Mono- and double carbonylation of aryl iodides with amine nucleophiles in the presence of recyclable palladium catalysts immobilised on a supported dicationic ionic liquid phase

Silica modified with organic dicationic moieties proved to be an excellent support for palladium catalysts used in the aminocarbonylation of aryl iodides.

Histological examination of vascular lesions caused by stent implantation in humans and in comparative experimental animal model

A comparative analysis of human and experimental animal (canine) tissues was performed to characterize and describe cellular and histological responses during the processes of newly forming intravascular tissues after stent implantation. Routine histological and immunohistochemical evaluation of 20 human samples and 9 samples from animal models were used one day, one week and one month after the stent implantation. After one day of implantation, there was no difference between the human and canine peripheral arteries, suggesting a similar cellular and histological response in the early phase. In contrast, after one week of implantation, during the proliferative phase the repairing human tissue showed less intensive production of inflammatory cells and more intensive increase in number of vascular cells than did the canine model. In addition, cellular changes normally restituted by the end of one month in canine peripheral arteries, but vascular cells persisted in human atherosclerotic arteries. In conclusion, results of this study suggest differences in both phases of vascular repair in the post-stented period, because both proliferative and regressive phases showed histological differences in canine and human samples. In canine, the restitution of vascular wall was completed by the end of first month but persistent vascular cell proliferation was visible in the human peripheral arteries. It can be suggested that delayed cellular response might indicate restenosis but also can be considered considered as a progression of the original arterial disease.

Effect of vitamin E on reperfusion injuries during reconstructive vascular operations on lower limbs

INTRODUCTION

The challenge against reperfusion injury and tissue oxidative stress, especially in vascular surgical interventions has an essential importance to reach the optimal clinical result. Numerous experimental attempts have proved the positive antioxidant effect of vitamin E in both chronic and acute phase models. In our study we monitored the effect of continuous preoperative treatment with vitamin E, on oxidative stress and tissue inflammation reactions developed after reconstructive operations.

PATIENTS AND METHODS

32 patients have been involved in a randomized, prospective study, all suffering from AFS occlusion proved by angiography, and all undergone supragenual reconstruction. Duration of ischemia and amount of tissues under vascular clamping were almost the same in all patients. In the group treated with E-vitamin, we administered 1 x 200 mg of vitamin E p/o from the preoperative day till the 7th post operative day. Patients of the second group did not receive vitamin E.

MATERIALS AND METHODS

Peripheral blood samples were collected immediately before operation and at the end of the second reperfusion hour (early reperfusion period). Late reperfusion period has been monitored by analyzing blood samples taken at 24th hour and 7th day next to the operative ischemia. Among oxidative stress parameters, direct measurement of reactive oxygen intermediator (ROI) and determination of antioxidant state (GSH, Total-SH group, SOD) have been performed. Malondialdehyde was chosen as marker for lipidperoxidation. Inflammation reactions were monitored up on expression of adhesion molecules (CD11a and CD18). We also controlled the oscillation of myeloperoxidase (MPO) activity.

RESULTS

Our study has proved that preoperative (from the preoperative day till the 7th post operative day) administration of 200 mg vitamin E could reduce the level of oxidative stress developed after ischemic-reperfusion insult (lipidproxidation, antioxidant enzymes). According to our results, the prooxidant-antioxidant imbalance also diminished in the group with E-vitamin treatment. We proved that elective administration of vitamin E could decrease the WBC activity (MPO activity, free radicals production, expression of adhesion molecules) and its consequential local inflammation process, during early reperfusion.

Pathology and diagnostic options of lower limb compartment syndrome

BACKGROUND

The indication of surgical treatment in lower limb compartment syndrome mostly depends on the clinical signs which can be often uncertain, resulting in delayed insufficient intervention.

AIM

The aim of the study was to evaluate the progression of compartment syndrome by measuring of intracompartmental pressure and monitoring of decreased tissular oxygenation, indicating an insufficient secondary microcirculation.

MATERIALS AND METHODS

16 patients were examined in our study (12 males, 4 females, mean age: 62.7+/-9.5 years), who underwent acute lower limb revascularization surgery for a critical (lasting more than 4 hours) limb ischemia. The indications were: 5 iliac artery embolizations and 11 femoral artery occlusions. After revascularization, on the second postoperative day, we detected significant lower limb edema and swelling of several grade. To monitor the elevated intracompartmental pressure (ICP) and to evaluate the extremital circulation, we used KODIAG pressure meter and the tissular oxygen saturation (StO2) was measured by near-infrared-spectroscopy.

RESULTS

In 12 cases the ICP exceeded the critical 40 mmHg. In these patients the average StO2 was 50-53%, in spite of complete recanalization. In these cases we made urgent, semi-open fasciotomy. In 4 cases, where the clinical aspect showed compartment syndrome, the measured parameters did not indicate a surgical intervention (ICP: 25-35 mmHg, StO2: around normal).

SUMMARY

A novel approach in our examination is that, besides empirical therapeutic guidelines generally applied in clinical practice, we established an objective, parameter-based ("evidence based medicine") surgical indication strategy for the lower limb compartment syndrome. Our parameter results produced by the above pressure and saturation measurements help the clinicians to decide between conservative and operative treatment of the disease.

Morphological analysis of the connective tissue reaction in linear hypertrophic scars treated with intralesional steroid or silicone-gel sheeting. A light and electron microscopic study

The linear hypertrophic scar has become the most common type of pathologic scarring. Silicone-gel sheeting is the first line therapy while intralesional steroid is the second. A light and electron microscopic analysis was carried out to reveal differences in tissue reaction following the two different treatments. Two groups of 12 patients each were treated for 4 months. For the first group, diluted Triamcinolone acetonide was injected until an inactive state was achieved. The other group of patients was treated with silicone-gel sheeting. The scars were examined every two weeks and their appearance documented. After reaching the expected therapeutic response, inactive scars were removed. The excised scars were evaluated through light microscopic histopathology and electron microscopy. The light and electron microscopic observations revealed marked differences following treatments. The activity of fibroblasts and the numbers of collagen fibers forming bundles decreased and the orientation of the collagen fibers was more variable in the treated scars. The amount of elastic fibers increased after both steroid and silicone-gel sheeting treatment. Vascularization was also slightly changed, with more capillaries and fewer pre-capillary arteries detected in the treated scars. Both treatments resulted in the same decrease in score but steroid treatment was more rapid in onset. We suggest that the two different treatments work through different mechanisms, although the final functional outcome is similar.

Reperfusion injury and inflammatory responses following acute lower limb revascularization surgery

After revascularization of an acute arterial occlusion the development of a serious ischaemic-reperfusion injury is a menacing challenge and a hard task in peripheral vascular surgery. A whale of evidences point to oxidative stress, as an important trigger, in the complex chain of events leading to reperfusion injury. In the present study authors aimed to examine oxidative stress parameters, antioxidant-prooxidant state and leukocyte adhesion molecules (CD11a and CD18) expression following acute revascularization surgery of lower limb.10 patients were examined in the prospective randomized study. Peripheral blood sample was collected in ischaemic period, and after reperfusion in the 2nd and 24th hours, and on 7th day. Superoxide-dismutase activity, reduced glutathion concentration and leukocytes free radical production were measured. The degree of lipidperoxidation was marked with the quantity of malondialdehyde. The expressions of adhesion molecules were measured with flowcytometry.The speed and rate of free radical production significantly increased in the early reperfusion (p<0.05). The level of antioxidant enzymes decreased after revascularization. The CD11a and CD18 expression of the granulocytes significantly (p<0.05) decreased right after the revascularization, but with a gradual elevation until the 7th day they exceed the ischaemic value. Our results showed a time specific turnover of the sensitive antioxidant-prooxidant balance after revascularization operation.

Ischaemic postconditioning reduces peroxide formation, cytokine expression and leukocyte activation in reperfusion injury after abdominal aortic surgery in rat model

OBJECTIVE

We studied the protective effects of ischaemic postconditioning (PS) on ischemia-reperfusion injury of the lower extremities in a rat model of abdominal aortic intervention. We aimed to examine the evoked oxidative stress, cytokine expression and leukocyte activation after revascularisation surgery.

METHODS

Anesthetized animals (48 Whistar rats) underwent a 60 min infrarenal aorta cross-clamping. After the ischaemic period, an intermittent 4 times 15 s reperfusion--15 seconds ischaemic episodes--were applied (ischaemic postconditioning: group PS). Then we started a 120 min reperfusion in the aorta. In untreated group animals underwent a long ischaemia (60 min) and the following reperfusion (group IR). Peripherial blood samples were collected before operation, and in early (5, 10, 15, 30, 60 and 120 min) reperfusion periods. Serum peroxide level, TNF-alpha concentration, myeloperoxidase (MPO) activity and PMA-induced leukocyte ROS production were measured.

RESULTS

In PS group, plasma peroxide level elevation was significantly lower in very early reperfusion (5-30 min) comparing to non-conditioned IR group (10.04+/-1.9 microM/l vs. 16.91+/-3.67 microM/l, p<0.05). PS also reduced serum TNF-alpha concentration (167.41+/-31.26 microg/ml vs. 116.55+/-12.04 microg/ml, p<0.05), MPO activity (1.759+/-0.239 microM/ml vs. 1.22+/-0.126 microM/ml, p<0.05) and leukocyte activation detected by PMA-induced leukocyte ROS production (5.7+/-0.96 AU/10(3) cells vs. 4.63+/-0.69 AU/10(3) cells).

CONCLUSIONS

Ischaemic postconditioning could reduce ROI production after IR in early reperfusion period, thus limiting ROI mediated tissue lesion, cytokine-leukocyte activation and inflammatory responses. PS seems to be an effective tool in vascular surgery to reduce reperfusion injuries after revascularization interventions.

Three generations of alpha,gamma-diaminobutyric acid modified poly(propyleneimine) dendrimers and their cisplatin-type platinum complexes

Three generations of alpha,gamma-diaminobutyric acid modified poly(propyleneimine) dendrimers [DAB(AM)n, n = 4, 8, 16] containing 4, 8, 16 free amino groups were coupled with Boc-protected alpha,gamma-diaminobutyric acid (DABA) moieties in high yields. These modified dendrimers were deprotected and the chiral dendritic amines with 8, 16 and 32 amino groups on the surface were isolated in excellent yields. Dendrimers with cisplatin moieties at the periphery were obtained in the reaction of the free amine dendrimers and potassium tetrachloroplatinate(II). The highly insoluble complexes were isolated as hydrates and characterized by means of IR, TGA and elemental analysis.

Mass spectrometric studies on the coupling model reaction towards alkenyl-aryl ketones

The palladium catalysed coupling reactions of 1-iodo-cyclohexene have been investigated with the aim of the synthesis of model compounds towards unsaturated aryl-alkenyl ketones of practical interest in carbonylative Suzuki reaction. In addition to the target compounds, the formation of 1-aryl-cyclohexene derivatives, 1,1'-bi(cyclohex-1-en-1-yl), 1,2-dicyclohex-1-en-1-yl-ethane-1,2-dione, dicyclohex-1-en-1-yl-ketone and 1-aryl-2-cyclohexenyl-cyclohexene derivatives, as well as their isomerization products, have been observed in parallel and consecutive reactions, respectively. The complex reaction mixtures have been analysed with GC-MS providing valuable information to the investigation of the homogeneous catalytic reaction.

Heck reactions of steroidal alkenyl iodides

Heck reactions of some steroid derivatives possessing iodo-alkenyl moiety (17-iodo-androst-16-ene, 1, 17-iodo-4-aza-4-methyl-androst-16-en-3-one, 2, 17-iodo-4-aza-androst-16-en-3-one, 3) were carried out in the presence of palladium catalysts using various olefins (methyl acrylate, ethyl methacrylate, allyl alcohol and allyl acetate) as coupling partners. With methyl acrylate, a side reaction was observed: the coupling product underwent a Diels-Alder reaction with the excess of methyl acrylate resulting in a six-membered carbocyclic E-ring. Reaction conditions of the synthesis of the Heck-product were optimized. Although the coupling with allyl alcohol led to the formation of 21-formyl-16-pregnene derivatives, the synthesis of the corresponding steroidal unsaturated alcohol could be achieved only via hydrolysis of the coupling product of the alkenyl iodide with allyl acetate.

Internal carotid stent implantation with angioscopic control

Stent implantation is a method, which is being used more and more often, mainly in the field of peripheral arteries, but coronary stent implantation is also well-known. The authors apply this procedure for patients, who besides the carotid bifurcation stenosis also suffer from the internal carotid stenosis in a longer section of the artery. The indication are as follows: 1 in the case of internal carotid stenosis in a longer section we assure the flow with the help of carotid thrombendarterectomy and slove the run-off with balloon catheter dilatation and stent implantation. 2. in the case of a stenosis in a short section we use stent implantation to avoid dissection of the intima. With each intervention we perform the carotid bifurcation thrombendarterectomy. The authors made the first intervention 15 months ago, since then we have performed 17 stent implantations. One of the 17 patients developed a temporary stroke (TIA). This is a new method, further cases are needed for long-term experiences. Intervention under eye-control can be carried out with more confidence. As regards to the post-operative medicinal treatment, the administration of thrombocyte aggregation-blockers or heparinoid preparation (e.g.: PPS-SP 54) after the stent implantation has become a routine therapy. Summarized the foregoing, these cases constitute about 10-15% of all carotid operations, therefore the authors would like to make it clear, that this is not a routine method, but a possibility, strictly respecting the above-mentioned indications.

The basic and the practical way of treating of diabetic foot

Developed atrophic ulcer and infected alterations of the foot, as a result of complications of DM, according to the available literature, 40-80% of the performed amputations are not necessary even though in practice they do occur. In our practice even the severely altered and infected extremities which look serious are considered as primarily a savable extremity if the conditions are present. The state of circulation of the extremity and the condition of the limb are evaluated carefully, and the sugar level is monitored continuously. According to our experience, every progressing process, the alteration of the host sugar level can be held as responsible. That is why after the early therapeutic period, careful monitoring of the insulin level is a priority. At our out-patient department we are daily confronted during routine wound inspections by cases of necrotizing osteomyelitis which to our experience are doomed for removal. In 1995 at the out-patient section of the vascular surgery ward we saw over 9000 patients, more than 500 of which included patients with diabetic angio/neuropathy complications. The nursing of this group of patients during that year only to 33 large vessel reconstructive operations and 26 cases of amputations. We conclude from the above statistics that not all cases of osteomyelitis cases should lead to limb amputation. Due to the nature of the condition, careful monitoring with early preventive measures, plus family support play a crucial role in the outcome of the condition. This complex process is better handled if special diabetic centres were set-up to monitor patients progress.

Steroidal alkenylphosphonates via palladium-catalyzed coupling reactions

The palladium-catalyzed coupling of various 17-iodo-delta 16 steroids (17-iodo-androst-16-ene, 17-iodo-4-methyl-4-aza-androst-16-en-3-one, and 17-iodo-4-aza-androst-16-en-3-one) with dialkyl phosphites (dimethyl phosphite, diethyl phosphite, and diisopropyl phosphite) was examined in detail. The only successful condition for homogeneous coupling involved carrying out the reaction in the absence of any solvents. A large excess of dialkyl phosphite was used, which means that the phosphite itself acted as a solvent. Eight new androst-16-ene derivatives with phosphonate groups at C-17 were synthesized and characterized. These steroids are of pharmacological interest as potential 5 alpha-reductase inhibitors. Under the same conditions, methylation of lactam NH was observed using dimethyl phosphite.

Homogeneous catalytic dehalodimerization of 17-iodo-delta 16 steroids

17-Iodo-delta 16 steroids undergo selective dimerization and carbonylative dimerization in the presence of palladium catalysts in dimethylformamide which result in 16-17'-coupled dienes and 17-carboxylic anhydrides, respectively. Moderate to good yields have been obtained for both types of dimers.

Palladium-catalyzed homogeneous coupling reactions of steroids with organostannanes

Direct and carbonylative coupling reactions of various steroid derivatives possessing iodo- and bromo-alkenyl moiety (17-iodo-androst-16-ene, 1, 17-bromoandrost-2,16-diene, 2, 17-iodo-4-aza-4-methylandrost-16-en-3-one, 3, 17-iodo-4-azaandrost-16-en-3-one, 4) with vinyltributylstannane and ethynyltributylstannane were carried out in the presence of various palladium catalysts. While carbonylation took place only with vinyltributylstannane, 17-vinyl-, and 17-ethynyl-delta 16 steroids were produced via direct coupling with vinyltributylstannane and ethynyltributylstannane, respectively. Activities of some catalysts based on Pd(0) and Pd(II) precursors were compared, and Pd(PPh3)4 was found to be superior to other complexes in most cases. In the coupling of 17-iodoandrost-16-ene with organostannanes Pd2(dba)3 + 8 AsPh3 in situ catalyst was found to be even more effective.

[Late results of the Palma operation]

Since 1981, 54 femoro-femoral crossover saphenous bypass (Palma-operation) were performed for chronic venous insufficiency caused by unilateral iliac vein occlusion. Long-term patiency rate and clinical results were evaluated by radioisotope venography and venous occlusion plethysmography. Plethysmography demonstrated significant improvement of maximal venous outflow after operation. Radioisotope venography showed remarkable long-term patency rate of Palma-bypass (of 42 operation, 29 patent graft). Long-term clinical results appeared to be excellent after operation of isolated iliac vein occlusion, whereas the results after operations performed with postthrombotic changes in more distal deep veins were not acceptable, therefore a more critical preoperative selection seems to be necessary.

Direct and carbonylative vinylation of steroidal triflates in the presence of homogeneous palladium catalysts

The palladium-catalyzed vinylation of several steriod 2-enyl- and 3,5-dienyl-3 triflates and estrone-3-triflate was systematically examined using vinyltributylstannane as a vinylating agent. In carbon monoxide atmosphere the insertion of a CO molecule took place and unsaturated ketones were obtained. In this way new steroid derivatives containing unsaturated side chain were produced, which can serve as starting material for further functionalization of the steroid skeleton.

Does pentoxifylline prolong the walking distance in exercised claudicants? A placebo-controlled double-blind trial

The aim of this study was to test whether in claudicants oral pentoxifylline, given for twelve weeks in addition to physical exercise, prolongs the walking distance more than placebo plus exercise. Forty outpatients were randomized into group A (2 x 600 mg oral pentoxifylline per day) or group B (placebo). Both groups received the same exercise program in addition. The maximal and painfree walking distances and blood viscosity were measured. Intergroup differences in terms of blood viscosity reached the level of significance only after twelve weeks (p = 0.006 at shear rate of 94.5 s-1), but values of group A continuously decreased and those of group B continuously increased. After one and eight weeks, but not after twelve weeks, the maximal walking distances were significantly longer in group A than in group B. At no point were there significant intergroup differences in terms of painfree walking distance. The data suggest that pentoxifylline is clinically effective in claudicants even when given in addition to exercise. The benefit of drug plus physical therapy compared with exercise alone could be observed mainly in the first weeks of treatment and may wear off during long-term therapy.

[Data on possibilities of rehabilitation of lower limb amputees]

The authors investigated ways to improve the results of rehabilitation during the course of their clinical practice. During the last 2 years, amputation was performed on 136 patients and 50 patients were supplied with temporary protheses. 38 patients out of 50 answered the question form supplied. After analysis of the question form, the authors summarized the possibilities to improve the results of prolonged mobilisation and rehabilitation. This programme stresses the need for 1. early mobilisation-teaching to walk and 2. care of body and soul.

[The role of autotransfusion in vascular surgery]

Use of autotransfusion has recently come into the limelight of clinical practice especially because of the AIDS-risk and financial considerations. Authors have analysed data of 20 patients with peripheral arterial disease at whom hemodilution were carried out before the operation with the aim of using autotransfusion. Attention is called to the importance of autotransfusion and its applicability in the practice of other sorts of surgery.