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Biomedical subjects

P Konrad

Publications and source records attributed to P Konrad.

At least 19 recordsLinked to original sources
PubMed2006

Remodeling of the thoracic aorta after stent grafting of type B dissection: a Swedish multicenter study.

AIM: Endovascular repair of complicated type B dissections has evolved as a promising alternative to open repair. Previous studies have indicated that continued false lumen flow is a predictor of continued aortic dilatation and risk of rupture during follow-up. This multicenter study was conducted to analyze the postoperative changes of the false lumen after endografting of complicated type B dissections. METHODS: All patients treated with endovascular stent grafts for thoracic type B dissections at 5 major Vascular Centers in Sweden were identified through local databases. Review of charts and all available pre- and postoperative CT scans were performed to identify demographics, indications for repair as well as postoperative changes of the aorta and false lumen. RESULTS: A total of 129 patients treated for type B dissections between 1994 and December 2005 were identified. Median radiological follow-up was 14 months. Fourteen patients died perioperatively leaving 115 patients available for analysis. Seventy-four of these had CT imaging of sufficient quality for morphological analysis. The vast majority of acute patients were treated for rupture or end-organ ischemia whereas most chronic patients were treated for asymptomatic aneurysms. In 80% of patients, the false lumen thrombosed along the stent graft but it remained perfused distal to the stent graft fixation in 50% of patients. Only 5% of patients presented with aortic enlargement of the stent grafted area when adequate proximal sealing was achieved. The distal, uncovered aorta displayed expansion in 16% of patients. CONCLUSIONS: The stent grafted thoracic aorta after type B dissection appears to be stabilized by covering the primary entry site with a stent graft in the majority of both acute and chronic dissections. The uncovered portion of the aorta distal to the stent graft, however, remains at risk of continuous dilatation. Stent grafting for complicated type B thoracic dissections seems to be a treatment option with reasonable morbidity and mortality even though the incidence of severe complications is still significant.

Adult↗
PubMed2005

Effects of three months of low molecular weight heparin (dalteparin) treatment after bypass surgery for lower limb ischemia--a randomised placebo-controlled double blind multicentre trial.

OBJECTIVES: To test the hypothesis that long-term postoperative dalteparin (Fragmin), Pharmacia Corp) treatment improves primary patency of peripheral arterial bypass grafts (PABG) in lower limb ischemia patients on acetylsalicylic acid (ASA) treatment. DESIGN: Prospective randomised double blind multicenter study. MATERIALS AND METHODS: Using a computer algorithm 284 patients with lower limb ischemia, most with pre-operative ischemic ulceration or partial gangrene, from 12 hospitals were randomised, after PABG, to 5000 IU dalteparin or placebo injections once daily for 3 months. All patients received 75 mg of ASA daily for 12 months. Graft patency was assessed at 1, 3 and 12 months. RESULTS: At 1 year, 42 patients had died or were lost to follow-up. Compliance with the injection schedule was 80%. Primary patency rate, in the dalteparin versus the control group, respectively, was 83 versus 80% (n.s.) at 3 months and 59% for both groups at 12 months. Major complication rates and cardiovascular morbidity were not different between the two groups. CONCLUSIONS: In patients on ASA treatment, long-term postoperative dalteparin treatment did not improve patency after peripheral artery bypass grafting. Therefore, low molecular weight heparin treatment cannot be recommended for routine use after bypass surgery for critical lower limb ischemia.

Aged↗
PubMed2000

Internal carotid artery dissection.

The purpose of this review is to increase the awareness of internal carotid artery dissection (ICAD), a potentially serious and probably underdiagnosed condition. ICAD is a not uncommon cause of stroke in young patients. ICAD may occur spontaneously or as a result of trauma. However, the "spontaneous" dissection is often preceded by a trivial trauma. The typical patient presents with ipsilateral headache or neck pain, ipsilateral Horner's syndrome and delayed ischemic symptoms from the ipsilateral hemisphere or retina. Conventional angiography, the gold standard for diagnosis, tends to be replaced by non-invasive diagnostic methods. There are no evidence-based guidelines for therapy although anticoagulation is most commonly used. The references are selected from the Medline database for the years 1966-1997.

Anticoagulants↗
PubMed2000

Carotid atherosclerosis in relation to symptoms from the territory supplied by the carotid artery.

OBJECTIVES: To investigate the relationship between intima-media thickness in the common carotid artery, plaque morphology in the carotid bifurcation and symptoms of cerebral embolism. Design prospective study of consecutive patients referred for carotid duplex examination. METHODS: One hundred and eighty-eight patients were classified by one of two neurologists into four categories (symptomatic, asymptomatic, undefined, uncertain). Carotid atherosclerosis was measured by means of high-resolution ultrasound technique. Carotid plaques were classified based on visual evaluation of plaque echogenicity. RESULTS: Intima-media thickness (IMT) was correlated to presence of plaques, age and gender, but not to symptoms referable to the carotid circulation. Carotid plaques were more common in symptomatic than in asymptomatic vessels (p<0.05). There was no difference in plaque occurrence between the ipsi- and contralateral sides in the symptomatic patients, neither in frequency of echolucent plaques between the sides or between symptomatic and asymptomatic patients. Echogenic plaques were more common and generally smaller than echolucent plaques. CONCLUSIONS: IMT correlates with presence of plaques, but not with symptoms from the territory supplied by the carotid artery. Echolucent plaques in the carotid bifurcation are not more frequently symptomatic than echogenic plaques are, in patients with low-to-moderate degree of carotid stenosis.

Adult↗
PubMed1997

[The nerve supply of the knee joint].

The paper presents the present state of research on the most important receptors of joints and muscles with regard to occurrence, structure, and function. Proprioception relies on the nervous supply of the tissues in the knee joint, and on the surrounding muscles and tendons; it is the basis of coordination.

Afferent Pathways↗
PubMed1997

[Therapeutic physical training after knee injuries].

Exercise training is a therapy that accompanies and follows physiotherapy. Basic training principles are discussed on the basis of motricity research. Initially, exercise therapy mostly trains patients to recall and standardize the execution of exercise programs. With the patient's increasing power of endurance, the intensity of extent of training are increased. Exercise therapy eventually aims at particularly preparing the patient for the activities of daily living and the sportsman for the requirements specific to training and competition.

Combined Modality Therapy↗
PubMed1996

An analysis of the posterior epidural ligament role on the cervical spinal cord.

STUDY DESIGN: Laminectomy was performed on cats to destroy the posterior epidural ligament. Evoked potentials and spinal cord blood flows quantified the spinal cord function before and after cervical flexion. OBJECTIVES: This work describes a relationship between the loss of the posterior epidural ligaments and cervical spinal cord injury. SUMMARY OF BACKGROUND DATA: The posterior epidural ligaments of the human cervical spine have been recently described. These ligaments theoretically prevent injury to the spinal cord by resisting collapse of the dura during cervical flexion. METHODS: The animals were divided into three experimental groups: 1) control: no laminectomy and standard position, 2) flexion control: no laminectomy and known imposed flexion, 3) laminectomy (C3-C7) and flexion. Motor-evoked potentials and evoked spinal cord potentials were recorded to quantify the spinal cord functions. Radioactive microspheres were used to quantify ischemia in the spinal cord. RESULTS: Control subjects showed blood flows of 36 mL/100 g/min (C3-C4) to 46 mL/100 g/min (C7-C8). Flexion control subjects did not experience significant reductions in blood flows or substantial change in evoked potentials. The laminectomy plus flexion group experienced reduced blood flows and substantial motor-evoked potentials and slight evoked spinal cord potential changes with 50 degrees, 60 degrees, and 70 degrees flexion. Blood flow reduction was greater in the anterior half of the C7-C8 segments compared with the posterior half at 60 degrees flexion. Evoked spinal cord potentials were less vulnerable than motor-evoked potentials. CONCLUSIONS: The role of the posterior cervical epidural ligaments is to anchor the posterior dura mater to the ligamentum flavum. Loss of the ligaments allows anterior displacement of the posterior dura mater in flexion. Abnormal distribution of or lack of the cervical posterior epidural ligaments may lead to flexion myelopathy.

Animals↗
PubMed1994

Prospective study of 713 below-knee amputations for ischaemia and the effect of a prostacyclin analogue on healing. Hawaii Study Group.

In 51 hospitals in six European countries 713 patients requiring below-knee amputation for ischaemic disease were studied prospectively. The patients were allocated randomly to receive standard postoperative treatment or standard treatment plus intravenous infusion of the prostacyclin analogue iloprost for 6 h per day over 14-21 days. Healing of the amputation stump and the need for reamputation at a higher level were similar in the two groups. Overall at 3 months 59 per cent of stumps had healed, 19 per cent of patients had required reamputation at a higher level, 11 per cent had died and the remaining 11 per cent remained with unhealed stumps. Preoperative characteristics were analysed as possible risk factors or markers for primary healing, reamputation and death. Previous arterial reopening procedures (surgical or radiological) almost doubled the chances of primary stump healing (P < 0.05). The surgeon's assessment of the likelihood of healing was wrong in 21 per cent of cases in which the operating surgeon thought that healing would probably occur and in 52 per cent of those in which it was thought healing was improbable.

Adult↗
PubMed1992

Acute thrombogenicity of collagen coating of dacron grafts: an experimental study in sheep.

The early stages of platelet accumulation in two types of sealed interposition Dacron grafts implanted in the carotid arteries of sheep have been studied. One type was externally coated with collagen (Haemaguard) while the other experimental conduit had an additional inner lining of the same substance. 32P-labelled platelets were used to assess platelet accumulation and corrections for wall absorption were calculated. The activities in both types of grafts were highest proximally and decreased towards the distal anastomosis. The increases in the doubly-sealed grafts were larger than in those that had been single sealed, presumably reflecting activation of platelets in contact with collagen at the graft-wall and bloodstream interface. In addition, a significantly larger amount of thrombus was formed in the doubly-sealed grafts 4 h after reperfusion. It is reasonable to assume that increased acute thrombogenicity due to direct collagen-blood contact on graft surfaces is unfavourable to long term patency.

Animals↗
PubMed1991

Acute lower limb ischemia: failure of anticoagulant treatment to improve one-month results of arterial thromboembolectomy. A prospective randomized multi-center study.

The value of short-term anticoagulant treatment in improving the early outcome in patients operated on for acute lower-limb ischemia has been debated and so far unproven. In this prospective randomized multi-center study, 188 such patients were randomized on admission, either to preoperative and postoperative anticoagulant medication (AC group, n = 94) or no anticoagulant treatment during the first month after surgery (O group, n = 94). Background factors were evenly distributed in the two groups, and 89% of the cases were considered as embolic. Analysis on an intention-to-treat basis showed no differences in outcome after 30 days. Good results, survivors who had amputation, and patients who died in the two groups are given respectively: AC group, 61%, 9%, 30%; O group, 65%, 11%, 24%. The results were similar in the two treatment groups also if only patients with a cardiac source of embolism were analyzed. Local bleeding complications were more common in the AC group (17% vs 2%, p less than 0.01). It is concluded that preoperative and early postoperative anticoagulant medication should not be routinely administered since such treatment is unlikely to improve the short-term results of lower-limb arterial thromboembolectomy while bleeding complications increase. The possible value of late (beyond 1 month) long-term anticoagulant treatment remains to be studied.

Amputation, Surgical↗
PubMed1990

Venous endoscopy in thrombectomy of the iliac veins using the choledochoscope.

In the present communication venoscopy using a flexible choledochoscope is advocated after thrombectomy of the iliac veins. In 10 patients operated upon for occlusive thrombi in the pelvic veins, venoscopy was used to assess the status of the vein. The procedure was conveniently performed using a regular flexible choledochoscope. Venoscopy gave detailed information of the veins and lead to altered therapy in seven of the 10 patients. Venoscopy is recommended for intra-operative control during surgical thrombectomy and the use of a choledochoscope can simplify this procedure.

Endoscopes↗
PubMed1989

Effect of intravenous administration of corticosteroids on dentin formation in the adult rat molar.

This study describes the effects of intravenously given corticosteroids on dentin formation in adult rat molars. Six rats twice a day received corticosteroids 20 mg/kg for 8 days, 10 mg/kg for 13 days, and 5 mg/kg for 19 days. Six rats given a heterotopic heart transplant received 10 mg/kg of corticosteroids twice a day for 40-64 days. Six rats were used as controls. Tetracycline was given at the start of the experiment and after 3 wk of treatment. After 40-46 days the rats were killed. Light microscopic examination of the molars showed no differences in the dentin formation or in the predentin zone between the experimental and control rats. In the ultraviolet light microscope two lines of tetracycline were visible along the root canal walls in both experimental groups. There was an obvious distance between the two lines, which indicated formation of new dentin. In the control group no formation of dentin was visible.

Animals↗
PubMed1989

Intravenous leiomyomatosis.

A case of intravenous leiomyomatosis is presented along with a review of the literature. The condition is a neoplasia of smooth muscle originating from the uterus, with vermiform extensions into veins. Although histologically benign, the clinical course can be fatal if intravenous tumor progresses to the heart. Ordinary leiomyomas of the uterus are frequently coexistent. The symptoms are usually vague. The diagnosis should be suspected when a worm-like, greyish tumor with a smooth surface is found in cut vessels or when right-sided cardiac tumors are detected. Radical excision of the uterus and ovaries, as well as of the intravenous tumor extensions is recommended. In our case the tumor extended into the vena cava. The diagnosis was incidental during nephrectomy due to hydronephrosis. Tumor tissue was positive for estrogen and progesterone cytosolic receptors.

Diagnosis, Differential↗
PubMed1988

Rifampicin quinone is an immunosuppressant, but not rifampicin itself.

Rifampicin as a potential immunosuppressive agent was tested in the rat. A freshly made-up solution of this labile antibiotic in a daily dosage of 20 mg/kg iv did not affect mean graft survival time in a heterotopic heart transplant model. However, when stored solutions of rifampicin were used mean graft survival time was significantly prolonged (from 8.2 +/- 0.4 days with the controls to 18.1 +/- 1.2 days). A similar prolongation was observed when rifampicin quinone, the major rifampicin oxidation product, was administered. We conclude that the immunosuppressive effect ascribed to rifampicin is in fact due to its oxidation product, rifampicin quinone.

Animals↗
PubMed1986

The immunosuppressive effect of streptozotocin-induced diabetes in rats.

Streptozotocin-diabetic isogenous Brown-Norway (BN) rats received heterotopic Wistar-Furth (WF X BN) F1 heart transplants. The functional graft survival time after different duration of diabetes and during insulin-treated diabetes was recorded. Some diabetic rats were challenged with sheep red cells, and their spleens were used in PHA stimulation and plaque-forming assays. Prolongation in heart transplant survival was found to be independent of the duration of diabetes. The prolongation disappeared promptly when insulin was administered to the diabetic rats. A depression of cellular immunoresponsiveness as measured by PHA stimulation assay was recorded during diabetes. Valid results were not obtained in the plaque-forming assay.

Animals↗