Field performance of chitinase transgenic silver birches (Betula pendula): resistance to fungal diseases.

A field trial of 15 transgenic birch lines expressing a sugar beet chitinase IV gene and the corresponding controls was established in southern Finland to study the effects of the level of sugar beet chitinase IV expression on birch resistance to fungal diseases. The symptoms caused by natural infections of two fungal pathogens, Pyrenopeziza betulicola (leaf spot disease) and Melampsoridium betulinum (birch rust), were analysed in the field during a period of 3 years. The lines that had shown a high level of sugar beet chitinase IV mRNA accumulation in the greenhouse also showed high sugar beet chitinase IV expression after 3 years in the field. The level of sugar beet chitinase IV expression did not significantly improve the resistance of transgenic birches to leaf spot disease. Instead, some transgenic lines were significantly more susceptible to leaf spot than the controls. The level of sugar beet chitinase IV expression did have an improving effect on most parameters of birch rust; the groups of lines showing high or intermediate transgene expression were more resistant to birch rust than those showing low expression. This result indicates that the tested transformation may provide a tool for increasing the resistance of silver birch to birch rust.

Antifungal activity of stilbenes in in vitro bioassays and in transgenic Populus expressing a gene encoding pinosylvin synthase.

The effect of two stilbene compounds, pinosylvin and resveratrol, on the growth of several fungi was evaluated in plate tests. Wood decay tests were carried out with birch and aspen samples impregnated with the two stilbenes. In plate experiments, resveratrol had an enhancing effect on growth at concentrations where pinosylvin was already enough to prevent the growth of most fungi studied. Pinosylvin impregnated at 0.2% (w/w) concentration significantly reduced the decay caused by all fungi except Phellinus tremulae. In contrast, a resveratrol content of 0.8%, did not protect the wood from decay. A pinosylvin-synthase-encoding gene from Pinus sylvestris was transferred into aspen ( Populus tremula) and two hybrid aspen clones ( Populus tremulax tremuloides) by Agrobacterium tumefaciens-mediated transformation. Transgenic plants accumulated pinosylvin synthase-specific mRNA and showed stilbene synthase enzyme activity in vitro. Transgenic aspen line H4 showed increased resistance to Phellinus tremulae, while two hybrid aspen transformants decayed faster than the control trees. However, we were unable to detect the accumulation of stilbenes in the transgenic plantlets.

MR angiography with three-dimensional time-of-flight and targeted maximum-intensity-projection reconstructions in the follow-up of intracranial aneurysms embolized with Guglielmi detachable coils.

BACKGROUND AND PURPOSE: Intra-arterial contrast angiographies are generally used to confirm treatment results of endovascular neurointerventions such as aneurysm obliteration. We compared MR angiography with digital subtraction angiography (DSA) as a follow-up technique for the detection of aneurysmal remnant cavities and arterial patency in patients treated for intracranial aneurysms with Guglielmi detachable coils (GDCs). METHODS: In 20 consecutive patients, follow-up MR angiography and routine intra-arterial cerebral angiography were performed on the same day 1 to 7 months (mean, 4.5 months) after embolization with GDCs. MR angiographic data were postprocessed for subvolume maximum intensity projections centered on the region of the treated aneurysm. Hard copies of both imaging studies were interpreted independently in a blinded fashion to record and compare remnant cavities, location of residual flow, and adjacent arterial narrowing, using DSA as the standard of reference. The interpreters also established an occlusion grade for the treated aneurysms as evidenced on DSA images and evaluated MR angiograms for artifactual effects. RESULTS: Overall sensitivity and positive predictive value of MR angiography in revealing aneurysmal remnant cavities were both 90%. Specificity in ruling out a remnant cavity with MR angiography was 91%. One remnant cavity was missed by MR angiography, and in five patients, false adjacent arterial encroachments were reported. CONCLUSION: MR angiography may be useful in the long-term follow-up of successfully treated small and medium-sized aneurysms after concurrent primary verification of their occlusion with DSA.

Patient outcome after endovascular treatment of intracranial aneurysms with reference to microsurgical clipping.

OBJECTIVES: Endovascular treatment of intracranial aneurysms with Guglielmi detachable coils (GDC) has found growing acceptance worldwide, and partially replaced conventional microsurgery. In this study clinical and angiographical results of embolization are reviewed. In addition, long-term neuropsychological patient outcome with reference to surgery is assessed. Indications for screening and follow-up of the patients as limitations and recent achievements of aneurysm embolization are discussed. MATERIAL AND METHODS: Angiographical and clinical follow-up of the first 44 patients with 48 GDC-coiled aneurysms are reviewed. Postprocedural clinical, emotional and social (CES) outcome on disability scale as scored from postal questionnaire data is presented and compared to 106 currently operated patients. RESULTS: In 75% of the embolized aneurysms successful occlusion was achieved, procedural mortality was 2.3% and morbidity 18.2%. Clinical status of all 15 patients with unruptured aneurysms preserved. Of the surviving 29 patients with ruptured aneurysms 12 improved and the rest preserved their clinical status. In 91% of the embolized patients and in 85% of the operated patients CES outcome was categorized as good or excellent. The difference was statistically nonsignificant. CONCLUSION: Embolization with GDC is a feasible, effective and safe mini-invasive method in small aneurysms with a small neck. However, intentional parent artery occlusion, novel endovascular techniques and embolic agents or supplementary surgery may be necessary in selected cases. Neuropsychological long-term outcome of the patients treated for an intracranial aneurysm does not differ much between GDC embolization and microsurgical clipping.

Microcatheter embolization of hemorrhages.

PURPOSE: To evaluate the efficacy of embolotherapy using microcatheters in patients with hemorrhage from various locations. METHODS: Among 29 patients there were 13 with severe epistaxis, 7 with gastrointestinal bleeding, 4 with hemorrhage in the kidney, 4 with bleeding in pelvic organs and 1 with bleeding in the shoulder region. In all cases, a Tracker-18 or Tracker-10 microcatheter was advanced coaxially through a 4.1 Fr guiding catheter in order to reach the bleeding site as distally as possible. Polyvinyl alcohol microparticles and/or platinum microcoils were used as embolic material. RESULTS: The bleeding was stopped in 90% (26 of 29) of cases. In 66% of cases the treatment was curative, in 7% preoperative, and in 17% palliative. There were 3 clinical failures. CONCLUSION: Microcatheter embolization is an effective and safe means of managing different kinds of hemorrhage of various causes from a variety of sites.

Intracystic hemorrhage in pancreatic pseudocysts: initial experiences of a treatment protocol.

The treatment recommendations for intracystic hemorrhage in pancreatic pseudocysts are various. We have used a defined treatment protocol in these difficult cases. The experiences gained are reported here. Patients with clinical signs of ongoing bleeding and with hemorrhagic pancreatic pseudocyst in ultrasonography and computed tomography (CT) were studied with urgent angiography. Patients showing a pseudoaneurysm were treated with immediate embolization and delayed elective surgery whenever candidates for surgery. During a 5-year period 10 patients were treated according to the protocol. Pseudoaneurysm was demonstrated and subsequent embolization performed in six. Angiography was negative in four patients. During the study period two additional patients were treated conservatively without angiography because the bleeding had stopped 2 weeks prior to the referral to our institution. Two patients were electively operated on and the remaining 10 patients were treated conservatively. Fever and elevated transaminases developed in one of the six patients after the embolotherapy. One of the four embolized patients who were not operated on developed pseudocyst infection 4 months after the embolization. One of the 10 conservatively treated patients died (1/10 = 10%; total mortality, 1/12 = 8%) during the follow-up for infection complications of necrotizing pancreatitis 2 months after the initial bleeding. Another conservatively treated patient with negative angiography had recurrent bleeding during the follow-up but could not be operated on due to severe liver cirrhosis. In the remaining eight patients pseudocysts resolved during the 3-month to 3.5-year follow-up as confirmed by CT. The low rates of mortality and rebleeding support a fairly conservative approach for hemorrhagic pancreatic pseudocysts.

Diagnosis and embolizing of spinal arteriovenous malformations.

Spinal arteriovenous malformations are uncommon disorders associated with considerable difficulty in diagnosis and treatment. They are divided into dural arteriovenous fistulas and intradural medullary spinal cord angiomas. In this retrospective series of six patients the clinical outcome of embolization is presented. The patient material consisted of three dural fistulas and three cord angiomas, one of which bled causing sudden paresis, pain and incontinence. In the remaining five patients the symptoms were progressive consisting of paraesthaesias, paraparesis, pain and incontinence. The clinical status of four patients was not changed after the treatment, one deterioriated and one improved. There were no bleedings after the therapy. In one patient spinal angiography for follow-up was performed and recanalization was seen in the dural fistula after particle embolization. Also, in one cord angioma embolized with particles reflow appeared in the immediately repeated angiography. For permanent angioma occlusion tissue adhesive is preferred as embolic material. Surgical therapy as an alternative or adjuvant to embolization is discussed with a review of the literature. Early timing of the therapeutic intervention is stressed to avoid the development of irreversible ischaemic medullopathy and to prevent haemorrhage. The therapeutic procedures at the early stage of the disease may be curable or, at least, halt the progression of the symptoms. Cross-sectional imaging studies and myelographies may reveal the lesion. For the definitive diagnosis of spinal angioma with its vascular feeders and for the evaluation of its occlusion grade after the therapy selective spinal angiography is needed.

Microcatheter embolization of arteriovenous fistulas in the subclavian region. Report on three cases.

PURPOSE: The retrospective evaluation is presented of 3 patients treated with endovascular embolization of arteriovenous fistulas (AVFs) in the subclavian region. MATERIAL AND METHODS: Three patients, 2 women and one man, were treated endovascularly in local anesthesia using microcatheters and fibered platinum microcoils. Two patients were asymptomatic and one had unexplained chest pain. RESULTS: All 3 AVFs were successfully occluded. One coil slipped through the fistula into the pulmonary circulation but caused no clinical sequelae. CONCLUSION: AVFs in the subclavian region can be treated by using microcatheters and fibered platinum microcoils.