Value of Color Flow Duplex Imaging in Detection of Subtotal and Total Internal Carotid Artery Occlusion

The aim of this retrospective study was to estimate the predictive value of color flow duplex imaging (CFDI) in the detection of near-total and total internal carotid artery (ICA) occlusion. The authors reviewed all diagnoses of 95-99% ICA stenosis and ICA occlusion made by CFDI from 1991 to 1994 at St. Mary's Hospital. One hundred thirtyseven patients with CFDI diagnosis of ICA occlusion and 42 with 95-99% stenosis had also been subjected to intraarterial digital substraction angiography during the same period and within one month from the CFDI. They compared the results of both methods to estimate the positive predictive value (PPV) of CDFI in the detection of ICA occlusion and 95-99% stenosis. Furthermore, they compared the PPV of CDFI diagnoses during 1991-1993 with that of 1994 for the same spectrum of ICA disease.

CFDI had 96% PPV in the diagnosis of carotid occlusion (95% confidence interval, 94-97.9%, false-positive rate 3.6%) and 83% in the diagnosis of 95-99% stenosis (95% confidence interval 63.4-88.9%, false-positive rate 17%). Although there was improvement of CFDI's ability in the diagnosis of occlusion during 1994 in comparison with the 1991-1993 period, this was not statistically significant (PPV 95.9% and 97.4% respectively).

CFDI may slightly underestimate or overestimate the degree of tight ICA stenosis. However, in the diagnosis of ICA occlusion CFDI is highly reliable.

Caval migration of a ureteral J-stent after simultaneous ureter and iliac vein perforation during its placement for obstructive pyelonephritis

A variety of indications have made the use of double pigtail ureteral catheters routine in urological practice. Although side effects are frequent they are usually mild. We report a case of intravenous stent migration after simultaneous perforation of the left ureter and left common iliac vein during retrograde J-stent placement. To the authors' knowledge such a potentially severe complication of a J-stent has not been previously described. A postprocedural plain abdominal radiograph is a helpful tool which may suggest possible misplacement of the pigtail stent especially if urine fails to return from the distal opening and, if verified, advocate immediate intervention in order to avoid any further devastating complications.

A multi-biosensor based on immobilized Photosystem II on screen-printed electrodes for the detection of herbicides in river water

A multi-biosensor for detection of herbicides and pollutants was constructed using various photosynthetic preparations as biosensing elements. The photosynthetic thylakoid from Spinacia oleracea L., Senecio vulgaris and its mutant resistant to atrazine were immobilized with (BSA-GA) on the surface of screen-printed sensors composed of a graphite-working electrode and Ag/AgCl reference electrode deposited on a polymeric substrate. The biosensor was composed of four flow cells with independent illumination of 650 nm to activate electron transfer in Photosystem II. The principle of the detection was based on the fact that herbicides selectively block electron transport activity in a concentration-dependent manner and that the four PSII biomediators show differential recognition activity toward herbicides. Changes of the activity were registered amperometrically as rate of photoreduction of the artificial electron acceptor DQ. The setup resulted in a reusable herbicide multibiosensor with a good stability (half-life of 16.7 h for spinach thylakoids) and limit of detection of about 10(-8) M for herbicides recovered in spring in river.

Recurrent varicose veins after surgery: a new appraisal of a common and complex problem in vascular surgery

OBJECTIVE

To assess the true incidence, the reflux patterns and the mechanisms responsible for recurrent varicose vein disease according to current definitions and guidelines.

PATIENTS AND METHODS

Ninety-three patients (69 female, 24 male, mean age: 48 years) were prospectively evaluated pre- and postoperatively (1 month and 5 years), using clinical and colour duplex examination of both lower limbs. The CEAP score and its modification for recurrence (REVAS) were used for classification.

RESULTS

In 113 operated lower limbs, 28 (25%) were found to have a recurrence, 20 of which were symptomatic (20/28, 72%). However, in this group, the mean severity score decreased significantly from 6.5 (SD 3.1) to 5.2 (SD 2.8) (p<0.001, paired t-test). The correlation between the type and cause of recurrence revealed: (1) true recurrent varices in eight limbs (8/28, 29%), primarily caused by neovascularisation, (2) new varicose veins as a consequence of disease progression in seven limbs (7/28, 25%), (3) residual veins in three limbs (3/28, 11%) mainly due to tactical errors (e.g. failure to strip the GSV), (4) complex patterns in 10 limbs (10/28, 36%). In the limbs with recurrence, 42 sources of venous reflux were identified: (1) 19 new sites of venous reflux were due to disease progression (15% of the operated limbs), (2) 13 were caused by neovascularisation (11.5% of the operated limbs), (3) six resulted from tactical failures (5.3% of the operated limbs) and (4) four were due to technical failures (3.5% of the operated limbs).

CONCLUSIONS

This study shows that the recurrence of varicose veins after surgery is not uncommon. However, the clinical condition of most affected limbs remains improved. Progression of the disease and neovascularisation are responsible for more than half of the recurrences. Rigorous evaluation of patients and assiduous surgical technique might reduce recurrence due to technical and tactical failures.

Patterns of venous reflux in limbs with venous ulcers. Implications for treatment

AIM

To investigate the anatomic distribution of vein reflux in limbs with healed or active ulcers (CEAP V and VI).

METHODS

Sixty limbs (58 patients) belonging to CEAP classes V and VI were identified from 798 limbs (519 patients) with ultrasonically proven chronic venous insufficiency (CVI). Age, gender, duration of the venous ulcer, and history of deep venous thrombosis were correlated to the anatomic distribution of the venous reflux.

RESULTS

The prevalence of active or healed ulcers in limbs with CVI was 7.5%. Among 60 limbs with ulcers, primary CVI was present in 34 (56.7%) and post-thrombotic CVI in 26 limbs (43.3%). No difference in age and gender was found between the 2 groups (p=0.2 and p=0.8, respectively). However, the duration of the ulcer was longer in limbs with post-thrombotic CVI (p<0.05). The prevalence of perforator reflux was 41.2% (14/34) in limbs with primary CVI and 38.5% (10/26) in limbs with post-thrombotic CVI (p=0.8). Superficial venous insufficiency, with or without perforating vein reflux, was the commonest pattern in limbs with primary CVI; it was rare in limbs with post-thrombotic CVI (22/34 or 64.7% vs 2/26 or 7.7%, p<0.01). Deep vein insufficiency was present in 35.3% (12/34) of the limbs with primary CVI and in 92.3% (24/26) of the limbs with post-thrombotic CVI (p<0.01).

CONCLUSION

Superficial venous insufficiency, with or without perforating vein reflux, was the commonest pattern in limbs with primary CVI, whereas, deep venous insufficiency was present in most of the limbs with post-thrombotic CVI. The prevalence of perforating vein reflux was comparable in both settings. Thus, elimination of superficial reflux is expected to result in ulcer healing of most limbs with primary CVI, whereas, the value of such treatment in post-thrombotic limbs is not clear.

The mechanism of UV-A radiation-induced inhibition of photosystem II electron transport studied by EPR and chlorophyll fluorescence

The UV-A (320-400 nm) component of sunlight is a significant damaging factor of plant photosynthesis, which targets the photosystem II complex. Here we performed a detailed characterization of UV-A-induced damage in photosystem II membrane particles using EPR spectroscopy and chlorophyll fluorescence measurements. UV-A irradiation results in the rapid inhibition of oxygen evolution accompanied by the loss of the multiline EPR signal from the S(2) state of the water-oxidizing complex. Gradual decrease of EPR signals arising from the Q(A)(-)Fe(2+) acceptor complex, Tyr-D degrees, and the ferricyanide-induced oxidation of the non-heme Fe(2+) to Fe(3+) is also observed, but at a significantly slower rate than the inhibition of oxygen evolution and of the multiline signal. The amplitude of Signal II(fast), arising from Tyr-Z degrees in the absence of fast electron donation from the Mn cluster, was gradually increased during the course of UV-A treatment. However, the amount of functional Tyr-Z decreased to a similar extent as Tyr-D as shown by the loss of amplitude of Signal II(fast) that could be measured in the UV-A-treated particles after Tris washing. UV-A irradiation also affects the relaxation of flash-induced variable chlorophyll fluorescence. The amplitudes of the fast (600 micros) and slow (2 s) decaying components, assigned to reoxidation of Q(A)(-) by Q(B) and by recombination of (Q(A)Q(B))(-) with donor side components, respectively, decrease in favor of the 15-20 ms component, which reflects PQ binding to the Q(B) site. In the presence of DCMU, the fluorescence relaxation is dominated by a 1 s component due to recombination of Q(A)(-) with the S(2) state. After UV-A radiation, this is partially replaced by a much faster component (30-70 ms) arising from recombination of Q(A)(-) with a stabilized intermediate PSII donor, most likely Tyr-Z degrees. It is concluded that the primary damage site of UV-A irradiation is the catalytic manganese cluster of the water-oxidizing complex, where electron transfer to Tyr-Z degrees and P(680)(+) becomes inhibited. Modification and/or inactivation of the redox-active tyrosines and the Q(A)Fe(2+) acceptor complex are subsequent events. This damaging mechanism is very similar to that induced by the shorter wavelength UV-B (280-320) radiation, but different from that induced by the longer wavelength photosynthetically active light (400-700 nm).

The mechanism of UV-A radiation-induced inhibition of photosystem II electron transport studied by EPR and chlorophyll fluorescence

The UV-A (320-400 nm) component of sunlight is a significant damaging factor of plant photosynthesis, which targets the photosystem II complex. Here we performed a detailed characterization of UV-A-induced damage in photosystem II membrane particles using EPR spectroscopy and chlorophyll fluorescence measurements. UV-A irradiation results in the rapid inhibition of oxygen evolution accompanied by the loss of the multiline EPR signal from the S(2) state of the water-oxidizing complex. Gradual decrease of EPR signals arising from the Q(A)(-)Fe(2+) acceptor complex, Tyr-D degrees, and the ferricyanide-induced oxidation of the non-heme Fe(2+) to Fe(3+) is also observed, but at a significantly slower rate than the inhibition of oxygen evolution and of the multiline signal. The amplitude of Signal II(fast), arising from Tyr-Z degrees in the absence of fast electron donation from the Mn cluster, was gradually increased during the course of UV-A treatment. However, the amount of functional Tyr-Z decreased to a similar extent as Tyr-D as shown by the loss of amplitude of Signal II(fast) that could be measured in the UV-A-treated particles after Tris washing. UV-A irradiation also affects the relaxation of flash-induced variable chlorophyll fluorescence. The amplitudes of the fast (600 micros) and slow (2 s) decaying components, assigned to reoxidation of Q(A)(-) by Q(B) and by recombination of (Q(A)Q(B))(-) with donor side components, respectively, decrease in favor of the 15-20 ms component, which reflects PQ binding to the Q(B) site. In the presence of DCMU, the fluorescence relaxation is dominated by a 1 s component due to recombination of Q(A)(-) with the S(2) state. After UV-A radiation, this is partially replaced by a much faster component (30-70 ms) arising from recombination of Q(A)(-) with a stabilized intermediate PSII donor, most likely Tyr-Z degrees. It is concluded that the primary damage site of UV-A irradiation is the catalytic manganese cluster of the water-oxidizing complex, where electron transfer to Tyr-Z degrees and P(680)(+) becomes inhibited. Modification and/or inactivation of the redox-active tyrosines and the Q(A)Fe(2+) acceptor complex are subsequent events. This damaging mechanism is very similar to that induced by the shorter wavelength UV-B (280-320) radiation, but different from that induced by the longer wavelength photosynthetically active light (400-700 nm).

Clinical presentation and anatomic distribution of chronic venous insufficiency of the lower limb in a typical Mediterranean population

BACKGROUND

The aim of this study was to demonstrate the characteristics of lower limb chronic venous insufficiency (CVI) in a homogeneous Mediterranean population.

METHODS

Investigation of 694 patients with uni- or bilateral symptoms and signs of lower limb CVI using colour duplex scanning. Limbs with previous venous surgery were excluded. The limbs were classified according to history and ultrasonic findings into those with post-thrombotic and those with primary CVI. The clinical presentation according to the CEAP classification was correlated to the anatomic distribution of venous reflux.

RESULTS

Most of the symptomatic limbs (537/656, 81.5%) with primary CVI belonged to classes 1 to 3. In these limbs reflux confined to superficial veins was very common (64.5%, 424/656) whereas the prevalence of deep and perforator vein reflux was 18.5 and 25.5%, respectively. In contrast most of the limbs (69.5%) with post-thrombotic CVI belonged to classes 4 to 6, had a complex pattern of reflux, and involvement of deep and perforator veins was common (86.5 and 48%, respectively). In about a quarter (24%) of patients with suspected primary CVI no reflux was found in either limb on duplex scanning. Most of them (48%) had telangiectasis. Bilateral reflux was found in 71% of the patients with primary CVI.

CONCLUSIONS

The clinical presentation was worse in limbs with post-thrombotic CVI than in those with a primary disease. Post-thrombotic CVI was associated with a complex pattern of reflux, affecting mostly the deep and perforator veins, whereas superficial reflux was the most common pattern in limbs with primary CVI. Therefore, surgery aiming to eliminate superficial reflux would confer only a minimal benefit in limbs with post-thrombotic CVI but would treat the majority of the limbs with the primary CVI. The high prevalence of bilateral reflux found in patients with primary CVI suggests a bilateral predisposition, which supports the hypothesis of the existence of a generalised venous disease.

Experience with new techniques for extraanatomic arterial reconstruction of the lower limb

The aim of this report is to present our experience with new techniques for extraanatomic lower limb arterial reconstruction. Two techniques are described here of construction of an extraanatomical bypass for lower limb revascularization either through the wing of the iliac bone or underneath the iliopsoas fascia through the muscular lacuna close to the anterior superior spine of the iliac crest. Both techniques are recommended for the treatment of a severely injured groin, such as in patients with pelvic malignancy and/or an acute groin bleeding due to postirradiation femoral artery erosion or an infected femoropopliteal bypass graft with severe upper medial thigh sepsis. These techniques were used in nine patients (five with malignancy and four with an infected femoropopliteal bypass graft). Our results showed that the transosseous route through the wing of the iliac bone or underneath the iliopsoas fascia through the muscular lacuna may be considered effective alternate routes for lower limb arterial extraanatomic reconstruction when the common femoral cannot be used for arterial inflow.

Recurrent varicose veins: investigation of the pattern and extent of reflux with color flow duplex scanning

BACKGROUND

This study was conducted to investigate with color flow duplex imaging the patterns and the extent of venous valvular incompetence in recurrent varicose vein disease.

METHODS

One hundred thirty-four limbs of 123 unselected patients who arrived in the outpatient clinic with residual or recurrent varicose veins after undergoing an operation were included. Limbs with history of compression sclerotherapy before or after the operation were excluded. The long (LSV) and short saphenous vein (SSV) systems in all limbs were examined with color flow duplex imaging for detection of the sites and the extent of reflux.

RESULTS

Various patterns of recurrent valvular reflux were seen in both the LSV and SSV systems. Reflux confined to saphenofemoral junction alone or associated with reflux in the LSV system was seen in 29% of the limbs. Reflux in the whole LSV system was very common after saphenofemoral junction ligation was performed (chi-squared test, p<0.01). Most of the limbs (53%) with recurrence in the LSV system had incompetent perforating veins. Incompetent perforators in the thigh were more common after ligation (23%) than stripping (10%), but this finding was not true in the calf. After saphenopopliteal junction ligation was performed, the more common pattern was the reflux in the SSV (75%), whereas after SSV stripping was performed, it was the reflux in the SSV tributaries (64%).

CONCLUSIONS

Multiple patterns of reflux develop in recurrent varicose veins. Precise mapping of the reflux and identification of the possible causes are required to instigate appropriate treatment. Color flow duplex imaging is an efficient noninvasive diagnostic technique to identify venous reflux.