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Biomedical subjects

C Stamm

Publications and source records attributed to C Stamm.

16 recordsLinked to original sources
PubMed1999

Coronary artery bypass procedures in septuagenarians are justified. Short and long-term results.

BACKGROUND: Elective coronary artery bypass surgery can be performed with low operative mortality. There is a controversial discussion whether short-term and long-term results of CABG justify this procedure in elderly patients. METHODS: To add to this discussion, we evaluated retrospectively, the clinical profile, operative technique, short- and long-term results of 1127 patients over 70 years of age who underwent myocardial revascularization between January 1985 and December 1996. RESULTS: Mean age of the cohort was 73.9 years and it rose continuously. In 1996, septuagenarians represented 21.5% of our coronary patients, in comparison to 6.4% in 1985. Analysis of risk factors showed an increasing prevalence of renal failure, obesity, hyperuricemia and a history of smoking. Preoperatively, 87% of our patients were in NYHA-class III or IV, and thus operated to relieve severe symptoms. The percentage of emergent operations decreased over the observed period by 10.3%. The internal mammary artery was used with rising frequency (44.8% in 1985-1992 vs 61.5% in 1993-1996). The number of simultaneous valve replacements increased, too. Postoperatively, we noted a rising incidence of respiratory failure (17.1%) and neurological disorders (13.7%). On the other hand, the need for intra-aortic balloon pumping and hemofiltration declined by 6.6% and 2.9%, respectively. Perioperative mortality (< or =24 hrs) was 3.65%, hospital mortality (< or =30 days) was 9.64%. The actuarial survival (standard error) at 1 year was 82% (+/-4.3%), and 65.7% (+/-3.8%) at 5 years. CONCLUSIONS: Our data suggest that coronary artery bypass grafting can be performed in septuagenarians at an acceptable risk. Since the large majority of patients improve symptomatically, surgery is a recommendable option for a growing number of elderly patients suffering from severe angina.

Aged↗
PubMed1998

Two-dimensional magnetic particles

Single two-dimensional (2D) atomically thick magnetic particles of cobalt and iron with variable size and shape were fabricated by combining a mask technique with standard molecular beam epitaxy. Reduction of the lateral size of in-plane magnetized 2D cobalt films down to about 100 nanometers did not essentially modify their magnetic properties; although the separation of boundaries decreased greatly, neither domain penetrated the particle, nor was any sizable shape anisotropy observed. The mutual interaction of 2D cobalt particles was negligible, and the magnetic state of a single particle could be switched without modifying the state of the neighbors. Perpendicularly magnetized iron particles did not exhibit such responses. These results suggest that only a few atoms forming a 2D in-plane magnetized dot may provide a stable elementary bit for nanorecording.

Journal Article↗
PubMed1998

Clinical anatomy of the normal pulmonary root compared with that in isolated pulmonary valvular stenosis.

OBJECTIVES: This study aimed to clarify the clinical anatomy of the pulmonary root. BACKGROUND: Many descriptions of valvular anatomy have focused on the annulus, leading to varied interpretations of abnormal valves. METHODS: Twenty-two heart specimens with isolated pulmonary valvular stenosis were examined to analyze the gross structure of the pulmonary root. For comparison, we examined a normal series of a similar age range together with nine adult hearts. Serial histologic sections were prepared from five specimens. RESULTS: The normal pulmonary valve is enclosed in a proximal sleeve of free-standing right ventricular infundibulum supporting the fibroelastic walls of the pulmonary sinuses at the anatomic ventriculoarterial junction. The valvular leaflets are attached in semilunar fashion across this junction, delimiting the extent of the valvular sinuses. The stenotic valves were separated into dome-shaped valves, dysplastic valves and a third group of less typical cases. In the dome-shaped valves, which had a relatively circular origin of their leaflets, three raphes were tethered to the arterial wall at the sinutubular junction, producing a waistlike narrowing. The leaflets of the dysplastic valves were attached in a relatively normal semilunar fashion, but stenosis was caused by thickening of the leaflets at their free edges. Serial histologic sections through normal and abnormal valves failed to demonstrate any well defined fibrous "annulus" that could be of clinical relevance. CONCLUSIONS: Unlike the normal and the dysplastic valves, the dome-shaped valves have circular rather than semilunar lines of attachment of the valvular leaflets. Liberation of the fused zones of apposition of the leaflets within the dome is unlikely to restore such abnormal valves to normal structure, even if this procedure relieves the stenosis.

Cadaver↗
PubMed1998

Anterior ischemic optic neuropathy: a complication after extracorporal circulation.

INTRODUCTION: Anterior ischemic optic neuropathy (AION) describes a defect of the optic nerve leading to irreversible loss of vision in most cases. Pathophysiology of this disease is manifold and has been discussed as a posthemorrhagic complication as well as a neurological complication after operations with cardiopulmonary bypass. METHODS: On the basis of two cases, the clinical picture is described in relation to the available literature. Preoperative risk factors, operative data, cardiopulmonary-bypass, postoperative complications and clinical symptoms are discussed together with ophthalmologic findings in order to elucidate the pathophysiology of this process. RESULTS: There is no reliable and effective treatment of anterior ischemic optic neuropathy. Neither corticosteroids, osmotic diuretics, hemodilution nor surgical decompression of the optic nerve have proved successful. Hence, measures to avoid ischemic optic neuropathy have priority. The following risk factors were determined: History of glaucoma or other ophthalmological problems, prolonged cardiopulmonary bypass-time and myocardial ischemia, general oedema during cardiopulmonary bypass, excessive hemodilution with low hemoglobin and hematocrit, hypo- or hypertension, systemic hypothermia, need for vasoactive medication. CONCLUSIONS: Influenced by a variety of factors, pathophysiological microvascular changes provoke anterior ischemic neuropathy with sudden painless loss of vision, irreversible in most cases. Since therapeutic trials have failed, prevention of possible causes is the only way to avoid this rare but severe complication of cardiac surgery.

Adrenal Cortex Hormones↗
PubMed1997

The aortic root in supravalvular aortic stenosis: the potential surgical relevance of morphologic findings.

OBJECTIVE: We aimed to elucidate the structural basis of supravalvular aortic stenosis in the context of its surgical repair. METHODS: We examined retrospectively the angiograms and echocardiograms of 37 patients and compared them with those of control groups. Additionally, we studied 8 pathologic specimens. RESULTS: Partial adhesion of the leaflets to the stenosing ridge was observed in 54% of the cases and the leaflets were thickened and less mobile in 30%. Forty-five percent of the angiograms showed evidence of coronary orificial stenosis. The sinuses of Valsalva were significantly enlarged in 75% of the cases. Changes in dimensions of the aortic root were demonstrated more clearly by angiography than by echocardiography. In all anatomic specimens, a marked redundancy of the leaflets was observed and quantified. CONCLUSIONS: Our data demonstrate that the entire valvular apparatus is always affected by the so-called supravalvular stenosis. Anatomic restoration of the aortic root should ideally take into account all of the deformed components by enlarging all three sinuses of Valsalva at the sinotubular junction.

Adolescent↗
PubMed1997

CD4 monoclonal antibody administration in atopic dermatitis.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory dermatosis that probably involves a dysregulated activation of helper T cells, type 2 (Th2 cells). Severe refractory AD can be controlled by cyclosporine treatment. OBJECTIVE: We attempted to determine whether short-term CD4 monoclonal antibody (mAb) therapy could improve severe AD in adults. METHODS: The CD4 mAb, B-F5, was infused over 2 days in three patients with severe refractory AD and, for control purposes, in two patients with severe psoriasis. RESULTS: Administration of B-F5 was well tolerated, despite moderate first dose side effects. Clinical improvement was observed in two patients. In the third patient, a dramatic worsening occurred between 8 and 30 days after treatment, associated with an increased percentage of activated CD4+, CD25+, HLA-DR+, and CD45RO+ cells and peripheral blood eosinophilia. The same CD4 mAb administered to two patients with severe psoriasis induced marked clinical improvement of the lesions. CONCLUSION: Although CD4 mAb infusion may be potentially useful in the treatment of AD, the risk of aggravating the Th1/Th2 imbalance in AD should be considered in the design of future protocols.

Adult↗
PubMed1997

The morphologically tricuspid valve in hypoplastic left heart syndrome.

OBJECTIVE: Competence of the tricuspid valve is crucial for survival of children with hypoplastic left heart syndrome. We studied the morphology and topology of the valvar and subvalvar structures, trying to identify abnormalities which could impair valvar function. METHODS: A total of 82 specimens with hypoplastic left heart syndrome were examined pathologically. Measurements of valvar dimensions were taken, significant dysplasia of the valvar leaflets was noted and the muscular and tendinous supporting structures determined. The findings were correlated to the subgroups of hypoplastic left heart syndrome. RESULTS: Of the hearts, 10 (12%) showed a bileaflet right atrioventricular valve, 27 (33%) a moderately and 2 (2%) a severely dysplastic tricuspid valve. The majority of the abnormalities was found in hearts with a patent mitral valve. In 79% of the hearts with mitral atresia, the septal surface was concave instead of convex to the right ventricular lumen and the direct tendinous attachments of the septal leaflet replaced by a multitude of freestanding papillary muscles. The number of direct septal attachments was significantly higher in hearts with a patent mitral valve. CONCLUSIONS: The tricuspid valve in hypoplastic left heart syndrome can differ from the valve seen in normal patients. The subvalvar apparatus is different in hearts with mitral atresia, whereas dysplasia of the leaflets occurs more often together with mitral stenosis. These features should be considered in reconstructive operations as well as during diagnostic procedures.

Aortic Valve↗
PubMed1994

[Verruciform xanthoma of the penis].

Verruciform xanthoma (VX) usually occurs within the oral cavity, rarely in the genital areas. A case of VX on uncircumcised penis is reported in a 58 year-old man without prior history of sexual transmitted disease; histological features are characteristic and staining of the foam cells are positive with CD68 and negative with S100 protein. Etiological factors of the VX are uncertain and in the genital localizations a viral cause has not been proved.

Electrocoagulation↗
PubMed1994

Benign colonic ulcers associated with nonsteroidal antiinflammatory drug ingestion.

Nonsteroidal antiinflammatory drugs can be associated with benign colonic ulcers. The ulcers are easily diagnosed by colonoscopy, and, if uncomplicated, they are best treated by cessation of the nonsteroidal antiinflammatory drugs. Benign colonic ulcers should be included in the differential diagnosis of any patient who presents with gastrointestinal complaints and is taking nonsteroidal antiinflammatory drugs.

Aged↗
PubMed1993

[Subglottal stenosis following intubation in children].

BACKGROUND: Subglottal stenosis following intubation of children is infrequent, but significant. It is therefore necessary to know more about predisposing factors. MATERIAL AND METHODS: The files of all the 1,006 children who were intubated from 1982 to 1989 were studied. The following data were analysed: weight, height, locality of intubation, type and diameter of tube, reason for intubation, duration of intubation, delay and type of clinical signs of subglottal stenosis, treatment of this complication. RESULTS: Twelve children (1.5%) developed subglottal stenosis; 9 were 5 months to 7 years old; the other 3 were neonates, 2 of them with a very low birth weight. The disease responsible for intubation was neurologic in origin in 6 cases, respiratory in 4 and hemodynamic in 2. The tube used for 4 children was too large, based on standards for age and weight. The mean duration of intubation was 21.1 days (1-129 days). Primary failure to extubate usually revealed subglottal stenosis, which was assessed by laryngoscopy. It was necessary to reinsert a tube for a mean duration of 20.2 days (4-41 days) in 11 of the 12 children; all patients received corticosteroids. 6 children required tracheostomy for 37 to 365 days. Dilation was necessary in 7 children. Finally, 9 children fully recovered, 1 has an asymptomatic persistent stenosis, 1 is still intubated with severe neurologic sequellae and 1 died accidentally, probably as a result of obstruction by tube dilation. CONCLUSION: Stenosis remains a severe complication of intubation. The diameter of the tube is probably the most aggressive factor. It seems preferable to use a smaller, therefore cuffed tube and to secure the airways, if necessary, by inflating the cuff.

Child↗
PubMed1992

Keratinocyte migration is partially supported by the cell-binding domain of fibronectin and is RGDS-dependent.

Fibronectin (FN) plays a key role in cell attachment, embryonic development, and wound healing. In this respect, it is known that FN promotes keratinocyte migration. The aim of this study was to examine specific FN domains (120-kD cell-binding fragment, 45-kD collagen fragment, and 40-kD heparin fragment) and a biologically active peptide within the molecule (RGDS) for their ability to influence human keratinocyte (HK) locomotion. HKs were plated on gold salts coated with different substrates (type IV collagen, FN with or without the RGDS peptide, and the three FN fragments). After 20 h, locomotion tracks were quantified by computer-assisted image analysis that determines the area of each microscopic field occupied by migration tracks, a so-called migration index (MI). MIs on type IV collagen and FN were 39.14 +/- 2.8% and 30 +/- 0.4%, respectively. The maximal MIs on the collagen-binding domain and heparin-binding domain of FN were similar to our negative controls (plastic and albumin): 3 +/- 1%. In contrast, the maximal MI on the cell-binding fragment of FN was 18.45 +/- 2.1%. The effect of the cell-binding domain on keratinocyte motility was found to be dose dependent. Moreover, we could specifically inhibit the FN-driven locomotion using the RGDS sequence contained in the cell-binding fragment. We did not observe a synergistic effect (i.e., a higher MI) when we added the three fragments in a same dish. These results suggest i) that the cell-binding fragment of FN partially supports HK locomotion, ii) that other untested FN domain(s) should act in synergy with the cell-binding fragment to promote keratinocyte locomotion, or alternatively iii) that the FN function of promoting cell migration resides within the FN cell-binding domain, but the proper presentation of this domain to the cell requires an intact, native FN molecule, and iv) that the RGDS sequence is essential for HK movement.

Amino Acid Sequence↗
PubMed1992

[Fibronectins].

Fibronectins are complex glycoprotein macromolecules whose molecular weight is 440 kilodaltons. These proteins, found throughout the body, are soluble in biological fluids and insoluble in connective tissue. They contribute to tissue morphogenesis through multiple interactions with cells and extracellular matrix components. Fibronectins play a key role in cell attachment and remodeling during embryonic development, in cell migration and anchorage during wound healing, and in immune responses. This review discusses the structure of fibronectins, their integrin cell receptors, their biologic properties and their implications for diseases.

Cell Adhesion↗
PubMed1991

Output grating couplers on planar optical waveguides as direct immunosensors.

We demonstrated the feasibility of using integrated optical output grating couplers in direct immunosensing. We monitored as functions of time, first the adsorption of an antigen (Ag) on the waveguide's surface, and subsequently, the binding of the corresponding antibody (Ab), i.e. the formation of the immuno-complex Ag-Ab. The Ag was human immunoglobulin G (h-IgG), and the Ab was rabbit anti-h-IgG. We also studied the adsorption of avidin. The refractive indices nF', thicknesses dF', and surface coverages gamma of the adsorbed adlayers and of the immuno-complex Ag-Ab, respectively, were determined.

Adsorption↗
PubMedDate not supplied

[Myocardial revascularization interventions].

UNLABELLED: Elective coronary artery bypass surgery (CABG) can be performed with low operative mortality. There is a controversial discussion whether short- and long-term results of CABG can justify this procedure even in elderly patients. MATERIAL AND METHODS: We retrospectively evaluated the clinical profile, operative procedure, postoperative short- and long-term results of 1127 patients over 70 years of age who underwent myocardial revascularization between January 1985 and December 1996. RESULTS: Mean age was 73.9 years. In 1996, septuagenarians represented 21.5% of our operated coronary patients, when compared with 6.4% in 1985. Analysis of risk factors showed an increasing prevalence of renal failure, obesity, hyperuricemia and a history of smoking. Preoperatively 87% of our patients were in NYHA-class III and IV. The percentage of emergent operations decreased over the observed period by 10.3%. Internal mammary artery was used with increasing frequency (44.8% in 1985-92 vs. 61.5% in 1993-96). The number of simultaneous valve replacements increased, too. Postoperatively, we noted rising incidence of respiratory failure (17.1%) and neurological disorders (13.7%). On the other hand, the need for intraaortic balloon pumping and hemofiltration declined by 6.6% and 2.9%. Perioperative mortality (< or = 24 h) was 3.65%, hospital mortality (< or = 30 days) was 9.64%. Actuarial 1 year at was 82% (+/- 4.3%), and 65.7% (+/- 3.8%) at 5 years. CONCLUSIONS: Our data suggest that CABG can be performed in septuagenarians with an acceptable operative risk. Since the large majority of patients improve symptomatically, surgery is the recommendable option for a growing number of elderly patients suffering from severe angina.

Age Factors↗