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P Esser

Publications and source records attributed to P Esser.

64 records · Page 4Linked to original sources
PubMed1990

[Vitronectin and fibronectin receptors in proliferative retinal diseases].

Integrins are membrane receptors which, together with their corresponding adhesion proteins, constitute a versatile recognition system and provide cells with information for position, anchorage, differentiation, migration, and growth. Vitronectin and fibronectin are two potent mediators of cell adhesion which, together with their receptors, represent a highly sophisticated system of communication in proliferative intraocular disorders. Using an immunofluorescence technique, we demonstrate a similar pattern of partial colocalization of vitronectin and fibronectin in proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR). Furthermore, we show the expression of the corresponding cell surface receptors for vitronectin and fibronectin in membranes from patients with traumatic PVR (n = 8), idiopathic PVR (n = 8), and PDR (n = 6). At this time, it seems that further studies on integrins and their significance in proliferative retinal disorders are necessary before pharmacological approaches based on receptor antagonism can prove themselves to be possible and clinically applicable.

Fibronectins↗
PubMed1989

[Psychological management of heart patients and their relatives in the pre- and postoperative phases: experiences from a 2 year model trial].

The psychological and neurological disorders as well as psychosocial problems experienced by cardiac patients and their relatives while waiting for coronary artery bypass surgery are outlined, as well as their intrapsychic situation following the operation. With a view to providing long-term psychological support and care of cardiac bypass patients and their relatives, a care model has been developed which emphasizes the following: (1) initial contact and individual counselling immediately following establishment of the indication for surgery (2) client-centered groups to prepare for the operation, involving both the patients and their partners (3) client-centered (therapy)/relaxation groups for postoperative patients. This model trial is described, covering its development, structure, and contents in some detail. An evaluation is given, as is an explanatory case presentation. The results obtained from 48 cardiac bypass patients in a follow-up study of their views concerning the psychological care provided, are presented in a summary account. Concluding, the authors outline future emphases for practical work and research.

Adaptation, Psychological↗
PubMed1986

Progression of coronary atherosclerotic disease assessed by cinevideodensitometry: relation to clinical risk factors.

Progression of coronary artery stenosis was measured using a quantitative, computer-assisted cinevideodensitometric method in 144 arterial segments in 44 subjects undergoing coronary arteriography on two separate occasions at least 6 months apart. Projected coronary arteriograms were digitized into 512 X 512 pixel mode and percent stenosis was calculated by comparing background-corrected videodensitometric values over stenotic and normal segments. Subjects underwent repeat coronary arteriography because of worsening symptoms of angina or heart failure; subjects with renal failure, coronary artery bypass grafts or cardiac transplant were excluded. Clinical variables determined at the time of the first arteriogram included age, sex, serum cholesterol, systolic blood pressure and presence or absence of cigarette smoking, diabetes mellitus and left ventricular hypertrophy. The mean interval between arteriograms was 29.3 months. Overall progression of coronary stenosis was observed in 40 of the 44 subjects; the mean progression at 24 months was 39% (90% confidence interval, 33 to 45%) and at 36 months was 48% (40 to 56%). The degree of overall progression was related to the length of time between arteriograms (F = 5.81, p less than 0.05) and to serum cholesterol level (F = 4.37, p less than 0.05). These data indicate that using an accurate, quantitative method, it is possible to measure progression of coronary artery atherosclerosis within 2 to 3 years of the initial arteriogram. Serum cholesterol appears to be an important determinant of disease progression.

Angiography↗
PubMed1983

A model for prediction of resynchronization after time-zone flights.

Utilizing experimental data from three flight studies, a concept was developed which allows appraising average resynchronization for any day after arrival in a new time-zone. The course of adaptation is nonlinear and can be mathematically represented by an exponential function. The model predicts higher initial resynchronization rates when more time zones are crossed, but total time for complete reentrainment is essentially the same and, thus is independent of the number of time-zones. The equation derived from experimental data is converted into an e-function and the resulting time constants are presented as they evolved for different functions and flight directions.

Aerospace Medicine↗
PubMed1981

Partial purification and properties of neuraminidase from Bifidobacterium lactentis.

Bifidobacterium lactentis 659 a gram-positive, nonsporeforming anaerobic bacterium originally isolated from the feces of breast-fed infants produces neuraminidase after enzyme induction with 2mM N-acetylmannosamine added to the culture medium. Bacteria were transferred and grown in a medium containing casein hydrolysate, lactose, sodium acetate, amino acids, vitamins, salts and 2% human milk for 48 h at 37 degrees C under N2/CO2 atmosphere. Two subcultures derived from the original strain B. lactentis 659 were investigated separately because of different growth characteristics. However, their taxonomic identity was not doubtful. Neuraminidase was liberated from the bacterial sediments by ultrasonic treatment in 0.15M NaCl and was isolated by 60% ammonium sulfate precipitation, dialysis, concentration, and column chromatography on Sepharose CL-6B and Sephadex G-100. The enzyme exhibits a molecular weight of 38000 and a pH optimum in the range of pH 5--6 in barbital/acetate buffers. Starch gel electrophoresis and neuraminidase-specific staining with NeuAc alpha 2 leads to (3-methoxyphenyl) glycoside revealed two major and three minor enzyme bands. Michaelis constants (Km) were determined to be 7.1 mM for the (alpha 2 leads to 3) linkage of II3NeuAc-Lac, 7.5mM for the (alpha 2 leads to 6) linkage of II6Neu-Ac-Lac and 15mM for the (alpha 2 leads to 8) linkage in II3(leads from 2NeuAc8)2-Lac. Among the different groups of naturally occurring NeuAc-containing substrates, i.e. glycoproteins, gangliosides and oligosaccharides, B. lactentis neuraminidase cleaves oligosaccharides preferentially without remarkable differences between (alpha 2 leads to 3) and (alpha 2 leads to 6) linkages. Globular glycoproteins and mucins are poor substrates and gangliosides are practically not affected. In contrast, enzyme activity towards synthetic NeuAc glycosides is very high. The enzyme is activated by 50% with 50mM Ca2 and inhibited by 20mM EDTA accordingly. In general, B. lactentis neuraminidase shows a substrate specificity pattern similar to those found in other non-pathogenic and non-invasive representatives of the human bacterial flora. The potential biological role of intestinal Bifidobacteria will be discussed.

Actinomycetaceae↗
PubMedDate not supplied

Vitrectomy for macular detachment associated with optic nerve pits.

OBJECTIVE: To describe the pathogenic mechanism for a central retinal detachment in eyes with a pit of the optic disc. DESIGN: Three patients with macular detachment associated with optic nerve head pits were prospectively controlled following pars plana vitrectomy. METHODS: Three cases of macular detachment associated with congenital optic nerve pit were treated with pars plana vitrectomy and air-fluid exchange and sulphur hexafloride (SF6) gas injection. During vitrectomy posterior hyaloid removal caused visible traction on the elevated retina, when the hyaloid detached. Removing the posterior hyaloid resulted in reattachment of the macular and an increase in the visual acuity without laser treatment. CONCLUSION: We recommend the removal of the posterior hyaloid face during pars plana vitrectomy in patients with central macular detachment associated with a pit of the optic disc.

Adolescent↗
PubMedDate not supplied

Basic fibroblast growth factor mRNA, bFGF peptide and FGF receptor in epiretinal membranes of intraocular proliferative disorders (PVR and PDR).

Basic fibroblast growth factor (bFGF) has been shown to be involved in epiretinal membrane formation in proliferative vitreoretinal disorders. However, up to now, little knowledge exists; as to the actual cellular source of this potent mitogen. We examined 20 epiretinal membranes from patients with proliferative diabetic retinopathy (PDR) (n = 12) and proliferative vitreoretinopathy (PVR) (n = 8) for the presence of bFGF peptide, fibroblast growth factor receptor-1 (FGFR-1) and bFGF messenger ribonucleic acid (mRNA). Using a specific antibody, we detected bFGF peptide in most (8/10) examined PDR membranes and in all (8/8) PVR membranes. Moreover, we found positive staining for the corresponding receptor. Local production of bFGF in epiretinal membranes was confirmed by nonisotopic in situ hybridisation for bFGF mRNA in some (4/7) examined PDR membranes and some (3/4) examined PVR membranes. All membranes which contained bFGF mRNA were also positive for bFGF peptide. In conclusion, bFGF is produced and stored in epiretinal membranes. Together with the corresponding receptor, bFGF may play a role in the auto- and paracrine control of the proliferative processes at the vitreoretinal interface.

Adult↗
PubMedDate not supplied

Mononuclear phagocytes in proliferative vitreoretinopathy (PVR). A specific role of microglial cells in non-traumatic disease?

Mononuclear phagocytes have been a focus of attention in the cellular biology of proliferative vitreoretinopathy (PVR) for more than ten years. The pattern of phagocyte participation in periretinal traction membrane formation in PVR depends on the etiology, i.e. trauma, rhegmatogenous retinal detachment, previous therapy, i.e. multiple surgical interventions, and the clinical stage of the disease. We have recently identified microglial cells as a distinct cellular population, in membranes from patients with non-traumatic PVR. Current evidence of mononuclear phagocyte function in PVR suggests a role for resident phagocytes of the vitreous and retina in PVR subsequent to rhegmatogenous detachment, and a role for blood-derived monocytes in post-traumatic PVR. The cellular biology of PVR may be much more heterogeneous than previously assumed.

Diabetic Retinopathy↗
PubMedDate not supplied

Thrombospondin: a new attachment protein in preretinal traction membranes.

Thrombospondin (TSP), an adhesive integrin-binding protein of plasma and platelets, was detected in preretinal traction membranes from patients with idiopathic (8/8) and traumatic (7/8) proliferative vitreoretinopathy (PVR) and proliferative diabetic retinopathy (PDR) (6/8). TSP immunoreactivity was compared to the pattern of von Willebrand factor, plasma transglutaminase (blood coagulation factor XIII), fibronectin, and mononuclear phagocytes, using double-label immunofluorescence microscopy. TSP was partially colocalised with the endothelial cell marker, von Willebrand factor, in PDR. The codistribution of catalytic factor XIII and two cross-linking substrates, fibronectin and TSP, suggests a functional role of the enzyme in the extracellular matrix build-up in PVR and PDR. No significant TSP synthesis by mononuclear phagocytes was observed. Western blotting indicated a plasmin-mediated intravitreal breakdown of presumably plasmatic TSP in PVR and PDR.

Antibodies, Monoclonal↗