpha(5) and beta(1). All these EGF effects were reversible by AG1478. The data indicate that EGF negatively regulate chondrogenesis of chick limb bud mesenchymal cells by inhibiting precartilage condensation and by modulating signaling pathways including those of protein kinase C-alpha, Erk-1, and p38 mitogen-activated protein kinase.

Current surgical results of retrosigmoid approach in extralarge vestibular schwannomas

BACKGROUND

Vestibular schwannomas (VS) are common tumors that can be cured; they are reported to comprise 6 approximately 8% of all intracranial tumors. The primary objective in the surgery of extralarge VS is total removal of the tumor mass while preserving the facial nerve. In extralarge tumors, complete excision of the tumor carries a significant risk of injuring the facial nerve and adjacent vital brain structures. The authors are reporting the techniques and results of operation on extralarge VS.

METHODS

The material consisted of 30 patients during the last 6 years with surgically treated VS that had a maximal extrameatal diameter exceeding 4 cm. Suboccipital craniotomy and tumor removal was performed with patients in the lateral position. Results and complications of the surgical technique will be reviewed.

RESULTS

Average age of patients was 45.2 years; there was a slight female predominance (1.5:1). Size of the mass ranged from 41 to 70 mm; all were removed by the retrosigmoid transmeatal approach. Peritumoral edema on MRI was seen in 50% (15/30). Total removal was achieved in 73.3% (22/30) with no significant relationship to peritumoral edema. In the cases of total removal, the facial nerve preservation rate was 86.4% (19/22). There was no mortality. Surgical complications were hemorrhage and CSF leakage in 1 case (3%) and 8 cases (26.7%), respectively, but in most of these cases, conservative treatment was adequate. In patients in whom anatomic preservation of the facial nerve was achieved, facial nerve function improved progressively within a year. In all cases except for one with gait disturbance, a good outcome was achieved.

CONCLUSIONS

Our surgical techniques, including the prediction of facial nerve displacement, not using retractors, and replacement of bone, contributed to good surgical results in a series of extralarge VS.

Expression of pituitary adenylate cyclase activating polypeptide (PACAP) and PACAP type I A receptor mRNAs in granulosa cells of preovulatory follicles of the rat ovary

Pituitary adenylate cyclase activating polypeptide (PACAP) was isolated from ovine hypothalamus and known to stimulate the production of cAMP in anterior pituitary cells. In the recent report, the expression of PACAP was detected in preovulatory follicles, and treatment with PACAP stimulated the production of progesterone and prostaglandin E(2) through the action of AC and PLC pathways in the ovary. PACAP binds to three type receptors. Type I A receptor is coupled to adenylate cyclase (AC) and phospholipase C (PLC) pathways, while type I B and type II receptors are only coupled to AC. Thus, the present study aimed to evaluate the temporal expression of PACAP and its type I A receptor mRNAs in the rat ovary after treatment with pregnant mare's serum gonadotropin and human chorionic gonadotropin (hCG). Northern blot analysis showed that PACAP transcripts were transiently expressed from 3-9 hr after hCG treatment, reaching a maximum at 6 hr. During these time points, PACAP mRNAs were specifically and strongly expressed in granulosa cells and cumulus cells of large preovulatory follicles and interstitial glandular cells. Type I A receptor mRNAs were also transiently expressed in granulosa cells of large preovulatory follicles from 3-9 hr after hCG treatment. PACAP and its type I A receptor mRNAs were expressed in the same preovulatory follicles. These results demonstrate that PACAP acts as an autoregulator or pararegulator through type I A receptor in granulosa cells and cumulus cells of large preovulatory follicles. Thus, we suggest that PACAP may have a critical role in granulosa cells of preovulatory follicles for the preparation of ovulation.

Viscoelastic properties of normal and atherosclerotic carotid arteries

BACKGROUND

remodelling of the arterial wall occurs with ageing, even in the absence of atherosclerotic risk factors. With increasing age, arteries dilate, thicken, and get stiffer. The aim of this study was to correlate carotid artery stiffness with wall thickness and plaque presence between healthy individuals and patients with early and advanced atherosclerosis.

METHODS

twenty healthy volunteers, 40 carotid segments and 90 patients, 174 carotid segments, with vascular disease were included in the study. The carotid artery was imaged longitudinally and measurements of the intimal-medial thickness (IMT) and plaque were obtained. Systolic and diastolic blood pressures were taken from each arm. The carotid artery stiffness (pressure-strain elastic modulus, Ep) was calculated in all sites from the changes in pressure and diameter. M-mode was used to detect the diameter change (systolic to diastolic) over five cardiac cycles.

RESULTS

in the healthy volunteers there was no evidence of plaque or increased IMT. The mean IMT was significantly higher in the patients compared to control (0.83+/-0.27 mm vs. 0.54+/-0.08 mm, p <0.0001). The IMT had a poor correlation with Ep at lower thickness (r=0.24, p=0.08) but this association became stronger with increasing thickness (r=0.62, p<0.001). Arterial segments with an IMT 5 0.88 mm became significantly stiffer compared to the controls (p<0.001) and to patients with an IMT<0.88 mm (p <0.01). Carotid Ep was markedly greater in arterial segments with plaques than in those with increased IMT (p <0.001) and the controls (p<0.0001).

CONCLUSIONS

carotid wall areas with small increase in IMT have a poor correlation with carotid artery stiffness. The carotid stiffness increases in areas with marked wall thickening and particularly in segments with plaque. The simultaneous study of vessel-wall elastic behaviour with IMT and plaque changes may increase our understanding of atherosclerotic progression and wall remodelling.

Opposing role of mitogen-activated protein kinase subtypes, erk-1/2 and p38, in the regulation of chondrogenesis of mesenchymes

The present studies were performed to determine subtype-specific roles of mitogen-activated protein kinase in chondrogenesis. Erk-1/2 activities, downstream of protein kinase C, decreased as chondrogenesis proceeded, whereas p38 activities, independent of protein kinase C, continuously increased during chondrogenesis. Inhibition of Erk-1/2 with PD98059 enhanced chondrogenesis up to 1. 7-fold, whereas inhibition of p38 with SB203580 reduced it to about 30% of the control level. Inhibition of Erk-1/2 or p38 did not affect precartilage condensation. However, cartilage nodule formation was significantly blocked by the inhibition of p38, whereas Erk-1/2 inhibition did not affect it. Modulation of chondrogenesis by the inhibition of Erk-1/2 and p38 was accompanied by altered expression of adhesion molecules in an opposite way. Expression of N-cadherin was reduced as chondrogenesis proceeded. Inhibition of p38 caused sustained expression of N-cadherin, whereas Erk-1/2 inhibition accelerated the reduction of N-cadherin expression. Expression of integrin alpha5beta1 and fibronectin were found to transiently increase during chondrogenesis. Inhibition of p38 caused continuous increase of expression of these molecules, whereas Erk-1/2 inhibition accelerated the decrease of expression of these molecules at a later period of chondrogenesis. Because temporal expression of these adhesion molecules regulates chondrogenesis, the above results indicate that Erk-1/2 and p38 conversely regulate chondrogenesis at post-precartilage condensation stages by modulating expression of adhesion molecules.

Expanded indications for ultrasound-guided thrombin injection of pseudoaneurysms

PURPOSE

We previously reported preliminary data on a new procedure that we developed for the treatment of femoral pseudoaneurysms after catheterization. This study presents our current results of percutaneous ultrasound-guided thrombin injection for treating pseudoaneurysms that arise from various locations and causes.

METHODS

Between February 1996 and May 1999, we performed thrombin injection of 83 pseudoaneurysms in 82 patients. There were 74 femoral pseudoaneurysms: 60 from cardiac catheterization (36 interventional), seven from peripheral arteriography (four interventional), five from intra-aortic balloon pumps, and two from dialysis catheters. There were nine other pseudoaneurysms: five brachial (two cardiac catheterization, two gunshot wounds, one after removal of an infected arteriovenous graft), one subclavian (central venous catheter insertion), one radial (arterial line), and one distal superficial femoral and one posterior tibial (both after blunt trauma). Twenty-nine pseudo-aneurysms were injected while on therapeutic anticoagulation. Patients underwent repeat ultrasound examination within 5 days and after 4 weeks.

RESULTS

Eighty-two of 83 pseudoaneurysms had initial successful treatment by this technique, including 28 of 29 in patients who were undergoing anticoagulation therapy. The only complication was thrombosis of a distal brachial artery, which resolved spontaneously. There were early recurrences in seven patients: four patients underwent successful reinjection; reinjection failed in two patients, who underwent surgical repair; and one patient had spontaneous thrombosis on follow-up. After 4 weeks, ultrasound examinations were completely normal or showed some residual hematoma, and there were no recurrent pseudoaneurysms.

CONCLUSION

Ultrasound-guided thrombin injection of pseudoaneurysms has excellent results, which support its widespread use as the primary treatment for this common problem.

Akt protein kinase inhibits Rac1-GTP binding through phosphorylation at serine 71 of Rac1

A putative Akt kinase phosphorylation site ((64)ydRIRplSYp(73)) was found in Rac1/CDC42 and Rho family proteins (RhoA, RhoB, RhoC, and RhoG). Phosphorylation of Rac1 by Akt kinase was assayed with recombinant Rac1 protein and the fluorescein-labeled Rac1 peptide. It was shown that the Rac1 peptide and the recombinant protein were phosphorylated by the activated recombinant Akt kinase and the lysate of SK-MEL28 cells, a human melanoma cell line. The phosphorylation of Rac1 inhibited its GTP-binding activity without any significant change in GTPase activity. Both the GTP-binding and GTPase activities of Rac1 S71A protein (with the serine residue to be phosphorylated replaced with alanine) were abolished regardless of the treatment of Akt kinase. Akt kinase activity and Rac1 peptide phosphorylation were down-regulated by the treatment of SK-MEL28 cells with wortmannin or LY294002 (a phosphoinositide 3-kinase inhibitor), but JNK/SAPK kinase activity was up-regulated. Thus, the results suggest that Akt kinase of the phosphoinositide 3-kinase signal transduction pathway phosphorylates serine 71 of Rac1 as one of its authentic substrates and modulates the Rac1 signal transduction pathway through phosphorylation.

A new class of COX-2 inhibitor, rutaecarpine from Evodia rutaecarpa

OBJECTIVE AND DESIGN

We investigated the effect of a new class of COX-2 inhibitor, rutaecarpine, on the production of PGD2 in bone marrow derived mast cells (BMMC) and PGE2 in COX-2 transfected HEK293 cells. Inflammation was induced by lambda-carrageenan in male Splague-Dawley (SD) rats.

MATERIAL

Rutaecarpine (8,13-Dihydroindolo[2',3':3,4]pyridol[2,1-b]quinazolin -5(7H)-one) was isolated from the fruits of Evodia rutaecarpa. BMMC were cultured with WEHI-3 conditioned medium. c-Kit ligand and IL-10 were obtained by their expression in baculovirus.

METHODS

The generation of PGD2 and PGE2 were determined by their assay kit. COX-1 and COX-2 protein and mRNA expression was determined by BMMC in the presence of KL, LPS and IL-10.

TREATMENT

Rutaecarpine and indomethacin dissolved in 0.1% carboxymethyl cellulose was administered intraperitoneally and, 1 h later, lambda-carrageenan solution was injected to right hind paw of rats. Paw volumes were measured using plethysmometer 5 h after lambda-carrageenan injection.

RESULTS

Rutaecarpine inhibited COX-2 and COX-1 dependent phases of PGD2 generation in BMMC in a concentration-dependent manner with an IC50 of 0.28 microM and 8.7 microM, respectively. It inhibited COX-2-dependent conversion of exogenous arachidonic acid to PGE2 in a dose-dependent manner by the COX-2-transfected HEK293 cells. However, rutaecarpine inhibited neither PLA2 and COX-1 activity nor COX-2 protein and mRNA expression up to the concentration of 30 microM in BMMC, indicating that rutaecarpine directly inhibited COX-2 activity. Furthermore, rutaecarpine showed in vivo anti-inflammatory activity on rat lambda-carrageenan induced paw edema by intraperitoneal administration.

CONCLUSION

Anti-inflammatory activity of Evodia rutaecarpa could be attributed at least in part by inhibition of COS-2.

Patterns and distribution of isolated calf deep vein thrombosis

PURPOSE

In the search for calf deep vein thrombosis (DVT) with color-flow duplex scanning (CFDS), most vascular laboratories investigate only the posterior tibial and peroneal veins. Few laboratories assess the soleal and gastrocnemial veins. This study was designed to determine the patterns and distribution of isolated calf DVT, including the soleal and gastrocnemial veins.

METHODS

In the last 3 years, 5250 patients (mean age, 66 +/- 15 years; range, 22 to 93 years) were referred to the vascular laboratory for clinical suspicion of DVT and underwent examination with CFDS. All superficial and deep named veins, excluding the anterior tibial from groin to ankle, were imaged. Of the deep veins in the calf, the peroneal, the posterior tibial, the gastrocnemial, and the soleal veins were examined throughout their length.

RESULTS

DVT was detected in 14% of the patients. Isolated calf DVT was detected in 282 limbs of 251 patients (4.8%). No significant difference was noted for the sex (114 men vs 137 women; P =.15) or the limb preference (145 left vs 137 right; P =.5). The peroneal veins were most frequently involved, with 115 limbs (41%) affected. The soleal veins were involved in 109 limbs (39%), followed by the posterior tibial in 105 limbs (37%) and the gastrocnemial in 79 limbs (29%). Thrombus in the soleal vein alone was found in 57 limbs (20%), in the gastrocnemial in 48 limbs (17%), in the peroneal in 41 limbs (15%), and in the posterior tibial vein in 35 limbs (12%). Thrombus confined to a single or paired vein was found in 181 limbs (64%). Thrombus involving two different veins (27%) was the second most frequent pattern, and thrombus in three (7%) or four (1.4%) different veins was less prevalent. Isolated thrombosis in veins not routinely investigated was found in 113 limbs (40%; soleal, n = 57; gastrocnemial, n = 48; soleal + gastrocnemial, n = 8). Multifocal origin of thrombosis, defined as thrombi in two different veins that do not anatomically communicate, was identified in 63 limbs (22%).

CONCLUSION

Forty percent of the patients with acute isolated calf DVT would be judged to have normal CFDS examination results if the muscular veins in the calf were not imaged. Multifocal origin of thrombosis was found in 22% of the involved limbs. The prevalence of thrombosis in any calf vein either alone or in combination is comparable. Accordingly, the soleal and gastrocnemial veins should be examined routinely.

Analysis of protein kinase C isoforms involved in the activation of laminin receptor in Raw264.7 macrophages

Adherence of hematopoietic macrophages to a laminin (LM) substratum requires protein kinase C (PKC)-dependent activation of LM receptor. This study was performed to analyze PKC isoform(s) leading to the activation of LM receptor during Raw264.7 macrophage-like cell adhesion to a LM substratum. Raw264.7 cells expressed multiple PKC isoforms, including alpha, beta I, delta, epsilon, zeta, lambda/iota, and mu. Among the PKC isoforms expressed, selective activation of PKC delta and epsilon was sufficient to induce cell adhesion to LM. PKC-dependent cell adherence was blocked by the selective inhibition of PKC delta, suggesting that PKC delta was the responsible PKC isoform leading to activation of LM receptor. PKC delta appeared to activate LM receptor in an intact microfilament-dependent pathway, because disruption of microfilament inhibited cell adhesion to LM without affecting PKC delta activation.

Higher prevalence of abdominal aortic aneurysms in patients with carotid stenosis but without diabetes

BACKGROUND

We compared abdominal aortic aneurysm (AAA) prevalence in 3 groups of patients at the Hines Veterans Affairs Medical Center: (1) patients with 50% or more carotid stenosis, (2) patients with less than 50% stenosis, and (3) patients screened for the Aneurysm Detection and Management (ADAM) study.

METHODS

Of all the patients referred to the vascular laboratory for carotid duplex examination during a 12-month period, patients with 50% or more carotid stenosis underwent ultrasonography of the abdominal aorta unless they had a previous scan or previous aortic surgery (group 1, n = 374). Patients with less than 50% carotid stenosis who had been screened for ADAM comprised group 2 (n = 139). They were compared with all patients screened for ADAM at our center during the same time period (group 3, n = 2477).

RESULTS

AAA of 3.0 cm or more were present in 18.2%, 12.2%, and 7.2% of groups 1, 2, and 3, respectively; AAA of 4.0 cm or more were present in 8.3%, 5.8%, and 2.1% of groups 1, 2, and 3, respectively. Among patients with carotid stenosis, those patients without diabetes accounted for the observed increase in prevalence (21.9 % > or = 3.0 cm and 10.2% > or = 4.0 cm vs 9.2% and 2.8% in patients with diabetes).

CONCLUSIONS

The relative risk of AAA is 2 to 3 times greater in patients with carotid stenosis compared with patients undergoing routine screening. However, only patients without diabetes account for the increased prevalence. Selective AAA screening of patients who are not diabetic with carotid stenosis is recommended.

Primary superficial vein reflux with competent saphenous trunk

OBJECTIVES

because reflux in superficial vein tributaries is most often collectively reported with the main saphenous veins, its importance remains largely unrecognised. This study was designed to identify the distribution and extent of non-truncal superficial venous reflux and its association with the signs and symptoms of chronic venous disease (CVD).

PATIENTS AND METHODS

eighty-four limbs in 62 patients with signs and symptoms of CVD and evidence of reflux on continuous-wave Doppler were subsequently examined with colour-flow duplex imaging. Incompetent superficial vein tributaries were imaged throughout their extent and both ends were identified. Limbs with reflux in the main trunk of the saphenous veins or the deep, perforator or muscular veins, superficial or deep vein thrombosis, injection sclerotherapy, varicose-vein surgery, arterial disease and inflammation of non-venous origin were excluded from the study. The CEAP classification system was used for staging clinical severity of CVD.

RESULTS

the prevalence of tributary reflux alone was 9.7% (84/860). Reflux was detected in 171 tributaries. The number of incompetent tributaries ranged from 1 to 5 per limb. Most prevalent were the tributaries to the greater saphenous (111, 65%<0. 0001), followed by those of lesser saphenous (33, 19%) or a combination of both (12, 7%). Incompetent non-saphenous tributaries were uncommon (15, 9%). Among the named tributaries in the lower limb the posterior arch vein was most often incompetent (46, 27%) followed by the anterolateral vein of the thigh (30, 18%), the medial accessory vein (16, 9%) and the anterior arch vein (14, 8%). Reflux in above-the-knee tributaries alone was found in 18 limbs (21%), in below the knee in 23 (28%) and in both sites in 43 (51%). The vast majority of the limbs (71%,p <0.0001) belonged to CVD class 2, 14% in class 3, 9% in class 1 and only 6% in class 4. Class 3 and 4 patients tended to have a longer duration of signs and symptoms, higher number of incompetent tributaries per limb and also a higher prevalence of combined above- and below-knee reflux.

CONCLUSIONS

these data indicate that reflux confined to superficial tributaries is found throughout the lower limb. Because this reflux is present without greater and lesser saphenous trunk, perforator and deep-vein incompetence or proximal obstruction, it shows that reflux can develop in any vein without an apparent feeding source. Greater saphenous tributaries are affected significantly more often than those of lesser saphenous, while non-saphenous reflux is uncommon. Most limbs have signs and symptoms of CVD class 2 and 15% belong in classes 3 and 4.

New insights into perforator vein incompetence

BACKGROUND

there has been much controversy on the role of perforator veins in the development of chronic venous disease (CVD). This study was designed to determine the duration and direction of flow of lower limb perforator veins (PVs) in relation to their location, diameter and competency status of superficial and deep veins, in healthy volunteers and patients with different grades of CVD.

PATIENTS AND METHODS

thirty limbs in 15 symptom-free volunteers and 103 limbs in 75 patients with signs and symptoms of CVD were examined with colour-flow duplex scanning. Superficial, perforator and deep veins were studied in the standing and sitting positions. Flow-velocity characteristics, the number and maximum PV diameter at the deep fascia and subfascially were determined. A PV was considered incompetent when the outward flow lasted >0.5 s.

RESULTS

581 PVs were found in the patients and 106 in the volunteers. 163 PVs (28%) were incompetent in the first group and none in the latter. The total number of PVs and the number of incompetent PVs per limb increased significantly with the severity of CVD. The mid-calf area had more competent and incompetent PVs in patients (p <0.01). Mean diameter of incompetent PVs in all the CVD classes was significantly larger than that of competent PVs. Competent PVs tended to be larger with increasing severity of CVD and they were significantly larger in the CVD classes 4 to 6 compared to controls (p <0.01). Subfascial PV diameter was markedly larger than that at the fascial level (p <0.001) regardless of the CVD class. A subfascial PV diameter of >3.9 mm (95% CI 3.4 to 4.4 mm) indicated incompetence. However, the reverse was not true, because about a third of incompetent PVs had a subfascial diameter of <3.9 mm. Both competent and incompetent PVs were smaller when located at the lower thigh, knee, ankle and anterior aspect of the calf than those found in the rest of the calf and mid-thigh (p =0. 03). Both inward and outward flow was found more often in patients than in controls (70/418 vs. 9/106, p =0.048). Most incompetent PVs had outward flow alone (126, 77%). PV incompetence was most frequently associated with reflux in superficial veins (120, 74% (p <0.0001), followed by reflux in both the superficial and deep veins (34, 21%) and reflux in the deep veins alone (9, 5%). The mean duration of outward flow was markedly longer in the presence of both superficial and deep vein reflux compared to superficial (p <0.001) or deep vein reflux alone (p <0.0001).

CONCLUSIONS

the number of incompetent PVs and the diameter of both competent and incompetent PV increases with the severity of CVD. Bidirectional PV flow is more common in patients than in normal volunteers, while 77% of the incompetent PVs have outward flow alone. PV incompetence is most often associated with reflux in the superficial veins, indicating that deep venous reflux is rarely the primary cause of PV insufficiency.

Localization of dopamine D1 and D2 receptor mRNAs in the rat systemic and pulmonary vasculatures

The present study was designed to evaluate the expression of dopamine D1 and D2 receptor mRNAs in systemic and pulmonary vasculatures. Using specific antisense riboprobes for dopamine D1 and D2 receptor cDNAs, in situ hybridization histochemistry was performed in the aorta, common carotid artery, vertebral artery, pulmonary artery, and superior vena cava of the adult male Sprague Dawley rat. In the case of the aorta, common carotid artery, and vertebral artery, dopamine D1 receptor mRNAs localized mainly in the smooth muscle cells of the tunica media. However, the signals of dopamine D2 receptor mRNAs were found in the endothelium and subendothelial layer of tunica intima, and interstitial cells of tunica adventitia. In the case of the pulmonary artery, signals of dopamine D1 receptor mRNAs were detected within the tunica intima, media, and adventitia. Expression of D2 receptor mRNAs was detected in the walls of small blood vessels within the tunica adventitia of the pulmonary artery. There were no detectable signals of dopamine D1 and D2 receptor mRNAs in the vein. The uneven distribution of dopamine D1 and D2 receptor mRNAs in the rat systemic vasculatures and pulmonary artery suggests that dopamine differentially regulates the vasodilation of the systemic and pulmonary arteries through the differential stimulation of dopamine D1 and D2 receptor.

Isolation of a new cerebroside from the root bark of aralia elata

A new cerebroside, named Aralia cerebroside (1), was isolated from the root bark of Aralia elata. The structure of 1 was determined to be 1-O-beta-D-glucopyranosyl-(2S,3S,4R, 8E)-2-[(2'R)-2'-hydroxypalmitoylamino]-8-octadecene-1,3,4-triol on the basis of physicochemical and spectroscopic studies.

Inhibition of mouse ear edema by steroidal and triterpenoid saponins

Certain steroids and triterpenoids isolated from diverse plant families were known to possess anti-inflammatory activity. In the course of finding new anti-inflammatory natural products, some steroidal and triterpenoid saponins were isolated and evaluated for their anti-inflammatory activity using in vivo mouse ear edema test. At the oral dose of 100 mg/kg, several steroidal saponins and triterpenoid saponins such as hederagenin glycosides showed significant inhibition of ear edema (20-37% inhibition), though less potent than indomethacin and hydrocortisone.

Inhibition of rat adjuvant-induced arthritis by ginkgetin, a biflavone from ginkgo biloba leaves

Ginkgetin, a biflavone isolated from Ginkgo biloba leaves, was previously reported as an inhibitor of group II phospholipase A2. In this study, ginkgetin was evaluated for in vivo antiarthritic and analgesic activities. Ginkgetin (10-20 mg/kg/day) strongly reduced arthritic inflammation in an animal model of rat adjuvant-induced arthritis (86% inhibition at 16 days at a dose of 20 mg/kg/day) via intraperitoneal injection, while prednisolone (5 mg/kg/day) showed 79% reduction. Histological examination of the knee joints confirmed our findings. When analgesic activity was measured, ginkgetin showed a dose-dependent inhibition in an animal model of acetic acid-induced writhing. ED50 values for ginkgetin and indomethacin were 8.9 and 3.8 mg/kg, respectively. All these results indicate that ginkgetin may be a potential antiarthritic agent having analgesic activity.

Akt protein kinase enhances human telomerase activity through phosphorylation of telomerase reverse transcriptase subunit

With the amino acid sequences of all reported Akt kinase physiological substrates, the possible Akt kinase substrate specificity has been suggested. The serine/threonine residue to be phosphorylated in these proteins is placed within stretches of amino acids with homology, and the arginine residues on the -5 and -3 positions and a hydrophobic amino acid on the +2 position are conserved relative to those of serine/threonine residues (XXRXRXXS/TXX). We noticed two putative Akt kinase phosphorylation sites (220GARRRGGSAS229) and (817AVRIRGKSYV826) in human telomerase reverse transcriptase (hTERT) subunit. To demonstrate that hTERT is an Akt kinase substrate protein, we performed the nonradioactive protein kinase assay with the fluorescein hTERT peptide (817AVRIRGKSYV826). We observed the phosphorylation of hTERT peptide by the human melanoma cell lysate or the activated recombinant Akt kinase proteins in vitro. With the treatment of the growth factor deprivation or okadaic acid, we also observed the up-regulation of both hTERT peptide phosphorylation and the telomerase activity. We noticed that Wortmannin down-regulates hTERT peptide phosphorylation and telomerase activity together. In addition, we observed the enhancement of telomerase activity with the pretreatment of Akt kinase in vitro. Thus, these observations suggest that Akt kinase enhances human telomerase activity through phosphorylation of hTERT subunit as one of its substrate proteins.

Timing and frequency of perioperative carotid color-flow duplex scanning: A preliminary report

PURPOSE

The results of intraoperative and early postoperative carotid color-flow duplex scanning (CFS) after endarterectomy were reviewed to determine whether any perioperative studies could be eliminated.

METHODS

Patients undergoing carotid endarterectomy with intraoperative CFS between 1986 and 1997 were identified. Early postoperative CFS was performed between 1 day and 3 weeks postoperatively, then it was performed again at 6 months postoperatively.

RESULTS

During the study period, 560 patients, 325 men and 235 women, underwent 621 carotid endarterectomies. A satisfactory intraoperative carotid CFS was completed in 611 (98.4%) patients. There were 20 (3.2%) vessels with a major defect that required revision for fronds or flaps (n = 11), retained atheroma (n = 5), low flow (n = 2), high velocity or turbulence (n = 1), or dissection (n = 1). Another 146 vessels (23.5%) had minor defects, such as retained proximal atheromas or small (less than 3 mm) fronds, but were not revised. The remaining 445 vessels were normal. The first postoperative CFS was normal in all the revised carotids and in 138 (94.5%) vessels with minor intraoperative defects. At 6 months, recurrent stenosis (more than 75% area reduction) was identified in 1 of 18 revised carotids (5.5%), 4 of 138 vessels (2. 9%) with minor defects, and 17 of 406 vessels (4.2%) that were normal intraoperatively. The incidence of recurrent stenosis was not significantly different in the three groups (P =.7).

CONCLUSION

Intraoperative CFS is useful because major unsuspected defects can be corrected immediately, thus avoiding potential neurologic morbidity. However, the postoperative day 1 CFS can be eliminated in most cases, because it does not provide any relevant clinical information.