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Biomedical subjects

C Mittermayer

Publications and source records attributed to C Mittermayer.

At least 91 records · Page 5Linked to original sources
PubMed1990

[Immunohistochemical studies of the human lens capsule].

In this study we made an attempt to localize components of the human lens capsule using immunohistochemical methods. Type IV collagen could be shown in all parts of the capsule in equal distribution. It could be found over the whole thickness of the lens capsule. By comparison, laminin could be detected only at the inner layer of the capsule. There was no difference concerning the contribution of these components between the anterior and the posterior capsule. No specific staining of collagen types I and III or of fibronectin could be found.

Collagen↗
PubMed1989

Topography of the inferior rectal artery: a possible cause of chronic, primary anal fissure.

The authors believed that it might be possible to explain the local frequency of the anal fissure at the posterior commissure by an anatomic relationship, and examined the blood supply of the anus. The inferior rectal artery is demonstrated by postmortem angiography and by manual preparations (N = 41) and histologic study after angiography of the vessels (N = 10). The blood supply at the different sites of the anal canal are demonstrated by a morphometric study (N = 20). The inferior rectal artery presents two variants in the postmortem angiographies, type 1 (85.4 percent) and type 2 (14.6 percent). In type 1, the posterior commissure is less perfused than the other sections of the anal canal. In addition, the blood supply may be more compromised by contusion of the vessels passing vertically through the muscle fibers of the sphincter ani internus muscle during increased sphincter tone. The role of topography in the pathogenesis of the primary anal fissure is illustrated in a model.

Anal Canal↗
PubMed1989

DNA grading of oral squamous carcinomas. A preliminary report.

The prognostic validity of the DNA-malignancy-grade (DNA-MG), ranging on a continuous scale from 0.00 to 3.00 was tested in a preliminary study on 7 patients with oral squamous cell carcinomas. Monolayer smears were prepared after a cell separation procedure from paraffin-embedded surgical tumor specimens. Feulgen staining was performed automatically in a modified Shandon staining machine. A TV image analysis system with an automatic microscope (TAS plus, Leitz, FRG) was used for DNA measurements. The DNA-MG revealed a strong correlation with the patients prognosis. 3 patients who died after having a tumor relapse (mean survival = 10 months) had DNA grades greater than 1.40, whereas patients who survived without having a tumor relapse (mean survival = 53 months) revealed DNA grades below 1.00. Additionally, the DNA-malignancy-grade was closely correlated with the histopathologic malignancy grades.

Adult↗
PubMed1989

Proliferation kinetics-study of the growth of keratocysts. Morpho-functional explanation for recurrences.

The mode of growth of the odontogenic keratocyst is of decisive importance in the strategy and radicality of its surgical removal. The high rate of recurrence reported in the literature is striking. Staining with haematoxylin-eosin for histological examination provides only limited information on growth. Serial sections of a keratocyst obtained by fractionated curettage were prepared and the proliferation patterns of epithelium and connective tissue were studied by means of autoradiography and DNA cytophotometry and compared with those of an odontogenic reference cyst of the radicular type. The epithelium of the keratocyst examined clearly showed a higher rate of proliferation than that of the radicular cyst. The connective tissue was also growing very actively with a high rate of proliferation and this growth behaviour is at least partly responsible for the invasive and destructive growth of the keratocyst. In contrast to the radicular cyst, proliferation of the epithelium of the keratocyst is multicentric being simultaneous within the growth centres. As a result the epithelium "buds" with formation of satellite cysts in the alveolar bone and peripheral epithelial islands located in the connective tissue. A case is reported of a keratocyst treated by radical curettage with subsequent freshening of adjacent bone with a bur. Our morphological findings are an important contribution to the present discussion of the various methods of treating keratocysts.

Autoradiography↗
PubMed1989

[The filter effectiveness of common 15-micron filters (DIN 58362). II: Scanning electron microscopy and roentgen analysis].

When i.v. solutions are used, millions of foreign particles are washed into the organism. Our town studies could recently show that these particles may interact with the organism and thus cause injury. A new method is introduced here (energy dispersive X-ray analysis in scanning electron microscopy, SEM, Jeol 35 CF/EDX, EEDS II Ortec), with which the element combination of foreign particles can be analyzed qualitatively and quantitatively. As a first step an analysis of the particulate matter in filtrates of infusion solutions was carried out in the same way, materials used in infusion therapy (e.g. infusion sets, cannulas, etc.) were analyzed. The results show that most of the particulate matter consists of glass from ampoules, plastic materials from infusion sets and rubber from the rubber stoppers of infusion bottles.

Electron Probe Microanalysis↗
PubMed1989

[Particulate contamination of infusion solutions and drug additives within the scope of long-term intensive therapy. 1. Energy dispersion electron images in the scanning electron microscope-REM/EDX].

During use of i.v. solutions, particulate matter may be introduced into the patient. X-ray analyses have shown that the particulate matter consists mainly of glass from ampules, rubber from stoppers of infusion bottles, and plastic from infusion sets. A new method is introduced: scanning electron microscopy-SEM- in combination with energy-dispersive X-ray analysis-EDX. using this technique all foreign particles larger than 0.8 microns can be detected and analyzed in any tissue. Especially in critically ill patients, particularly matter is deposited in the microcirculation of the lung. The particles cause a variety of pathologic changes (formation of thrombi, thromboembolization of the microcirculation, destruction of the vascular endothelium, formation of granulomas and foreign body giant cells). The adult respiratory distress syndrome could be produced or respiratory insufficiency might be aggravated following circulatory shock. It is therefore recommended that terminal in-line filters with small pore sizes be used for all i.v. solutions.

Adult↗
PubMed1989

Interaction between endothelial cells and basement membrane components. In vitro studies on endothelial cell adhesion to collagen types I, III, IV and high molecular weight fragments of IV.

Understanding the mechanisms involved in maintaining the integrity of the vascular endothelium is fundamental to studies on atherosclerosis, thrombosis, inflammation and tumor invasion. One of the essential aspects is the relationship between the endothelial cell (EC) layer and the underlying components of the basement membrane (BM). The importance of the biological role of the individual components of the BM in the promotion of EC adhesion is investigated. In this study suspensions of bovine corneal ECs (BCECs; 5 x 10(4)/ml) were used to investigate the adhesion of EC to collagen type IV and a mixture of fragments of the tetrameric molecule (IV-F, consisting of 75, 120 and 140 kD fragments), as well as collagen types I and III, coated at a 10-micrograms/ml concentration onto glass coverslips in vitro. Adhesion was quantified after 2 h of interaction by direct counting in the light microscope following fixation of the adherent cells. Collagens type IV and IV-F markedly promoted BCEC adhesion both in the presence or absence of 10 or 50% fetal calf serum, indicating that the integrity of the tetrameric molecule is not required for EC adhesion to collagen type IV, but can be replaced by high molecular weight fragments. Collagens type I and III increased EC adhesion in the absence of serum, although not in the presence of serum. Indirect evidence for a possible role of fibronectin in EC adhesion to type-IV collagen is given by the ability of the tetrapeptide (Arg-Gly-Asp-Ser (10 micrograms) to temporarily block (15-30 min) the adhesion-promoting effect of type-IV collagen. The nature of the adhesion sequences on the fragments of type-IV collagen remains to be elucidated.

Amino Acid Sequence↗
PubMed1989

[Particulate contamination of infusion solutions and drug additives in the framework of long-term intensive therapy. 2. An animal model].

When IV solutions are used, particulate matter may be introduced into the patient. Using X-ray studies we could demonstrate particulate matter consisting mainly of glass from ampules, rubber from rubber stoppers of infusion bottles, and plastic material from IV sets. With a recently introduced method of back-scatter pictures in scanning electron microscopy combined with X-ray studies--Jeol 35 CF/EEDS II Ortec (REM EDX)--we analyzed this phenomenon using an animal model (rabbit). It appears that particulate matter is deposited in the interstitial lung tissue and especially the pulmonary microcirculation. Pathogenetic effects could also be demonstrated (formation of thrombi, etc.).

Animals↗
PubMed1989

[Role of the endothelium in adult respiratory distress syndrome (ARDS): the present and future].

Various morphological studies indicate that the microcirculation plays a vital role in the development of ARDS. The significance of the structural and functional integrity of the endothelium for normal pulmonary function is supported by cell biological data. Biochemical studies in bronchoalveolar lavage and blood from ARDS-patients, coupled with studies in animals and endothelial cell cultures support the role of a variety of mediators such as complement factors, products of the coagulation cascade and fibrinolytic system, enzymes, endotoxins and metabolites of arachidonic acid. Of particular importance is the interaction between neutrophilic granulocytes and the endothelium, although the individual components of this interaction and the relationship between cellular and humoral factors remain unclear. Furthermore, the literature shows that it is still uncertain, how the data obtained from studies in vivo and in vitro can be applied to ARDS in humans. Future research in this field must come to terms with the cell biology and pathobiology of the pulmonary endothelium, a hitherto neglected aspect. In addition, studies are essential to investigate possible additive or synergistic effects of mediators on inflammatory and endothelial cells. Finally, the role of more recently discovered inflammatory mediators and modulators in the pathogenesis of ARDS requires clarification.

Animals↗
PubMed1989

[Filtering effectiveness of conventional 15 m micron filters (DIN 58362) and newly developed 15 m micron and 5 m micron filters. I: Particle count].

When i.v. solutions are used, a considerable amount of particulate matter is washed into the patient. This particulate matter consists mainly of glass from ampoules, plastic materials from infusion sets, rubber from the rubber stoppers of infusion bottles and various materials, partly derived from the manufacturing process of the solutions. A new method of particle counting is introduced here (modified thrombocyte counter, Becton Dickinson), whereby particulate matter (less than 2 microns, greater 0.8 microns) could be counted for the first time. Using this counting method, the efficiency of the standard filtration (DIN 58362) was tested. Also tested were 2 new final filtration systems (with 15 microns and 5 microns pore-size). All 3 filtration methods were shown to be ineffective; especially small particles (less than 2 microns) cannot be eliminated by these filtration methods.

Drug Contamination↗
PubMed1988

Hydrodynamic investigation of mechanical bileaflet valves.

For hydrodynamic comparison, 11 mechanical bileaflet valves have been perfused in a mock circulation system under pulsatile flow conditions. Six St. Jude Medical valves with different sizes from No. 21 to No. 31 and five Duromedics prostheses with corresponding sizes from No. 21 to No. 29 have been investigated. Flow, pressure, and orifice area were measured, while cardiac output was varied between 2 and 6 L/min. Insufficiency (I), maximal orifice area (Amax), mean orifice area (A), discharge coefficient (CD), performance index (PI), and efficiency index (EI) were determined. The St. Jude Medical valves show higher values of orifice area when compared with the Duromedics valves. For smaller valve sizes up to No. 25, the values of the orifice area are similar. The Duromedics valves show much lower values of insufficiency; thus, for small valve sizes, the Duromedics prosthesis seems to be superior. For larger valve sizes (No. 27, No. 29, and No. 31), a decision has to be made whether higher insufficiency and higher orifice area of the St. Jude Medical valve or lower insufficiency with lower orifice area is more acceptable.

Heart Valve Prosthesis↗
PubMed1988

Clinical experience with expanded polytetrafluoroethylene Gore-Tex surgical membrane for pericardial closure: a study of 110 cases.

Complete closure of the pericardium after cardiac operations has the advantage of avoiding injury of the heart and great vessels during reoperation. Between 1985 and 1987, the pericardium was closed with Gore-Tex Surgical Membrane (SM) in a selected series of 110 patients 1 month to 76 years of age. Fifty-three patients had congenital heart lesions and 57 patients had acquired heart disease. Overall hospital mortality was 3/110 cases. In no instance was there a relationship between occurrence of death and pericardial closure with SM. There was one episode of cardiac tamponade on the seventh postoperative day. One patient developed fever and leukocytosis due to a mediastinal hematoma. During a mean follow-up of 15 months, four patients had to be reoperated upon three, four, eight weeks, and eight months after primary operation. The anterior wall of the heart had no adhesion with the SM and the other parts of pericardium could be dissected easily. Scanning electron microscopic examination of the explanted SM patches showed neither cellular ingrowth nor immunocompetent cellular elements. The Gore-Tex Surgical Membrane has the advantages of easy availability and lack of reaction between its surface and the epicardium and pericardium. We believe its routine use should be encouraged in patients with high probability of reoperation after repair of complex cardiac anomalies, implantation of bioprostheses, coronary revascularization for one- or two-vessel disease, and repair of degenerative disease of the ascending aorta.

Adolescent↗