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Biomedical subjects

J Link

Publications and source records attributed to J Link.

At least 127 records · Page 7Linked to original sources

Cytokine mRNA profiles in mononuclear cells in acute aseptic meningoencephalitis.

Cytokines are important modulators of inflammation and immune responses. Using in situ hybridization with radiolabelled cDNA oligonucleotide probes, we studied the expression of mRNA encoding the cytokines gamma interferon (IFN-gamma), interleukin 4 (IL-4), IL-6, IL-10, transforming growth factor beta (TGF-beta), tumor necrosis factor alpha (TNF-alpha), lymphotoxin, and perforin in mononuclear cells (MNC) from blood and cerebrospinal fluid (CSF) of patients with acute aseptic meningoencephalitis (AM) and from blood of healthy controls. Patients in the acute phase of AM had elevated numbers of IFN-gamma mRNA-expressing cells in the blood compared with that of controls and higher numbers of IFN-gamma mRNA-expressing cells in their CSF compared with that of convalescent-phase patients, which is in accordance with the antiviral effects of this cytokine. Upregulation of IL-4, IL-6, and IL-10 was found in convalescent-phase patients, which is consistent with the longstanding B-cell response found in AM. TGF-beta and perforin were upregulated in both stages of AM, while the numbers of blood and CSF MNC expressing cytokine mRNA of the TNF family (TNF-alpha and lymphotoxin) did not differ between patients with AM and controls. An even higher elevation in CSF was noticed for MNC expressing most of the cytokines, particularly IL-4 and TGF-beta, reflecting the autonomy of the immune response in the CSF. The definition of cytokine profiles in AM, a self-limiting and benign disease, provides a foundation for future comparisons with other infectious and inflammatory nervous system diseases.

Acute Disease↗

Expression of IFN-gamma, IL-4, and TGF-beta in multiple sclerosis in relation to HLA-Dw2 phenotype and stage of disease.

Multiple sclerosis (MS) is associated with upregulation of both proinflammatory (interferon-gamma, IFN-gamma) and immunosuppressive (transforming growth factor-beta, TGF-beta) cytokines. To examine a possible relation between the MS-related HLA haplotype Dw2 and cytokine profiles, we used in situ hybridization with labeled cDNA oligonucleotide probes to detect transcripts of the T helper type 1 (Th 1) cell related IFN-gamma, the Th2 cell related interleukin-4 (IL-4) and of TGF-beta in blood and cerebrospinal fluid (CSF) mononuclear cells from 62 patients with MS. Compared to patients with other neurological diseases and healthy controls, MS patients had elevated numbers of IFN-gamma, IL-4 and TGF-beta mRNA expressing cells in blood and further augmented in CSF. Although several HLA-Dw2-positive individuals showed very high numbers of cells expressing these cytokines, no significant difference was found in comparison with Dw2-negative patients. However, expression of IL-4 and TGF beta mRNA was significantly increased in patients with shorter duration and minor disability and, for IL-4, in patients still in the relapsing-remitting phase compared to patients with secondary chronic progressive MS. Surprisingly, these changes which favour a beneficial, disease-downregulating effect of IL-4 and TGF-beta in MS, were found to be confined to HLA-Dw2-positive patients. Our findings suggest that the HLA phenotype does not influence the overall level of immune reactivity in MS, but may distinguish subgroups characterized by particular cytokine expression patterns.

Adolescent↗

[Spiral CT of the thorax with double table feed in relation to slice thickness].

PURPOSE: The aim of the study was to reduce investigation time, radiation dose, and contrast material when performing spiral-CT of the thorax. METHODS: 50 patients with different clinical diagnoses underwent spiral-CT of the thorax with double table feed and 45 ml contrast material (lopentol) were injected. Density measurements were performed as follows: main pulmonary artery without contrast injection, carotid artery, subclavian artery, ascending and descending aorta, aortic arch, main pulmonary artery and thoracic aorta after contrast injection. RESULTS: In comparison to the density of the main pulmonary artery without contrast injection there was an increase of density of 134 HU. 45 ml of the contrast agent were sufficient in all cases for delineation of the mediastinal vessels. Investigation time was 16-18 s and all patients were able to hold their breath during this time, so no artifacts were seen. Radiation dose was cut in half. CONCLUSION: Spiral-CT with double table feed enables investigations of the thorax in less than 20s. 45 ml of a contrast agent are sufficient for performing this examination. There are no essential diagnostic deficits with this technique.

Absorptiometry, Photon↗

Concepts and diagnosis of brain death.

The different concepts of brain death are subject to controversial debate. It is outlined that only the whole-brain concept, that is the irreversible loss of all functions of the entire brain, is consistent with the death of man. Cortical death or brain-stem death should not be considered in this respect. The operational procedure for determining brain death is outlined with special regard to those cases in which a definite diagnosis cannot be made clinically. It is shown that apnea testing must be accompanied by blood-gas analysis, as it may take 15 min for the PaCO2 to achieve the desired level of 8 kPa. The problem with CNS-depressing drugs and their metabolites interfering with the clinical diagnosis--e.g. sedatives, barbiturates, opioids--is described, and it is stressed that, in these cases, the cerebral panangiography (digital subtraction angiography with catheter tip in the aortic arch) is the gold standard for the final and definite proof of brain death.

Brain Death↗

Organ-specific autoantigens induce transforming growth factor-beta mRNA expression in mononuclear cells in multiple sclerosis and myasthenia gravis.

Multiple sclerosis (MS) is characterized by patchy accumulations of inflammatory cells combined with demyelination. There are mononuclear cells in blood and cerebrospinal fluid of patients with MS that produce interferon-gamma and interleukin-4 in response to myelin basic protein (MBP) and proteolipid protein (PLP). Here we describe autoantigen-induced production of transforming growth factor-beta (TGF-beta). This multifunctional cytokine has inhibitory effects on the growth, differentiation, and effector functions of activated T cells. Blood and cerebrospinal fluid cells were exposed in short-term cultures to MBP and PLP and, after hybridization with complementary DNA oligonucleotide probes, they were evaluated for TGF-beta mRNA expression. Patients with MS had higher numbers of MBP- and PLP-responsive TGF-beta mRNA expressing cells in blood compared with control patients with other neurological diseases or myasthenia gravis and a five- and threefold further increment in their cerebrospinal fluid. In blood of patients with myasthenia gravis, where the acetylcholine receptor (AChR) is a target for autoaggressive immunity, there were increased levels of AChR-responsive TGF-beta mRNA expressing cells. Thymectomized myasthenia gravis patients showed higher levels of TGF-beta mRNA expressing cells compared with patients not thymectomized. Numbers of cells responding to AChR in MS and MBP in myasthenia gravis did not differ from numbers found in absence of antigen. Patients with other neurological diseases showed infrequent and low responses to MBP, PLP, and AChR. Diseases with presumed autoimmune pathogenesis are associated with organ-specific autoantigen-induced TGF-beta production, which is increased after thymectomy.

Adult↗

Increased transforming growth factor-beta, interleukin-4, and interferon-gamma in multiple sclerosis.

The inflammatory nature of multiple sclerosis (MS) implicates the participation of immunoregulatory cytokines, including the T-helper type 1 (Th1) cell-associated interferon-gamma (IFN-gamma), the Th2 cell-related interleukin-4 (IL-4), and the immune response-downregulating cytokine transforming growth factor-beta (TGF-beta), but proof for their involvement in MS has been lacking. By adopting in situ hybridization with complementary DNA oligonucleotide probes for human IFN-gamma IL-4, and TGF-beta, the expression of mRNA for these cytokines was detected in mononuclear cells (MNC) from blood and cerebrospinal fluids. Strongly elevated levels of MNC expressing all three cytokines were found in peripheral blood and at even higher frequencies in cerebrospinal fluid from untreated patients with MS and optic neuritis, i.e., a common first manifestation of MS, compared with patients with other neurological diseases and healthy subjects. In MS and optic neuritis, IL-4 mRNA expressing cells predominated, followed by TGF-beta- and IFN-gamma-positive cells. Control patients with myasthenia gravis had similarly elevated levels of IFN-gamma and TGF-beta and TGF-beta mRNA expressing blood MNC but lower numbers of IL-4-positive cells. No or slight disability of MS was associated with high levels of TGF-beta mRNA expressing cells, while MS patients with moderate or severe disability had high levels of IFN-gamma-positive cells. IFN-gamma and TGF-beta may have opposing effects in MS, and treatments inhibiting IFN-gamma and/or promoting TGF-beta might ameliorate MS.

Adult↗

Induction of interferon-gamma, interleukin-4, and transforming growth factor-beta in rats orally tolerized against experimental autoimmune myasthenia gravis.

Oral administration of nicotinic acetylcholine receptor (AChR) to Lewis rats prior to myasthenogenic immunization with Torpedo AChR+complete Freund's adjuvant (CFA) results in the prevention of experimental autoimmune myasthenia gravis (EAMG) and the suppression of AChR-specific B cell responses and counteracts the development of AChR-reactive interferon-gamma (IFN-gamma) secreting T cells. To study the involvement of the T helper type 1 (Th1) cell-related lymphokine IFN-gamma, the Th2 cell-related interleukin-4 (IL-4), and transforming growth factor beta (TGF-beta) that suppresses the synthesis of IFN-gamma and IL-4, we used in situ hybridization with complementary DNA oligonucleotide probes to enumerate mononuclear cells (MNC) expressing mRNA for the cytokines IFN-gamma, IL-4, and TGF-beta. Upon in vivo recognition of AChR, popliteal, inguinal, and mesenteric lymph nodes, spleen and thymus of rats with EAMG contained higher levels of IFN-gamma, IL-4, and TGF-beta mRNA-expressing cells compared to CFA-injected control rats, implicating the involvement in EAMG of AChR-reactive Th1 and Th2 cells in parallel. TGF-beta was also upregulated in EAMG. Oral tolerance to EAMG was characterized by suppression of the levels of MNC expressing IFN-gamma and IL-4, but augmentation of cells expressing TGF-beta. The results suggest that IFN-gamma, IL-4, and TGF-beta are involved in the development of EAMG, and that TGF-beta is important in the induction of oral tolerance to EAMG.

Animals↗

The receptor for urokinase-type plasminogen activator of a human keratinocyte line (HaCaT).

It is assumed that plasmin participates in pericellular proteolysis in the epidermis. Plasmin is generated by keratinocyte-associated plasminogen activators from the proenzyme plasminogen; plasminogen activation can proceed at the keratinocyte surface. The resultant plasmin interferes with cell to matrix adhesion and does possibly contribute to keratinocyte migration during reepithelialization. Here we describe the receptor for urokinase-type plasminogen activator (uPA-R) in the human keratinocyte cell line HaCaT, which serves to direct plasminogen activation to the cell surface; we relate the receptor to the uPA-R previously described in human myelo-/monocytes. Binding of uPA to the receptor accelerated plasminogen activation by a factor of approximately 10, compared to uPA in solution. Receptor-bound uPA was susceptible to inhibition by the plasminogen activator inhibitors 1 and 2. uPA and uPA-R antigen, as well as uPA activity, were localized to the leading front of expanding sheets of HaCaT cells. Exposure of HaCaT cells to plasminogen was followed by detachment of the cells. Detachment was prevented by an anticatalytic anti-uPA antibody, by the plasmin-specific inhibitor aprotinin, and by the lysine analogue tranexamic acid, the latter of which prevents plasmin(ogen) binding to the cell surface. Our findings support the hypothesis that uPA-mediated plasminogen activation is characteristic of mobile rather than sessile keratinocytes. Moreover, the uPA-R seems to focalize plasminogen activation to the surface of cells at the site of keratinocyte migration.

Base Sequence↗

[PTFE prostheses in infrarenal aneurysms of the abdominal aorta].

Postoperative dilatation of Dacron vascular grafts can lead to aneurysms and rupture of the prosthesis making it necessary to change the graft by operation. Therefore, 15 patients at Lübeck University Hospital underwent replacement of the aorta with PTFE prostheses due to infrarenal aortic aneurysms. Ultrasound measurements 2-12 months postoperatively revealed a dilatation of 11.6% concerning tubular grafts, 11.5% for the shafts and 14.6% for the limbs of bifurcation grafts compared to the higher dilatation rate of Dacron prostheses described in the literature. There was no evidence of anastomotic false aneurysms, thrombosis of the limbs of bifurcation grafts, peripheral embolization or perigraft reaction. In conclusion, PTFE prostheses seem to be a means of preventing patients from having secondary complications as a result of graft dilatation. Based on our early results and the results described in the literature, PTFE prostheses can be regarded as an alternative to dacron prostheses.

Aged↗

Venous and paradoxical air embolism in the sitting position. A prospective study with transoesophageal echocardiography.

This prospective study investigates the frequency of patent foramen ovale (PFO), venous air embolism (VAE) and paradoxical air embolism (PAE) by transoesophageal echocardiography (TOE) in neurosurgical patients operated on in the sitting position. The risk of PAE after exclusion of PFO is assessed. A PFO was identified by pre-operative TOE and VAE and PAE by continuous intraoperative TOE. Sixty-two patients were divided into two groups, 22 patients were studied in group 1 (posterior fossa surgery) and group 2 (cervical surgery) contained 40 patients. Pre-operative TOE demonstrated a PFO in 5 of the 22 patients in group 1 (23%). Patients with proven PFO were excluded from the sitting position. Two further patients of this group (12% of 17 patients), in whom a PFO had been excluded pre-operatively, nevertheless had PAE, air occurring in all cavities of the heart. In group 2 the incidence of PFO was 4 out of 40 patients (10%). No PAE was observed in this group. Three morphological types of VAE with different haemodynamic and ventilation changes were demonstrated. VAE was observed in 76% of all posterior fossa operations and in 25% of cervical laminectomies. We conclude that a pre-operative search for PFO is mandatory considering its incidence of 23% in group 1 and of 10% in group 2, and the risk of PAE. If a PFO is detected, the sitting position should be avoided. A residual risk for PAE remains despite exclusion of PFO because the reliability of TOE is limited. TOE is the method of choice for detecting VAE and PAE.

Adult↗

Augmented interferon-gamma, interleukin-4 and transforming growth factor-beta mRNA expression in blood mononuclear cells in myasthenia gravis.

The abnormal T lymphocyte-dependent production of antibodies to the nicotinic acetylcholine receptor (AChR) in myasthenia gravis (MG) suggests a role for immunoregulatory cytokines. We examined the T helper type 1 (Th1) cell-associated interferon-gamma (IFN-gamma) that promotes cell-mediated immunity, the Th2 cell-related interleukin-4 (IL-4) that augments B cell immunity, and transforming growth factor-beta (TGF-beta) that downregulates immune responses but enhances isotype switching. Blood mononuclear cells (MNC) expressing cytokine mRNA were enumerated after in situ hybridization with labelled complementary DNA oligonucleotide probes for IFN-gamma, IL-4 and TGF-beta. MG patients had elevated numbers of cells expressing IFN-gamma and IL-4 compared to patients with non-inflammatory neurological diseases and healthy controls, implying that both Th1- and Th2-like cells are involved in MG. TGF-beta-positive cells were also elevated in MG. The levels of cytokine-positive MNC were similar in MG and in control patients with other inflammatory neurological diseases. There were no associations between numbers of cytokine-positive blood MNC and clinical variables of MG, but individual patients need to be studied over the course of MG to clarify a relation between the cytokines under study and clinical or laboratory variables of MG.

Adolescent↗

Optic neuritis is associated with myelin basic protein and proteolipid protein reactive cells producing interferon-gamma, interleukin-4 and transforming growth factor-beta.

Studies on patients with monosymptomatic optic neuritis (ON) should give opportunities to identify features typical for early multiple sclerosis (MS). There are increased T and B cell responses to the myelin components myelin basic protein (MBP) and proteolipid protein (PLP) in both ON and MS, but there is little information on the types of cytokines produced by such cells. We describe the use of in situ hybridization with complementary DNA oligonucleotide probes to detect and enumerate mononuclear cells expressing mRNA for the cytokines interferon-gamma (IFN-gamma) which augments cell-mediated immunity; interleukin-4 (IL-4) which promotes the B cell response; and transforming growth factor beta (TGF-beta) that in many cases downregulates immune responses. Expression of these cytokines was studied in mononuclear cells from peripheral blood and cerebrospinal fluid (CSF) from patients with ON and MS after in vitro exposure to MBP and PLP, and in absence of antigen. There were elevated levels of cells that in response to MBP and PLP expressed IFN-gamma, IL-4 and TGF-beta mRNA in blood and further enriched in CSF in both ON and MS, compared to patients with other neurological diseases. The results suggest that IFN-gamma, IL-4 as well as TGF-beta are involved in both ON and MS, and that the cytokine profile in early MS as reflected by ON is not different from that in clinically definite MS.

Adult↗

Water transport in concrete.

Chloride contamination is a major source of concrete deterioration. Previous studies of chloride transport use weight-vs.-time analysis on immersed samples to deduct related concrete water exchange properties, based on the assumptions of strictly capillary flow and a well defined transport front. The calculations yield substantially higher penetration depths than are found empirically. MRI was used to tomographically follow the water uptake and check the validity of these model assumptions. To eliminate background signal from enclosed water, we worked with deuterated water in combination with deuterium MRI. This approach provides evidence for a reduced water exchange depth and for its dependence on prestorage conditions, and suggests refinements to the previously used concrete model.

Construction Materials↗

[The value of pneumo-arthro-CT in diagnosis after traumatic shoulder dislocation].

Traumatic subluxation of the shoulder in young patients may result in reluxation after further injury. 18 patients with traumatic subluxation and 22 patients with recurrent subluxation of the shoulder (after primary trauma) were examined by arthroscopy and pneumo-arthro-CT. This minimally invasive procedure showed high accuracy in the diagnosis of the typical glenoid margin and humoral head abnormalities. Nevertheless, arthroscopy cannot be abandoned for planning suitable operative treatment.

Adolescent↗

[DSA with mechanically injected carbon dioxide. Animal experimental results].

Carbon dioxide was used as an intra-arterial contrast medium by mechanical injection in 10 pigs. 127 angiographic examinations of 114 vascular territories were carried out and 93 were successful. A mechanism providing even gas volumes was chosen to obtain reproducible volume and pressures when using a compressible medium such as gas. Gas pressure is exponentially correlated with volume and volumes of 20-50 cm3 at 1000 mbar adequate for filling various infradiaphragmatic vascular areas. In parenchymatous organs, gas filling is seen only as far as third order arteries. The reason for this is escape of gas through preexisting arteriovenous fistulae into the efferent veins.

Angiography, Digital Subtraction↗

Increased levels of interferon-gamma (IFN-gamma), IL-4 and transforming growth factor-beta (TGF-beta) mRNA expressing blood mononuclear cells in human HIV infection.

Evidence has been presented for the involvement of IFN-gamma, IL-4 and TGF-beta in AIDS. Measured plasma levels may, however, poorly reflect in vivo production, since cytokines act auto- and paracrinally and have very short half life in plasma. In situ hybridization with complementary DNA oligonucleotide probes was used to enumerate blood mononuclear cells expressing cytokine messenger RNA (mRNA). HIV-infected patients had elevated blood levels of cells expressing each of the cytokines, with predominance for cells expressing TGF-beta mRNA. All AIDS patients included had elevated numbers of IL-4 mRNA-expressing cells, and levels of cells expressing this cytokine correlated inversely with counts of CD4+ cells in blood, reflecting the involvement of Th2-like cells in later stages of HIV infection. The described approach should be useful in further studies of cytokines in HIV infection and other diseases.

Adult↗

Organ-specific autoantigens induce interferon-gamma and interleukin-4 mRNA expression in mononuclear cells in multiple sclerosis and myasthenia gravis.

T cells recognizing the myelin components myelin basic protein (MBP) and proteolipid protein (PLP) are increased in multiple sclerosis (MS), and there are elevated numbers of T cells recognizing the nicotinic acetylcholine receptor (AChR) in myasthenia gravis (MG). However, the cytokine repertoires in these diseases are largely unknown. We adopted in situ hybridization with radiolabeled complementary DNA oligonucleotide probes to enumerate mononuclear cells that expressed the T-helper type 1 (Th1) cell-related interferon-gamma (IFN-gamma) and Th2-associated interleukin-4 (IL-4) after short-term culture in the presence of autoantigen. High numbers of IFN-gamma and IL-4 mRNA-expressing cells in response to MBP and PLP were detected in patients with untreated MS, and to AChR in MG. The levels of IFN-gamma and IL-4 mRNA-positive cells in MS after culture in the presence of AChR, and in MG after culture in the presence of MBP or PLP, did not differ from those detected after culture without antigen. The CSF of MS patients contained four- to eightfold more myelin protein-reactive IFN-gamma and IL-4 expressing cells. The findings imply that MS and MG are associated with mixed Th1- and Th2-like cell responses directed to organ-specific target antigens.

Adult↗

Interferon-gamma, interleukin-4 and transforming growth factor-beta mRNA expression in multiple sclerosis and myasthenia gravis.

BACKGROUND: Multiple sclerosis (MS) is characterized by perivascular inflammation and high levels of circulating T and B lymphocytes that respond to the myelin antigens myelin basic protein (MBP) and proteolipid protein (PLP), thereby suggesting a role for immunoregulatory cytokines. MATERIALS AND METHOD: Blood mononuclear cells (MNC) were prepared from patients with MS, optic neuritis (ON), myasthenia gravis (MG), other inflammatory (OIND) and non-inflammatory neurological diseases (OND), and from patients with HIV infection and healthy controls. MNC expressing cytokine mRNA were detected by in situ hybridization with radiolabelled cDNA oligonucleotide probes. Numbers of cytokine mRNA expressing cells were presented per standard numbers of MNC. RESULTS: MS patients had elevated numbers of MNC in blood expressing T helper type 1 (Th1) cell related interferon-gamma (IFN-gamma), Th2 cell associated interleukin-4 (IL-4) and the endogenously produced immunosuppressant transforming growth factor-beta (TGF-beta). IFN-gamma and TGF-beta correlated with MS disability: EDSS score < 3 was associated with high numbers of TGF-beta mRNA positive cells while IFN-gamma mRNA positive cells tended to be low. The reverse was seen in patients with EDSS > or = 3. Cultures of MNC in presence and absence of antigen revealed that MBP and PLP induced strong responses in MS reflected by high levels of IFN-gamma, IL-4 and TGF-beta mRNA expressing cells. Recombinant (r) TGF-beta 1 dose-dependently suppressed MBP-induced upregulation of the proinflammatory cytokines IFN-gamma, IL-4, IL-6, tumor necrosis factor-alpha, (TNF-alpha), TNF-beta and perforin, but not of the immunosuppressive and probably advantageous IL-10. Cytokine mRNA expressing cells were enriched in the MS patients' cerebrospinal fluid, as were the cytokine mRNA positive cells detected after culture in presence of MBP and PLP, reflecting an autonomy of the immune response in this compartment. ON, in many instances representing early MS, did not differ from clinically definite MS regarding profiles of IFN-gamma, IL-4 and TGF-beta. Also patients with MG had elevated numbers of IFN-gamma, IL-4 and TGF-beta mRNA expressing blood MNC. They were further augmented upon culture of the MG patients' MNC in presence of acetylcholine receptor (AChR). An upregulation of AChR-induced TGF-beta was observed in thymectomized patients. rTGF-beta suppressed AChR-induced upregulation of proinflammatory cytokines but not IL-10. Elevated numbers of IFN-gamma, IL-4 and TGF-beta mRNA expressing blood MNC were also found in patients with OIND (aseptic meningo-encephalitis, chronic inflammatory demyelinating polyneuropathy, polymyositis, Eaton-Lambert syndrome) and in HIV-infected patients. In HIV infection, numbers of IL-4 mRNA positive cells correlated inversely with CD4+ cell counts, reflecting the involvement of IL-4 in later stages of the disease. Patients with non-inflammatory neurological diseases and healthy subjects had either no or low numbers of IFN-gamma, IL-4 and TGF-beta mRNA expressing cells when blood MNC were examined without previous culture, and after culture in presence and absence of MBP, PLP and AChR as antigens. An exception was a healthy pregnant lady who showed high levels especially of IL-4 and IL-10 mRNA expressing cells, probably reflecting pregnancy-associated upregulation of Th2 cell related cytokines. Numbers of myelin antigen- and AChR-reactive IFN-gamma and IL-4 mRNA expressing cells were also elevated, implicating upregulation of natural T cell autoimmunity in normal pregnancy. CONCLUSION: High numbers of in vivo activated and of organ-specific antigen-responsive Th1 and Th2 like cells expressing IFN-gamma and IL-4 mRNA are characteristic for MS and MG. Upregulation of TGF-beta in MS patients with little disability and in MG after thymectomy implicates that TGF-beta has desirable effects in human diseases with autoimmune background.

Adolescent↗