Electron nanoprobe induced oxidation: a simulation of direct-write purification.

Electron beam direct-write has recently taken a large step forward with the advent of methods to purify deposits. This development has opened the door for future direct-write device prototyping and editing. In one such approach, an additional beam scanning procedure removes carbonaceous impurities via oxidation from metal-carbon deposits (e.g., PtC5) in the presence of H2O or O2 after deposition. So far, critical aspects of the oxidation reaction remain unclear; experiments reveal clearly that electron stimulated oxidation drives the process yet it is not understood why H2O purifies by a bottom-up mechanism while O2 purifies from the top-down. The simulation results presented here suggest that the chemisorption of dissolved O2 at buried Pt nanoparticle surfaces controls purification in the top-down case while both the high relative solubility coupled with weak physisorption of H2O explains the bottom-up process. Crucial too is the role that the carbonaceous contaminant itself has on the dissolution and diffusion of O2 and H2O. These results pave the way for simulation driven experiments where (1) the transient densification of the deposit can be accounted for in the initial deposit design stage and (2) the deposition and purification steps can be combined.

Current strategies and possible perspectives of ultrasonic risk stratification of ischemic stroke in internal carotid artery disease.

Atherosclerotic alterations of the internal carotid artery frequently result in ischemic stroke. However, it remains unclear which specific factor mainly causes an increased risk of stroke. Constant improvements of the diagnostic possibilities of ultrasonic examinations provide increasingly profound insight into plaque alterations. If "risk plaque" could be reliably identified, the therapeutic decision for either medical or surgical treatment could be made more rationally. In this review, we summarize current developments in the ultrasound imaging of atherosclerotic changes in carotid artery disease with special emphasis on technical aspects and the rationale of contrast imaging of plaque vascularization. Methodological limitations and possible future applications are discussed.

Oestradiol levels in varicose vein blood of patients with and without pelvic vein incompetence (PVI): diagnostic implications.

PURPOSE: To assess the difference in the oestradiol levels of blood taken from varicose veins in patients with and without pelvic vein incompetence (PVI). MATERIALS AND METHODS: Women of child-bearing age with symptomatic primary or recurrent varicose veins of the great saphenous vein (GSV) were included in a prospective study. Patients underwent duplex ultrasonography and pelvic vein phlebography. They were divided into a group with PVI (PVI group) and a control group with GSV reflux alone (VV group). Blood samples were collected from the GSV at the sapheno-femoral junction or lower in the thigh as well as from the arm. Oestradiol levels were determined by electroluminescence. RESULTS: Between January and December 2007, 40 women were studied, of which 19 showed phlebographic evidence of PVI (PVI group), while 21 were included in the VV group. Phlebography revealed an incompetent ovarian vein in 14 (74%) patients of the PVI group, dilated uterine and ovarian plexuses in 12 (63%) and an incompetent internal iliac vein in six cases (32%). In the PVI group, the median oestradiol level in GSV samples was 121 pgml(-1) (range: 12-4300), while in the VV group the median level was 75 pgml(-1) (range: 9-1177). In the upper limb, the PVI group patients had a median level of 78 pgml(-1) (range: 15-121) and the VV group patients 68 pgml(-1) (range: 13-568). The ratio of lower limb/upper extremity was significantly higher (p<0.002) in patients of PVI group (median: 1.9; range: 0.7-33) than in those of the VV group (median: 1.1; range: 0.8-13). A threshold ratio of 1.4 showed the highest combined sensitivity and specificity in differentiating patients with PVI from those without. CONCLUSIONS: In patients with varicose veins arising from the GSV, oestradiol levels were significantly higher in the lower limb than in the upper extremity in the subgroup with associated PVI. It may be possible to use this observation as a diagnostic test in patients with suspected PVI. This deserves further study.

Long-term results after transfemoral venous thrombectomy for iliofemoral deep venous thrombosis.

OBJECTIVE: In patients presenting with extensive venous thrombosis affecting the pelvic veins, transfemoral venous thrombectomy has been suggested as an effective treatment in selected patients. We present our experience of this technique as well as its long-term results. PATIENTS AND METHODS: Between January 1998 and January 2008, a total of 83 patients underwent transfemoral venous thrombectomy in our Department of Vascular Surgery. In 22 cases, this was combined with angioplasty and stenting of an iliac vein stenosis. Isolated intra-operative thrombolysis was performed in eight cases to treat deep venous thrombosis (DVT) affecting veins distal to the common femoral vein. All patients suffered from a DVT involving the pelvic veins. A DVT involving all venous segments from the pelvis to the calf was present in 63% of cases. Patients were followed up at 3 months, 6 months and yearly thereafter by clinical and duplex ultrasound examination. RESULTS: In all patients, the procedure was successful in achieving re-canalisation of the pelvic veins at the end of the operation. Perioperatively, there was no mortality and there was no case of clinically detected pulmonary embolism. Life-table analysis showed that, after a mean duration of 60 months following treatment, approximately 75% of the treated venous segments remained patent. Moderate post-thrombotic syndrome (PTS; clinical severity, etiology, anatomy and pathophysiology (CEAP) C2-C4) was present in 20% of cases; severe PTS (CEAP C5 and C6) did not occur in any of the treated patients. CONCLUSIONS: It is safe and effective to treat extensive iliofemoral DVT using transfemoral venous thrombectomy and this prevents the development of severe PTS in the long term. The procedure is only feasible in a subset of patients with DVT, depending on the extent and the age of the thrombosis.

Pelvic venous incompetence: reflux patterns and treatment results.

OBJECTIVE: To assess reflux patterns and the results of endovascular obliteration of ovarian veins in patients with symptomatic pelvic venous incompetence (PVI). METHODS: A total of 71 female patients (mean age 49 years) with signs of PVI on selective phlebography of the pelvic veins were included in the study. In 53 cases (75%), recurrent varicose veins following previous surgery and stripping of the great saphenous vein were present and 51 patients (72%) were multiparous (> or = 2 children). Symptoms were scored on a visual analogue scale (VAS) assessing pelvic and lower limb pain. After duplex ultrasonography of the lower limb veins, in cases of suspected PVI, the presence of any reflux in the ovarian and pelvic veins was demonstrated by phlebography. In selected cases, endovascular treatment with embolisation was used. Follow-up assessment of symptoms was carried out at 1, 2 and 3 years. RESULTS: The left ovarian vein (OV) and the right internal iliac vein (IIV) were most frequently affected by reflux (n=41, 58% each). In about half the number of patients, reflux was demonstrated in more than one of the main pelvic veins (n=38, 54%). An extension of reflux into varicose veins of the groin or lower limb was demonstrated in 44 patients (62%); 35 patients (49%) received treatment for their PVI by coil embolisation. Fifty-five patients (77%) completed follow-up. Patients with isolated ovarian vein incompetence, who were treated by embolisation, experienced a significant improvement of symptoms (mean symptom score 5.2 standard deviation (SD) 3.5 before and 1.2 SD 0.9 after embolisation treatment; p<0.0001), while patients with untreated incompetence did not show improvement in symptoms (mean score 4.5 SD 1.6 before and 5.1 SD 1.5 after conservative treatment; non-significant (N.S.)). Improved symptoms were detected in patients with isolated IIV incompetence, who underwent embolisation treatment (mean symptom score 5.1 SD 2.5 before and 2.1 SD 1.6 after treatment; N.S.) although this did not reach statistical significance. Conservative treatment of patients with isolated IIV incompetence resulted in no relevant changes (mean score 4.2 SD 2.0 before and 4.5 SD 2.1 after treatment; N.S.). Worsening of symptoms was found in patients with combined reflux who underwent conservative treatment (mean score 5.3 SD 2.0 before and 6.5 SD 2.5 after treatment, N.S.). In case of combined OV and IIV reflux, isolated interventional treatment of incompetent ovarian veins did not improve symptoms at each interval of the follow-up (mean score 5.2 SD 2.1 before and 5.1 SD 2.6 after treatment, N.S.), while coiling of all reflux pathways resulted in symptom reduction; but this did not reach statistical significance due to the small numbers of patients (mean score 5.6 SD 2.2 before and 3.2 SD 2.1 after treatment, N.S.). CONCLUSIONS: Combined reflux in more than one pelvic vein is common. In these cases, isolated treatment of ovarian veins or conservative treatment is associated with a poor midterm clinical outcome. A clinical improvement was achieved only in patients with isolated ovarian vein incompetence.

Salvage of a dialysis angioaccess by bypassing a central venous obstruction to the common femoral vein.

We describe the case of a 71 year-old male patient undergoing haemodialysis who presented with severe symptoms of venous hypertension at the left upper extremity due to subclavian and innominate vein obstruction. The patient had a well functioning ispilateral angioaccess. The pain and disabling swelling of the upper extremity developed 12 months after having a radio-cephalic arteriovenous fistula performed and progressively worsened in the last two months. The patient underwent extraanatomic axillo-femoral venous bypass grafting with a 8 mm polytetrafluoroethylene graft to the ispilateral common femoral vein. The postoperative recovery was regular and the patient was discharged 6 days after surgery with a functioning bypass and relief from the venous hypertension symptoms. In this case, surgical bypassing of a central venous obstruction through an extra-anatomical pathway relieved the symptoms of venous hypertension and prolonged the use of the haemodialysis access.

MR venography in the detection of pelvic venous congestion.

PURPOSE: To investigate the feasibility of using magnetic resonance venography (MRV) to detect pelvic venous congestion (PVC). METHODS: A prospective study of 23 female patients with signs and symptoms of PVC, who underwent duplex sonography, MRV and phlebography (P). Examinations were interpreted in a blinded fashion. Visualization of venous anatomy, presence of venous incompetence and congestion grade were evaluated. Sensitivity and specificity of MRV using P as reference were calculated. RESULTS: MRV agreed with P in 96% (Cohen-K-value 0.646) and in 70% (K 0.555) of the cases respectively in the venous anatomy and congestion grade. Sensitivity and specificity of MRV were 88% and 67% for ovarian veins, 100% and 38% for hypogastric veins and 91% and 42% for the pelvic plexus. CONCLUSIONS: In this prospective study MRV showed high sensitivity in the evaluation of patients with suspected PVC. Routine use of this diagnostic method requires further studies in larger patient cohorts.

Residual stumps associated with inguinal varicose vein recurrences: a multicenter study.

PURPOSE: It is unclear whether a residual sapheno-femoral stump left in place after stripping of the great saphenous vein can contribute to the formation of late inguinal varicose vein recurrence. In order to obtain information about the time course of recurrence development, patients with histologically proven residual stumps were recruited and asked about the interval between the initial operation and the first clinical signs of varicose vein recurrence. METHODS: A multi-centre study involving 7 centres was conducted amongst patients undergoing redo-surgery for inguinal varicose vein recurrences. The sapheno-femoral stumps resected during the redo-surgery were classified histologically. Patients with a proven long residual sapheno-femoral stump were asked to describe the first signs of varicose vein recurrence with the help of a standardised questionnaire. From these data the symptom-free interval, consisting of the time frame between the initial operation and the first signs of recurrence, was determined. RESULTS: In 279 legs of 251 patients a long residual sapheno-femoral stump was present. Most patients had experienced a symptom-free interval after the initial operation with a mean duration of 7.4 S.D. 5.5 years. Recurrent varicose veins became apparent after a mean time interval of 6.3 S.D. 5.3 years and congestion symptoms occurred after a mean interval of 8.5 S.D. 5.7 years. CONCLUSIONS: In patients with symptomatic groin recurrences, a long residual sapheno-femoral stump was found in about two thirds of cases. The first clinical signs of varicose vein recurrence can be expected 7-8 years after the initial treatment at the earliest. Long term follow up is required reliably to asses the outcome of treatment for varicose veins.

Acute iliofemoral deep venous thrombosis due to giant ovarian tumor: report of a hybrid treatment.

Ovarian tumors rarely cause acute iliofemoral thrombosis due to direct compression. This case represents an example of successful therapy using an interdisciplinary approach. A 37-year-old woman was admitted with a painful swelling of the left lower limb. Computed tomography revealed a giant abdominal mass originating from the left ovary producing a thrombotic occlusion of the left iliofemoral veins. Surgical treatment consisted of complete tumor removal, adnexectomy and appendectomy. During the same operation, transfemoral thrombectomy and stent implantation in the iliac vein were performed, followed by creation of an arteriovenous fistula in the left groin. Hystologic examination revealed a well-differentiated mucinous ovarian adenocarcinoma. The patient recovered well and is tumor-free 6 months after surgery. The deep venous system is still patent at follow-up. In this case, minimal surgical trauma and complete tumor as well as thrombus removal succeeded through a positive complementary interdisciplinary approach.

Deep venous thrombosis in a patient with large uterine myomata. Case report.

A 42-year-old woman was admitted with a painful swelling of the left lower limb. Computed tomography revealed an inhomogenous uterine enlargement due to multiple myomata producing a thrombotic occlusion of the left iliac veins. Surgical treatment consisted of isolated hysterectomy. During the same operation, transfemoral thrombectomy and stent implantation in the iliac vein were performed. Hysto-logic examination revealed numerous leiomyomata as well as an endometriosis. The patient recovered well and is pain-free six months after surgery. The deep venous system is still patent at follow-up. Uterine myomata rarely cause acute iliac vein thrombosis due to direct compression. This case represents an example of successful therapy using an interdisciplinary approach.

Is initial success of thrombolytic therapy with rt-PA in patients with lower limb ischemia durable? A long-term follow-up series.

BACKGROUND: Catheter-directed intraarterial thrombolytic therapy with rt-PA has been established as an alternative to surgery in selected patients with lower limb ischemia. The purpose of this study is to evaluate its long-term results and to try to identify patient variables influencing outcome. PATIENTS AND METHODS: The results of thrombolytic treatment for acute or subacute lower limb ischemia in 82 patients (51 male, 31 female) were retrospectively analysed. Clinical data (time of symptoms onset, clinical stage, type of affected vessel, anatomical localisation) as well as comorbidities were recorded. The success rate of thrombolysis as well as the incidence of adverse events was evaluated. Patients with initial success were followed up after a median of 52,5 months. RESULTS: Thrombolytic therapy was successful in 67 cases (82%). An additional endovascular or surgical procedure was necessary in 39 of these patients (48%). The overall bleeding rate was 18% and the mortality and major amputation rate was 1%. 42 patients with early clinical success were available for follow-up. 34 of them (81%) were free of ischemic symptoms and the overall limb salvage rate was 96%. We could not identify factors significantly influencing early or long-term results, although there was a trend towards better results in patients with acute ischemia and in patients with occluded native arteries. CONCLUSIONS: Intraarterial local thrombolytic therapy has a relatively high initial success rate in selected patients with lower limb ischemia, but is associated with a significant number of bleeding complications. Furthermore, additional procedures are required in almost half the patients. Initial success is durable at the long-term in the majority of cases. Better selection of patients and refinements of the thrombolytic therapy might help to further improve results and lower the bleeding complications.

Distal revascularization-interval ligation for the treatment of angioaccess-induced ischemia. Case report.

Two cases of upper extremity ischemia due to a steal phenomenon occurring after the creation of an arterio-venous fistula (AVF) for hemodialysis access are described. A successful treatment with a brachial to brachial artery vein bypass and a ligation of the artery distal to the AVF origin (DRIL-Procedure) was performed in both cases. Complete disappearance of symptoms and healing of the ischemic lesions with maintaining of the angioaccess patency 6 months after the repair reveal that this procedure corrected the stealing.

The effect of mercuric salts on the electro-rotation of yeast cells and comparison with a theoretical model.

The rotational spectrum of yeast cells changed after pre-treatment of the cells with HgCl2 or Hg(NO3)2 and became indistinguishable from that of ultrasonically produced cell walls. The spectrum of the affected cells contained a peak which could only be explained by attributing a conductivity to the cell walls that was higher than that of the medium. Theoretical models of the rotational response are fully in accord with the experimental spectra. It is shown that the rotation method is capable of measuring even the low cell wall conductivity of yeast cells (which was found to be 33 microS/cm at 10 microS/cm medium conductivity). Knowledge of the spectra allowed a field frequency to be selected at which untreated cells showed no rotation, but at which cells affected by treatment with Hg(II) identified themselves by rotating in the same direction as the field. Calculation of the percentage of cells showing this co-field rotation gave an index (termed the co-field rotation value) of the proportion of the cells that were affected. Using this technique, effects of 25 nmol/l Hg(II) could be demonstrated. In media of low conductivity (10 microS/cm) the change in the rotational spectrum was usually 'all-or-none', whereas at 200 microS/cm a graded Hg(II)-mediated change became apparent. The co-field rotation method showed that the action of small quantities of Hg(II) was still increasing after 3 h of incubation and paralleled the Hg(II)-induced K+ release. A rapid reduction of the effects of Hg(II) was seen when 3-30 mM K+ (or Na+) or when 1 mM Ca2+ were present in the incubation medium, or as the pH was increased. At high incubation cell concentrations the toxic effect of Hg(II) was reduced, apparently due to binding by the cells.

Laparoscopic thrombendarterectomy of the infrarenal aorta.

The aim was to perform a totally laparoscopic thrombendarterectomy (TEA) of the infrarenal aorta to reduce the trauma connected to the surgical approach. A 52-year-old man was referred to our institution with severe claudication. Angiography revealed a subtotal stenosis of the infrarenal aorta. Because the lesion was not suitable for an interventional procedure, a TEA was planned. The surgery was performed through six ports using a transperitoneal approach with pneumoperitoneum. The laparoscopic TEA was carried out according to the standards of open vascular surgery. The surgery time was 285 minutes, the crossclamping lasted 105 minutes, and the blood loss was 100 mL. The angiographic and functional results were excellent. The patient experienced a rapid recovery and was discharged after 6 days. This case report shows the feasibility of totally laparoscopic TEA of the infrarenal aorta. The well-known advantages of minimally invasive techniques in abdominal surgery with regard to the decrease of surgical trauma may also be valid in aortic surgery for occlusive disease.

[Attempt at preventive treatment of esophagitis caused by intubation during intensive care]. / Tentative de traitement préventif des oesophagites sur sonde en réanimation.

A randomized prospective trial was designed to evaluate the preventive treatment of esophagitis in 31 intensive care patients who had a nasogastric feeding tube for at least 10 days. Fourteen patients (group B) received no preventive treatment while 17 patients (group A) received 300 mg of cimetidine every 6 h intravenously and 11 g of colloidal aluminium phosphate every 4 h per os. All patients were fed a standard diet through their nasogastric tube at a constant rate of 30 Kcal/kg/day. Endoscopic controls at day 1 and 10 showed that the number of initial and final esophagitis was not different in groups B and A: 7 and 8 at day 1, 11 and 10 at day 10, respectively. The inefficiency of this preventive treatment suggested that acid gastroesophageal reflux is not a major factor in the occurrence of nasogastric feeding tube-induced esophagitis. However as esophagitis is associated with a more severe Knaus index and a greater number of gastric stress ulcer risk factors, it is suggested that decreased defense of the mucosa may be a key factor in the occurrence of this type of esophagitis.

[Pancreatic sarcoidosis]. / Sarcoïdose pancréatique.

The authors report the case of a 30 year-old man with previous history of sarcoidosis, who presented with a painful infiltration of the pancreas. A review of the literature showed that symptomatic pancreatic sarcoidosis was uncommon, since only 8 other cases have been reported. Pancreatic involvement is frequently associated with hepatic infiltration (5/6 cases). Exocrine or endocrine dysfunction are possible. Diagnosis is made only at exploratory laparotomy. Prognosis is good. Steroid therapy is indicated in this peculiar type of pancreatitis, because of its long-range effectiveness on the outcome of the disease.

Pelvic vein incompetence influences pain levels in patients with lower limb varicosity.

PURPOSE: To detect the influence of pelvic vein incompetence (PVI) on pain levels in patients with varicosity of the lower limb. MATERIALS AND METHODS: Women of child-bearing age with symptomatic primary or recurrent varicosity of the greater saphenous vein (GSV) were prospectively included in two groups depending on the presence or absence of phlebographic signs of PVI. Pain assessment was carried out with the help of a visual analogue scale (VAS). RESULTS: Forty women were included in the study. Nineteen of them had phlebographic evidence of PVI (group A), whereas 21 were included in the control group (group B). Patients of group A reported a higher median total pain level than patients of group B (group A median 62, range 25-100; group B median 32, range 0-100; P = 0.001). In group A, patients experienced a median level of pain of 67.2 at the lower limb in the standing position (range 40-100) versus a median of 50.3 (range 36-81) in patients of group B (P = NS). The median level of leg pain in the sitting position was 41.2 (range 0-67) in patients of group A and 38.1 (range 0-46) in women of group B (P = NS). Pelvic pain level in the standing position was higher (P = NS) in patients of group A (median 72.2, range 50-91), than in women of group B (median 20.1, range 0-41). In patients of group A, statistically significant (P = 0.0001) higher VAS scores for pelvic pain level in sitting (group = A median 67.2, range 59-71; group B median 18.1 range 0-35) were reported. CONCLUSIONS: In a small population of patients with GSV varicosity, overall pain levels were significantly higher in a subgroup of patients with phlebographic signs of PVI. This finding suggests that the presence of PVI might influence the intensity of varicosity symptoms.