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Biomedical subjects

J Link

Publications and source records attributed to J Link.

At least 109 records · Page 6Linked to original sources
PubMed1996

[CT and PRI angiographic findings in dissection of the neck arteries].

PURPOSE: To determine the usefulness of CT angiography (CTA) and MR angiography (MRA) for evaluation of dissection in cervical vessels. MATERIAL AND METHODS: Dissection of cervical vessels was revealed by conventional angiography in 4 patients (two female, two male) of 30-62 years of age. Dissection was located in the carotid artery (n = 3) and in the vertebral artery (n = 1). In two patients CTA and in two patients MRA was performed. RESULTS: Diagnosis of dissection was possible by CTA (internal carotid artery: n = 2) and by MRA (internal carotid artery and vertebral artery). Imaging of the dissection membrane of the vessel wall was possible in one case with MRA. CONCLUSION: CT and MR angiography was successful for detection of typical morphology of dissection in all cases. If results in a greater number can be obtained it seems to be conceivable that both methods can be used in primary diagnosis.

Adult↗
PubMed1996

[Spiral CT angiography versus DSA in detection of carotid stenoses].

PURPOSE: To determine the value of spiral CT angiography for evaluation of internal carotid artery stenosis. METHODS: Spiral CT angiography was compared with selective intraarterial DSA in 40 patients with 72 internal carotid artery stenoses. Quantification of stenoses was performed according to the NASCET-study and categorized in mild (0-29%), moderate (30-69%), severe (70-99%) and occlusion (100%). RESULTS: The total agreement of spiral CT angiography with DSA in all stenoses was 78% (r = 0.933; p < 0.0001). In the mild stenoses group there was an agreement of 56% (r = 0.598; p = 138), in the moderate stenosis group there was an agreement of 59% (0.623; p = 0.0128) and in the group with severe stenosis the agreement was 97% (0.944; p < 0.0001). All occlusions were correctly interpreted by spiral CT angiography (r = 1; p = 0.0082). CONCLUSION: The agreement of spiral CT angiography with DSA is good. Especially SCTA allows a good correlation in the severe stenosis group and in the occlusion group. DSA remains the standard of reference, because of its ability to demonstrate tandem lesions and collateral flow.

Adult↗
PubMed1995

Increased mRNA expression of IL-6, IL-10, TNF-alpha, and perforin in blood mononuclear cells in human HIV infection.

Evidence has been presented for the involvement of various cytokines, including interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-alpha, in the pathogenesis of human immunodeficiency virus (HIV) infection. Since measured plasma levels may poorly reflect in vivo production of cytokines, we adopted in situ hybridization with cDNA oligonucleotide probes to enumerate blood mononuclear cells (MNCs) expressing mRNA for IL-6, IL-10, TNF-alpha, and perforin. The HIV-infected patients had elevated levels of MNCs expressing mRNA for all four cytokines compared to healthy controls. Numbers of IL-6 mRNA-expressing cells were higher in patients with clinical AIDS than in asymptomatic seropositive patients, and correlated inversely with CD4+ cell counts in blood, reflecting the involvement of IL-6 in later stages of HIV infection. The described approach could be an alternative way to study cytokines in HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Screening and kinetic analysis of recombinant anti-CEA antibody fragments.

Four different carcinoembryonic antigen (CEA)-binding antibody fragments were prepared using the genes of the variable regions of the T84 epitope-specific antibody 7F7 and phage display techniques. The genes were successfully cloned and expressed in the pCANTAB5 phage display vector to investigate the kinetic binding parameters of each synthesized construct. Single chain fragments, Fab fragments, and two diabodies were purified and compared in their CEA-binding properties with the parent IgG using surface plasmon resonance detection. The on-rates for all these molecules were in the same order of magnitude (about 1 x 10(5) M-1 s-1) whereas major differences were detected in the off-rates. IgG and diabodies had slow off-rates due to bivalent binding, while single chain and Fab fragments dissociated rather fast. We also present a method for the immobilization of large amounts of CEA on CM5 sensorchips. These high density surfaces can be used for observing mass transport limited binding of CEA-specific molecules and are convenient tools for screening and quality control.

Antibody Affinity↗
PubMed1995

Excessive hypokalemia and hyperkalemia following head injury.

A sudden decrease of serum potassium below 2.5 mmol/l carries the risk of dangerous arrhythmias and requires immediate replacement therapy [6]. We refer to a patient with a brain stem compression after head injury, who developed a profound hypokalemia (K+ = 1.2 mmol/l) with life-threatening arrhythmias, probably due to a catecholamine induced intracellular potassium shift (beta-2-stimulation). Only by aggressive potassium replacement up to 80 mmol/h (610 mmol/16 h) could potassium levels be increased and cardiac arrhythmias terminated. Although replacement therapy was stopped when the serum K(+)-level increased to 2.4 mmol/l, 3.5 h later the patient became hyperkalemic (8.1 mmol/l). This was probably due to a secondary shift of potassium from intra- to extracellular space. In patients with severe head trauma and the potential risk of excessive catecholamine release special attention must be paid to changes in potassium balance.

Craniocerebral Trauma↗
PubMed1995

[Loss of brain stem auditory evoked potential waves I and II during controlled hypotension].

For surgical removal of a malignant choroid melanoma, it is necessary to reduce systolic blood pressure to around 50-60 mmHg in order to prevent choroidal haemorrhages. However, blood pressure reduction is associated with the risk of cerebral ischaemia. We report a patient with a malignant choroid melanoma in whom waves I and II of the brainstem auditory evoked potentials (BAEP) disappeared during surgery under controlled arterial hypotension and hypothermia (31.1 degrees C). The waves could be recorded again immediately after the mean arterial pressure was increased from 48 to 77 mmHg. The oesophageal temperature had dropped by 0.3 degrees C at this time. The 2-channel electroencephalogram (EEG) showed no irregularities during this time period. A bilateral, reversible, apparently blood-pressure-dependent loss of waves I and II during arterial hypotension despite a normal EEG has to our knowledge not been previously described in the literature. The isolated loss of waves I and II with maintenance of waves III, IV, and V is unusual. The literature contains reports of acoustic neurinoma patients in whom only wave V could be recorded. This is regarded as an indication of continued impulse conduction despite the loss of waves I to IV. Others have observed a patient with temporary and reversible loss of BAEP wave I due to vasospasm of the internal auditory artery that apparently occurred during or shortly after manipulation of the internal auditory meatus. Assuming anatomic peculiarities in the blood supply to the generators of the BAEP waves, a stenosis of the basilar artery could be considered as the cause of the bilateral reversible loss of waves I and II. Another potential source could be induced hypothermia, but this does not seem very likely because the patient's temperature was 0.3 degrees C lower at the return of the waves than at their loss.

Choroid Neoplasms↗
PubMed1995

Transforming growth factor-beta 1 suppresses autoantigen-induced expression of pro-inflammatory cytokines but not of interleukin-10 in multiple sclerosis and myasthenia gravis.

Multiple sclerosis (MS) is associated with high levels of circulating T lymphocytes that respond to the myelin antigens myelin basic protein (MBP) and proteolipid protein (PLP) by producing various cytokines including interferon-gamma (IFN-gamma) that makes MS worse and transforming growth factor-beta (TGF-beta), an endogenously produced immunosuppressant that might act beneficially. To further define the role of TGF-beta in MS, we examined the effects of recombinant TGF-beta 1 (rTGF-beta 1) on autoantigen-mediated regulation of cytokines in MS and myasthenia gravis (MG). Blood mononuclear cells (MNC) were cultivated with or without rTGF-beta 1, and with or without autoantigen or the recall antigen PPD. MNC expressing cytokine mRNA were detected after in situ hybridization with radiolabeled cDNA oligonucleotide probes. Femtogram concentrations of rTGF-beta 1 suppressed MBP-, PLP- and PPD-induced upregulation of IFN-gamma, IL-4, IL-6, tumor necrosis factor-alpha (TNF-alpha), TNF-beta and perforin in MS, and acetylcholine receptor (AChR)-induced augmentation of these pro-inflammatory cytokines in MG, but had no effects on autoantigen- or PPD-induced expression of IL-10 or TGF-beta itself. rTGF-beta 1 also suppressed numbers of myelin antigen-reactive IFN-gamma- and IL-4-secreting cells in MS and AChR-reactive IFN-gamma and IL-4 secreting cells in MG. The selective suppressive effects of TGF-beta 1 on autoantigen-induced upregulation of pro-inflammatory cytokines makes TGF-beta 1 attractive as a treatment alternative in MS and MG.

Adult↗
PubMed1995

Suppression of experimental autoimmune myasthenia gravis by nasal administration of acetylcholine receptor.

Experimental autoimmune myasthenia gravis (EAMG) is a well established animal model, which can be induced in various animal species and strains with acetylcholine receptor (AChR) and represents an experimental counterpart of human myasthenia gravis (MG). Current immunotherapies of both EAMG and MG are non-specific and limited by their toxicity. Tolerance to EAMG has been achieved by oral administration of milligram quantities of Torpedo AChR. In the present report we demonstrate that nasal administration of microgram doses of Torpedo AChR to female Lewis rats prior to immunization with Torpedo AChR and complete Freund's adjuvant resulted in the prevention of subsequently induced EAMG, the suppression of serum anti-AChR antibody levels, the decrease of delayed-type hypersensitivity responses to AChR, as well as the suppression of AChR-specific immunoglobulin G-secreting cells, AChR-reactive interferon-gamma-secreting cells and T cell proliferation in peripheral lymphoid organs, particularly in popliteal and inguinal lymph nodes regional to immunization. We conclude that clinical signs of EAMG can be efficiently prevented by nasal administration of AChR in parallel with the downregulation of both B and T cell responses specific to AChR.

Administration, Intranasal↗
PubMed1995

[The importance of sonography before laparoscopic cholecystectomy].

The increasing use of minimally invasive techniques for the treatment of symptomatic cholecystitis requires exact preoperative diagnosis. The significant sonographic findings are stones in the biliary system or indirect evidence of stones, consisting in dilatation of the bile duct to more than 10 mm, as well as free mobility of the abdominal wall to exclude peri-umbilical adhesions. Amongst 100 patients who had laparoscopic cholecystectomies there were 7 with bile ducts wider than 10 mm. In two of these cases calculi could also be demonstrated. ERCP was performed on the remaining five and in 3 of these stones were seen. Peri-umbilical adhesions were seen in 6 Patients, resulting in alternative placing of the incision. The sonographic findings which are of relevance to the surgeon were analysed in these 100 cases. A standardised examination protocol is an important feature for proper patient selection.

Adolescent↗
PubMed1995

[The initial results of spiral CT angiography in demonstrating stenoses of the a. carotis].

PURPOSE: To determine the value of spiral CT angiography in Maximum Intensity Projection (MIP)-technique for evaluation of carotid artery stenosis. METHODS: A comparison of the MIP technique with intraarterial DSA was done in 24 patients with 40 stenoses. Quantification of stenosis was determined according to the NASCET study: mild (0-29%), moderate (30-69%), severe (70-99%) and occlusion (100%). RESULTS: Totally the correlation of spiral CT angiography with DSA was 80% (r = 0.93; p = 0.0001). In the moderate stenosis group (r = 1; p = 0.1573), severe stenosis group (r = 0.89; p = 0.002) and the occlusion group (r = 1; p = 0.0009) there was a good correlation with DSA. In the mild stenosis group (r = 0.55; p = 0.0704) correlation of spiral CT angiography with DSA was poor. Spiral CT angiography allows an excellent delineation of calcifications. Tandem lesions and collateral flow cannot be shown with spiral CT angiography. CONCLUSION: Intraarterial DSA remains the gold standard for evaluation of carotid artery stenosis, because DSA is the modality which shows the whole length of the carotid artery and yields information on tandem lesions and collateral flow.

Adult↗
PubMed1995

[Venous stent application with a simultaneous cubitofemoral approach].

In 4 patients with superior inflow obstruction caused by stenosis or occlusion of the central veins it was not possible to pass the guide wire from transfemoral. An additional transbrachial access was applied to avoid the stenosis or occlusions. Patency of the veins from transbrachial was achieved in all cases. After pulling the extensively long guide wire through the still horizontal venous lock, successful Wallstent application was performed from transfemoral in all 4 patients. No peri-interventional or post-interventional complications were seen during 2 days follow-up.

Aged↗
PubMed1995

[CT angiography in the follow-up after carotid endarterectomy].

PURPOSE: To prove the usefulness and clinical value of early CT angiography with maximum intensity projection after carotid endarterectomy: for demonstrating postoperative results. METHODS: In 16 patients with angiographically confirmed 20 high grade stenoses of internal carotid artery CT angiography was performed before and after carotid surgery within 7 days. The evaluation of successful surgery was related to complete plaque removal and patency of internal carotid artery after endarterectomy based on preoperative CT angiography. Classification of stenosis was performed according to the NASCET study. RESULTS: In 2/20 cases severe stenoses remained after surgery, which were demonstrated using CT angiography and confirmed by digital subtraction arteriography. 3/20 cases showed mild stenosis and 15/20 were normal. CONCLUSION: CT angiography is best suited to evaluate results after carotid surgery. The method enables delineation of complete removal of calcified plaque and patency of carotid artery.

Aged↗
PubMed1995

[A modified technic for local rt-PA catheter-mediated lysis].

PURPOSE: To develop an economic and efficient concept for more time-saving local rt-PA thrombolysis therapy. METHOD: 40 patients with peripheral vascular occlusive disease stage IIb-III according to the Fontaine classification and with angiographically proven occluded segments of pelvic and lower limb arteries were treated by a modified concept of local rt-PA catheter thrombolysis. Via a thin guide wire the catheter for thrombolysis is slowly advanced through the thrombus without fluoroscopic control, outside the room in which angiography is performed. In 24 cases a short-term lysis and in 16 cases a long-term lysis was carried out. RESULTS: The initial success rate was 75%, the patency rate in six months' follow-up was 66.7%. The ankle-brachial index decreased from 0.4 +/- 0.3 to 0.8 +/- 0.2 on the average. There were no relevant clinical complications. The average occupancy time of the angiography room or table was 60 +/- 52 min, the average time of fluoroscopy was 17 +/- 13 min. CONCLUSION: In modified local rt-PA thrombolysis, short-term lysis and long-term lysis were mostly performed outside the angiography room, so that the exposure to radiation and there fore the radiation dose were reduced for both the patient and the attending staff. The angiography room is thus available for other patients and can therefore be used more efficiently.

Adult↗
PubMed1995

Theoretical considerations and in vitro results for the development of percutaneous transcatheter balloon embolectomy.

RATIONALE AND OBJECTIVES: To prove the feasibility of performing percutaneous transcatheter embolectomy using a funnel-shaped catheter tip and balloon embolectomy catheters. METHODS: A theoretical model is described to assess the influence of the diameter of an introductory device and coaxially introduced embolectomy catheter. A funnel-shaped catheter tip was attached to 7F, 8F, and 9F introductory sheaths. In vitro embolectomy of 5 g and 12 g thrombi was performed with 3F and 4F embolectomy catheters. RESULTS: The number of extractions required was significantly related to the ratio of the diameters of the sheaths and embolectomy catheter shafts. The combination of a 7F sheath with a 4F embolectomy catheter required the greatest number of extractions (8.4 +/- 1.7). The least number of extractions was needed for the combination of a 9F sheath with 4F and 3F embolectomy catheters (1.6 +/- 0.7 and 1.8 +/- 0.4, respectively). CONCLUSIONS: Our results indicate that percutaneous embolectomy with balloon embolectomy catheters is feasible. However, further research is necessary before the final catheter design is chosen.

Catheterization↗
PubMed1995

High numbers of autoantigen-reactive mononuclear cells expressing interferon-gamma (IFN-gamma), IL-4 and transforming growth factor-beta (TGF-beta) are present in cord blood.

Umbilical cord blood of neonates and peripheral blood of healthy adults were analysed by in situ hybridization for numbers of mononuclear cells (MNC) expressing the cytokines IFN-gamma, TGF-beta and IL-4 mRNA without culture and after culture in the presence of acetylcholine receptor (AChR), myelin basic protein (MBP) and peripheral myelin protein P2. These antigens were chosen since they represent autoantigens in putatively immune-mediated neurological diseases. The numbers of cells expressing cytokine mRNA after 72 h culture in the presence of AChR, MBP and P2 were higher in cord blood than in peripheral blood of healthy adults. IFN-gamma, TGF-beta and IL-4 were always elevated in parallel. In cord blood there was a pronounced reactivity to several of the tested antigens, while such broad reactivity was not found in peripheral blood of healthy adults. No differences in cytokine mRNA expression were found between cord blood and peripheral blood of adults when cells were analysed without culture. The results show a capacity of cord blood cells to react to several autoantigens by the up-regulation of cytokine mRNA expression.

Adult↗
PubMed1995

Increased mRNA expression of IL-10 in mononuclear cells in multiple sclerosis and optic neuritis.

The inflammatory nature of multiple sclerosis (MS) implicates the participation of immunoregulatory cytokines, including the Th2 related IL-10. We describe the use of in situ hybridization with cDNA oligonucleotide probes to detect and enumerate mononuclear cells (MNC) expressing mRNA for IL-10, which is known to down-regulate Th1 cell related cytokines such as interferon-gamma. Expression of IL-10 was studied in blood MNC of MS and blood and cerebrospinal fluid (CSF) MNC of optic neuritis (ON) patients without culture and after culture in the presence of myelin basic protein (MBP), the control antigen acetylcholine receptor (AChR), and without antigen. Numbers of IL-10 mRNA expressing MNC were elevated in the MS patients' blood both when enumerated without culture and after culture with MBP. Control patients with myasthenia gravis had elevated numbers of AChR-reactive IL-10 mRNA expressing cells, while numbers of MBP-reactive IL-10 positive cells did not differ from numbers registered in cells without antigen. Patients with ON, in many instances representing early MS, had IL-10 positive blood MNC that were elevated to the same extent as in clinically definite MS, and further increased in the CSF. ON patients examined within 1 month after onset had lower numbers of MBP induced IL-10 mRNA expressing blood MNC compared with patients examined later suggesting that IL-10 is related to the degree of inflammation and outcome in ON.

Adolescent↗