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Biomedical subjects

M Weller

Publications and source records attributed to M Weller.

At least 289 records · Page 16Linked to original sources
PubMed1991

[The antiphospholipid syndrome. The neurological complications and the therapeutic possibilities].

For several months a 23-year-old woman had been suffering from increasingly frequent attacks of bilateral amaurosis fugax. They affected only individual segments of a monocular visual field and finally occurred several times daily. Physical and cardiological examinations as well as echocardiography were within normal limits. Laboratory tests revealed a slight increase in erythrocyte sedimentation rate and high titres of serum antibodies against phospholipids. Fundoscopy did not show any vascular changes. Because vasculitis--possibly as an expression of systemic lupus erythematodes--was suspected, high-dosage treatment with steroids was commenced, but failed to influence the visual disorder. While steroid dosage was gradually decreased, administration of acetylsalicylic acid (for three months 100 mg daily, then three times daily 100 mg) brought about complete disappearance of the visual signs. Their cause was probably a reversible platelet aggregation induced by antiphospholipid antibodies which, because of the physiological characteristics of the terminal retinal vascular bed brought about the isolated sign of recurrent amaurosis fugax.

Adult↗
PubMed1991

Cerebrospinal fluid interleukins, immunoglobulins, and fibronectin in neuroborreliosis.

Intrathecal synthesis of IgM and IgG, oligoclonal immunoglobulin bands, and the levels of fibronectin, soluble interleukin 2 receptor, interleukin 6, and tumor necrosis factor alpha were investigated with the use of enzyme-linked immunosorbent assay in 46 paired cerebrospinal fluid and serum samples from 32 patients with meningopolyradiculoneuritis due to Borrelia burgdorferi (Lyme borreliosis stage 2). Cerebrospinal fluid and serum interleukin 6, although not specific for neuroborreliosis, were good indicators of disease activity, while the serum soluble interleukin 2 receptor level was only mildly elevated. Tumor necrosis factor alpha was never detected in cerebrospinal fluid or serum specimens, and cerebrospinal fluid IgM, IgM index, and cerebrospinal fluid IgM/cerebrospinal fluid IgG ratios were significantly higher than in all other neuroimmunologic disorders evaluated and may be valuable diagnostic indicators for neuroborreliosis. The estimation of intrathecally synthesized IgG and IgM fractions for the differential diagnosis of neuroimmunologic disorders did not add to IgG and IgM index calculations.

Antibody Formation↗
PubMed1991

An immunochemical quantitative analysis of the protein pattern in physiologic and pathologic vitreous.

Biochemical changes in the vitreous in different vitreoretinal disorders have not yet been thoroughly studied. Using enzyme-linked immunosorbent analysis (ELISA), we established mean values and 95% confidence intervals for six proteins of physiologic human vitreous: albumin (293 +/- 18 mg/l), transferrin (73.7 +/- 6.6 mg/l), immunoglobulin G (IgG), (33.5 +/- 3 mg/l), alpha 1-antitrypsin (14.1 +/- 2.9 mg/l), alpha 1-acid glycoprotein (4 +/- 0.7 mg/l), and lactoferrin (less than 50 micrograms/l). These six proteins were also determined in vitreous aspirates from patients with idiopathic proliferative vitreoretinopathy (n = 10), traumatic proliferative vitreoretinopathy (n = 10), and proliferative diabetic retinopathy (n = 15). The pattern of protein levels varied widely within each of the disorders. An analysis of absolute protein levels showed significant differences in total protein and alpha 1-antitrypsin levels between controls and pathologic vitreous samples. We observed differences in transferrin between controls and proliferative diabetic retinopathy (PDR), and differences in alpha 1-acid glycoprotein between controls and both types of proliferative vitreoretinopathy (PVR). The single disorders themselves could not be differentiated by any of the proteins. When the relative contribution of single proteins to total vitreal protein was compared, albumin was lower in all three disorders than in controls. Transferrin was lower in traumatic PVR than in controls, in PDR, or in idiopathic PVR. Our results indicate that the three vitreoretinal disorders studied are characterized by a breakdown of blood-ocular barriers.

Albumins↗
PubMed1991

Vitronectin and proliferative intraocular disorders. I. A colocalisation study of the serum spreading factor, vitronectin, and fibronectin in traction membranes from patients with proliferative vitreoretinopathy.

The presence of a scaffold for cellular spreading and proliferation is a precondition for the development of traction membranes in proliferative vitreoretinopathy (PVR). This study shows the presence of the serum spreading factor, vitronectin, in the extracellular matrix of periretinal membranes removed during vitreoretinal surgery. By means of a double label immunofluorescence protocol, a partial colocalisation of vitronectin with fibronectin at the magnification of light microscopy can be detected. Fibronectin is a high-molecular glycoprotein with multiple biological functions including the mediation of cell attachment and migration. Both proteins share a special cell recognition site which could be a target for experimental pharmacological approaches to PVR. Preliminary studies of vitreous aspirates using electrophoresis and Western blotting indicate that vitronectin may play a more important role in post-traumatic PVR as compared to PVR following rhegmatogenous retinal detachment.

Blotting, Western↗
PubMed1991

Vitronectin and proliferative intraocular disorders. II. Expression of cell surface receptors for fibronectin and vitronectin in periretinal membranes.

Several cell types participate in the formation of vitreoretinal traction membranes in proliferative intraocular disorders. The communication between these cells involves hormones, growth factors, and the interaction with extracellular matrix molecules. We have previously demonstrated a partial colocalisation of two potent mediators of cell attachment, fibronectin and vitronectin, in periretinal membranes from patients with proliferative vitreoretinopathy (PVR). We found a similar pattern of vitronectin and fibronectin deposition in proliferative diabetic retinopathy (PDR) (n = 6). Now we show the expression of the corresponding cell surface receptors, integrins, for fibronectin and vitronectin by proliferating cells in 22 periretinal membranes, including traumatic (n = 8) and idiopathic (n = 8) PVR as well as PDR membranes (n = 6). Integrins are membrane receptors for extracellular matrix macromolecules which are involved in such basic biological phenomena as embryogenesis and metastasis. Future studies on the pathogenesis of vitreoretinal proliferation will have to focus on the initiation, maintenance, and regulation of this intercellular communication network involving attachment proteins and integrins.

Diabetic Retinopathy↗
PubMed1991

Neurosarcoidosis without systemic sarcoidosis.

Neurosarcoidosis is a well-recognised complication of systemic sarcoidosis but diagnosis may be difficult if there is no clear evidence of an extracerebral manifestation of the disease. We present the case of a 42-year-old woman with clinical features characteristic of cerebral sarcoidosis including tetraparesis, diabetes insipidus, diencephalic hyperphagia, personality changes, and memory loss. Diagnosis was supported by cerebrospinal fluid (CSF) findings and magnetic resonance imaging (MRI): CSF showed mild lymphocytic pleocytosis, intrathecal production of IgG without oligoclonal bands, and a raised level of lysozyme. MRI revealed multiple contrast-enhanced granulomas at the base of the brain with partial involvement of diencephalic and mesencephalic structures and parts of the spinal cord. There was no evidence of systemic manifestation of sarcoidosis. Administration of corticosteroids led to improvement of the symptoms.

Adult↗
PubMed1991

Retinal microglia: a new cell in idiopathic proliferative vitreoretinopathy?

Despite numerous studies of the role of mononuclear phagocytes in proliferative vitreoretinopathy, the origin of these cells has remained obscure. Notably, retinal microglial cells have consistently been neglected. Applying double label immunohistology with a set of new cell markers to 37 preretinal traction membranes, we have identified a distinct population of proliferating cells presumably of microglial origin. The identification of microglia relies on positive labels for LN-1, Ricinus communis agglutinin-1, vimentin, HLA-DR, and nucleoside diphosphatase, and negative labels for Leu-M1, Leu-M3, EBM-11, von Willebrand factor, CD22, cytokeratin, and glial fibrillary acidic protein. Microglia are much more prevalent in idiopathic than in traumatic proliferative vitreoretinopathy and insignificant in proliferative diabetic retinopathy. HLA-DR expression was not restricted to pigment epithelium as previously reported but also observed in microglia, macrophages, endothelial and glial cells. The detection of retinal microglial cell proliferation suggests a pathogenetic role of these cells and questions current concepts of the cellular biology of proliferative vitreoretinopathy.

Antigens↗
PubMed1991

Comparative analysis of cytokine patterns in immunological, infectious, and oncological neurological disorders.

Interleukins (IL) 1, 2, 4, 6 and soluble IL-2 receptor (sIL-2R), interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha) were measured in CSF and serum from patients with relapsing-remitting and chronic multiple sclerosis, Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy, HIV infection, bacterial meningitis, viral encephalitis, meningeal carcinomatosis, hematologic meningeal malignancies, and disseminated melanoma. Our findings suggest that monitoring of disease activity in neuroimmunologic disorders by means of IL-1 beta, IL-2, sIL-2R, or IL-4 determination will not prove useful. IL-6, on the other hand, indicates relapse in multiple sclerosis and active disease in Guillain-Barré syndrome and meningeal carcinomatosis. High CSF TNF-alpha in metastatic melanoma and frequent detection in CSF of the multifunctional B-cell growth factor, IL-6 (27/30) and oligoclonal immunoglobulin bands (33%) in meningeal carcinomatosis confirm an intrathecal immune response in disseminated leptomeningeal neoplasia which might be amenable to therapeutic immunomodulation.

Cytokines↗
PubMed1991

Pulmonary blastoma: a rare childhood malignancy.

Pulmonary blastoma is a rare primary malignancy of the lung, with few cases reported in children. The tumor consists of mesenchymal and epithelial components resembling the fetal lung. Seven children (aged 18 months to 5 years) with pulmonary blastoma were studied. The pulmonary radiographic patterns seen were a large, space-occupying solid mass with opacification of the hemithorax and preexisting cystic disease with a small solid tumor component. Computed tomographic images showed a low-attenuation mass with whorls of high-attenuation solid tissue. Four of the seven patients died within 2 years despite surgery and therapy; of the three surviving patients, one has recurrent disease.

Child, Preschool↗
PubMed1991

Differences in the medical and legal viewpoint illustrated by R v Hardie [1984].

The case of R. v Hardie [1984] creates an important precedent and is cited in the current edition of Archbold (1989). It is argued that the pharmacological issues discussed therein contain errors that seem to go to the heart of the judgment, which illustrates the differences between the legal and scientific viewpoint.

Attitude to Health↗
PubMed1991

[Thrombospondin and its importance in proliferative retinal diseases].

Thrombospondin (TSP), a platelet-derived protein of the integrin-binding family with adhesive and mitogenic properties was localized in surgically obtained epiretinal traction membranes from patients with traumatic (7/8) and idiopathic (8/8) proliferative vitreoretinopathy (PVR) and proliferative diabetic retinopathy (PDR) (6/8). Using double-label immunofluorescence techniques, we demonstrated co-localization of TSP with the endothelial cell marker, von Willebrand factor, in PDR; however, only a minority of labeled macrophages showed simultaneous staining for TSP. Therefore, macrophages are probably not a major source of TSP in PVR. We demonstrated co-distribution of blood coagulation factor XIII and two of its cross-linking substrates, fibronectin and TSP, in epiretinal membranes, as well as the detection of plasmin and presumably plasmin-induced TSP breakdown products in physiologic and pathologic vitreous. These results suggest that the coagulation system has a functional role in proliferative retinal disorders and imply that the application of inhibitors of the coagulation cascade like heparin may be a potential therapeutic approach.

Antibodies, Monoclonal↗
PubMed1991

[Analysis of the protein pattern in physiologic and pathologic vitreous bodies by electrophoresis and immunologic identification].

The protein composition of normal and pathological human vitreous was analyzed using gradient SDS-PAGE and western blot. By electroblotting and immunodetection, the presence of ten proteins was proven in the normal vitreous. The major proteins included: albumin, transferrin, alpha-1-antitrypsin, and immunoglobulin G. For the detection of a distinct protein in the vitreous, western blot analysis seems to be an appropriate method. Using densitometric analysis of silver-stained gels, we compared the protein pattern of post-mortem vitreous, surgically obtained samples (from proliferative vitreous-retinopathy, proliferative diabetic retinopathy, and macular pucker patients), and serum. The protein composition of the pathological intraocular fluid was uniform, but different from that of normal vitreous and serum. These results suggest that a breakdown of the blood-retina barrier is the main reason for the increase of soluble proteins in the vitreous cavity under pathological conditions. The methods described allow detailed analysis of the vitreous protein pattern in intraocular proliferative disorders with a small sample volume (10 microliters).

Blood-Retinal Barrier↗
PubMed1991

The significance of complement in proliferative vitreoretinopathy.

Complement is the principal effector arm of antibody-mediated allergic response and plays a central role in the pathogenesis of many immunologic disorders. The possible pathophysiologic importance of complement was examined in the development of proliferative vitreoretinopathy (PVR). Vitreous aspirates from patients with idiopathic PVR (n = 21) and traumatic PVR (n = 15) were examined for total vitreal protein (TVP) and complement components C3, C3d, C4, and C1q-fixed immunoglobulins using enzyme-linked immunosorbent assay (ELISA), sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and western blotting. The TVP, C3 components, and factor C4 were elevated significantly in diseased vitreous. The C3-TVP and C4-TVP ratios showed no difference between traumatic and idiopathic PVR. A C4 index to estimate the rate of intraocular C4 synthesis had a mean value of 3.2 (n = 15). The increased relative amount of C3d reflected complement activation in diseased vitreous. The negative values in normal human serum and plasma and in patient plasma samples (n = 15) indicated a local reaction in the eye. The authors found C1q-fixed immunoglobulin G; this may be the cause of complement activation by the classic pathway. These findings support the opinion that the cause of PVR may be based partly on an autoimmune reaction against ocular structures.

Autoimmune Diseases↗
PubMed1990

Proliferative vitreoretinopathy--is it anything more than wound healing at the wrong place?

Proliferative vitreoretinopathy (PVR) is a reactive process of the ocular tissue after perforating trauma, retinal detachment, and surgical manipulations. Although several studies, most of them experimental, have focused on the detection of specific etiologic factors in the development of PVR, there is compelling evidence that PVR is nothing more than a physiologic tissue repair process with undesirable consequences for the retina. Important features of PVR involving the role of platelets, mononuclear phagocytes, and fibroblasts parallel the chain of events observed in tissue repair elsewhere in the body. Numerous experimental models for PVR, originally designed to find specific stimuli for the generation of intraocular traction membrane formation, have shown that the process of PVR is the common pathway of the eye's reaction to vitreoretinal trauma of any kind. Accordingly, vitreoretinal surgeons could learn a lot from the work of other disciplines, e.g. surgery and dermatology, on wound healing, and the factors known to modify wound healing elsewhere in the body should be taken into consideration. The well-established impairment of tissue repair processes caused by medical treatment with corticosteroids and cytotoxic agents suggests a combined medical approach to PVR as an adjunct to surgical treatment, using refined methods of application and dosage. Steroids and cytotoxic drugs will influence the course of PVR by suppressing macrophage recruitment and the initial inflammatory reaction as well as the proliferative phase of wound healing with traction retinal detachment, respectively.

Blood Platelets↗
PubMed1990

Immunoglobulin G, complement factor C3 and lymphocytes in proliferative intraocular disorders.

This study examines a possible immunological contribution to the development of proliferative intraocular disorders (PID) with traction retinal detachment. We analysed 24 periretinal membranes and 35 vitreous aspirates from patients with idiopathic proliferative vitreoretinopathy (PVR), traumatic PVR, and proliferative diabetic retinopathy (PDR). Lymphocytes and complement factor C3 deposits could not be detected in any of the membrane specimens. IgG was present in all but one of the PVR membranes but in less than half of the PDR specimens and there to a lesser extent. The IgG immunoreactivity was not collocalized with macrophages but instead located to the extracellular matrix. The intravitreal levels of IgG (ELISA) and protein were elevated in PID but the range of these biochemical changes was so wide that there were no significant differences of the IgG levels between the single types of PID. Using electrophoresis and Western blotting, C3 was detected in normal and pathologic vitreous but smaller C3 fragments indicative of C3 breakdown were only found in PID.

Blotting, Western↗
PubMed1990

Opercular syndrome without opercular lesions: Foix-Chavany-Marie syndrome in progressive supranuclear motor system degeneration.

A patient is described with slowly progressive supranuclear motor system degeneration (primary lateral sclerosis) characterized by pure bulbar spasticity for six years until a spastic tetraparesis developed. Clinically and electrophysiologically there was and still is no evidence of lower motor neuron involvement. Recently the patient presented with a syndrome of complete inability to move face and tongue voluntarily with preservation of the ability to move them "automatically", e.g. within gestures: automatic-voluntary motor dissociation. Loss of voluntary innervation of the facio-pharyngo-glossomasticatory muscles with preservation of involuntary innervation are the features of the Foix-Chavany-Marie syndrome, which to date has most often been described in association with bilateral vascular lesions of the opercula or their cortigofugal projections.

Amyotrophic Lateral Sclerosis↗