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Biomedical subjects

D Beyer

Publications and source records attributed to D Beyer.

At least 37 records · Page 2Linked to original sources
PubMed1997

Reduced protein adsorption on plastics via direct plasma deposition of triethylene glycol monoallyl ether.

The direct plasma-induced deposition of tri(ethylene glycol) monoallyl ether is reported. RF plasma polymerization of this monomer was carried out under both continuous wave (CW) and pulsed plasma operation. The major focus of this work was optimization of the degree of retention of the C-O-C bonds of the starting monomer during the deposition process. This successfully was accomplished using low RF power during the CW runs and low RF duty cycles during the pulsed plasma experiments. Spectroscopic analysis of the plasma films revealed a strong dependence of film composition on the RF power and duty cycles employed. In particular, an unusually high level of film chemistry compositional control was demonstrated for the pulsed plasma studies, with film composition varying in a steady, progressive fashion with sequential changes in the ratios of plasma on to plasma off times. This film chemistry controllability is demonstrated despite the relatively low volatility of the starting monomer. The utility of this plasma deposition approach in introducing polyethylene oxide (PEO) structures on solid substrates was evaluated via protein adsorption studies. Radiolabeled bovine albumin adsorption was studied on plasma-modified poly(ethylene teraphthalate) (PET) substrates. Dramatic reductions in both initial adsorption and retention of this protein were observed on PET samples having maximal PEO content relative to its adsorption on untreated PET surfaces. Good stability and adhesion of the plasma films to the underlying PET substrates were observed, as evidenced from prolonged immersion of plasma-treated surfaces in aqueous solution. Overall, the results obtained from the present work provide additional support for the utility of one-step plasma process to reduce biological fouling of surfaces via deposition of PEO surface units.

Animals↗
PubMed1995

Significance of radiological diagnosis for detection and staging of inflammatory abdominal aortic aneurysm.

Operative morbidity and mortality are elevated in patients with inflammatory abdominal aortic aneurysm. Preoperative identification of inflammatory abdominal aortic aneurysm. the detection of the proximal level and of adhesions to adjacent structures are important for surgical management. The sensitivity and specificity of ultrasonography and computed tomography (CT) for identification and staging in 13 patients with inflammatory abdominal aortic aneurysm were studied. Preoperative radiological diagnoses were validated by intraoperative findings. Correct identification of inflammatory abdominal aortic aneurysm could be achieved in 85% by the use of CT and in 62% by ultrasonography. The proximal level of inflammatory abdominal aortic aneurysm was correctly determined by CT in all patients and by ultrasonography in 62%. Using a transperitoneal approach, the condition was considered inoperable in two patients as a result of the suprarenal extent of the aneurysm and because of unremovable adhesions in two other cases. In the latter pair, it was impossible to predict inoperability by radiological findings. Sensitivity (85%) and specificity (100%) of standard radiological techniques to identify inflammatory changes are high. Inoperability caused by suprarenal extent could be detected correctly by routine radiological procedures. However, identification of dense adhesions appears uncertain.

Adult↗
PubMed1994

How the ribosome moves along the mRNA during protein synthesis.

The movement of a ribosome along the mRNA was assessed by the following experimental strategy. mRNAs were synthesized which contained a short coding sequence with at least four codons and a 32P label at one end and an oligo(C) sequence at the other end. When these mRNAs were fixed on the ribosome with tRNAs specific for the defined codons, the oligo(C) stretches were partially outside of the ribosome, whereas the labeled ends were inside the ribosome and thus protected. The overhanging oligo(C) regions were trimmed with the cytidyl-specific RNase CL3 identifying the nucleotides of the mRNAs, which emerged from the ribosome. An mRNA enters the ribosome at nucleotide 18 +/- 1, when counting starts at the first nucleotide of the P-site codon, and leaves the ribosome at nucleotide -21 +/- 2. The ribosome does not move at either side upon A-site occupation but does so at both sides simultaneously upon translocation. The results further indicate that most of the mRNA stretches downstream and upstream of the coding region are not required for the translocation reaction. It is therefore likely that the tRNAs are pulling the mRNA through the ribosome via codon-anticodon interactions in the course of translocation.

Amino Acid Sequence↗
PubMed1994

[Multiple microembolization caused by elemental mercury].

Elemental mercury is usually found in the vascular system following intravenous injection. It is distributed in the body in two different ways, which are described in detail. We report the case of a 39-year-old male, who injected elemental mercury in his cubital vein in a suicide attempt. This fact was detected accidentally during clinical treatment. Microemboli of metallic mercury were found in the lungs, liver, spleen, kidneys, central nervous system and other organs. A high serum concentration of dissolved and oxidized mercury was detected. No signs of chronic mercury intoxication in the form an organic functional disturbance were obvious.

Adult↗
PubMed1993

Current trends in state child labor legislation and enforcement.

There is much current child labor law activity, none of it reflecting concern with occupational health hazards. The focus of the legislation is on time for and dedication to education as youth's foremost priority. The only areas of state legislative change that could affect children's health and safety in the workplace are a general movement toward monetarily increasing fines and penalties and some minor inclusions of agricultural restrictions on young workers. Enforcement efforts are in all cases a primary indication of state commitment to child labor law protections, and these efforts are decreasing.

Adolescent↗
PubMed1993

[Ultrasound diagnosis of the acute abdomen].

In addition to plain X-ray of the abdomen, ultrasonography has proven to be an accurate complementary imaging method in acute abdominal disorders. It may furnish not only additional information but also the final diagnosis in many cases (i.e. acute cholecystitis, pancreatitis, diverticulitis, appendicitis and gynecological diseases). Ultrasound is the method of first choice especially in children, adolescents, young women and when inflammation appears to be the reason for acute abdominal pain. In this paper, the main indications for ultrasound in acute abdominal diseases are pointed out. The most common diseases are shown with their typical ultrasound appearances in short overviews. Particular reference is made to a critical approach, emphasizing relevant further investigations.

Abdomen, Acute↗
PubMed1993

[Sonography of acute appendicitis. A 5-year prospective study of 2074 patients. 2].

High-resolution real-time ultrasound (US) with a 5 MHz transducer has proved to be an important method in the diagnosis of acute appendicitis. In a prospective study we examined 2074 unselected patients with suspected appendicitis to assess the diagnostic and epidemiological value of US. According to the clinical diagnosis females aged 10 to 30 represented the majority of suspected cases. Appendicitis was most often proved in male patients aged 15-30 years. The prevalence of acute appendicitis in childhood is lower (7%) than in elderly patients (33%). US enables the diagnosis of acute appendicitis with a sensitivity of 91%, a specificity of 98% and an overall accuracy of 97%. For differential diagnosis US demonstrates other diseases that mimic acute appendicitis. Thus it is possible to reduce the negative appendectomy rate particularly in children by revealing mesenteric lymphadenitis or terminal ileitis and in young women by directing attention to gynecological diseases.

Acute Disease↗
PubMed1992

[Radiologic diagnosis of maxillary sinus aspergillosis].

Aspergillosis of the maxillary sinuses shows an increasing incidence in even otherwise healthy patients. Next to inhalation as the mode of infection, a dental root canal filling with an orosinusal fistula can be the cause. As most infections remain initially undetected or underestimated as common sinusitis, early diagnosis must be achieved. Standard X-ray of the paranasal sinuses, conventional tomography as well as CT scans are of major importance. Centrally located hyperdense opacifications are a good criterion and can be best seen in CT. Even when the case has not progressed too much, radical surgery combined with Amphotericin B therapy is still the treatment of choice since the infection may progress rapidly.

Adult↗
PubMed1991

[Acute adverse effects and complications of central venous digital subtraction angiography (DSA). Results of 2,600 studies].

Side-effects and complications from 2,600 intravenous digital-subtraction-angiographies (IV-DSA) are reported. All studies were performed in a standardized technique using a non-ionic contrast agent (Iopromid 370 mg J/ml). Side-effects or complications were noted in 2.5% of all IV-DSA. Most often nausea (0.92%), urticaria (0.5%), angina pectoris (0.5%) and symptomatic alterations of blood-pressure (0.27%) were recorded. 8.4% of all reactions occurred with a delay of at least one hour. All side-effects and complications resolved, partly under symptomatic therapy. In one (0.04%) out of 2,600 studies a severe allergoid reaction occurred, affording intensive-care therapy. With proper patient selection and a suitable technique, IV-DSA may be regarded--within the angiographic methods--as a procedure of relatively low risk.

Aged↗
PubMed1991

[Complications after percutaneous transluminal angioplasty and vascular surgery].

Percutaneous transluminal angioplasty (PTA) is an accepted technique in the treatment of occlusive vascular disease. We report complications associated with balloon catheter dilatation and their treatment in the period from 1. 1. 1986 to 31. 3. 1990. Complications were found at the site of dilatation and the site of insertion of the catheter, mostly in the pelvic and femoral region. Surgical correction was successful in all patients, however three patients died postoperatively of acute myocardial ischemia. To avoid these complications close co-operation between the radiologist performing the dilatation and the vascular surgeon managing the complications should be assured.

Aged↗
PubMed1990

Empyema after pneumonectomy--empyema window or thoracoplasty?

369 pneumonectomies carried out within the years 1981 to 1988 and their empyema complications form the basis for a retrospective analysis to assess the outcome of treating pneumonectomy cavity empyema by window healing. During the same period 31 empyema after 322 pneumonectomies to treat bronchial carcinoma are investigated in more detail as far as their therapeutic modalities are concerned. 20 patients received a thoracic window. 18 of 31 patients (58%) could be cured, and 9 of these were in the thoracic window group. The hospital mortality of empyema patients after pneumonectomy amounted to 42%. In an historical comparison no progress could be recognized in the treatment of this septic complication.

Bronchial Fistula↗
PubMed1990

[Sonography in suspected appendicitis: a decisive factor in diagnosis and therapy? Results of a prospective study of 669 patients].

The appendectomy-rate in the Federal Republic of Germany is decreasing. German surgeons have begun to refuse appendectomy if there are no signs of acute inflammation. Preoperative assessment of patients with right lower quadrant pain has acquired new significance. The authors report on 2 years of experience with routine use of high-resolution ultrasonography in 669 cases of suspected acute appendicitis. Only 101 patients (= 15.1%) turned out to be suffering from acute appendicitis. Ultrasonography evaluation was found to have a sensitivity of 84.2%, a specificity of 96.8% and an overall accuracy of 94.9%. Ultrasonography was also useful in detecting mimicking diseases of acute appendicitis. Sonography should help to rule out severe disease in the frequent cases of functional abdominal pain.

Acute Disease↗
PubMed1988

Digital subtraction angiography: the intravenous approach.

With further improvement of digital subtraction angiography (DSA) equipment, and the development of sophisticated soft-ware programs, the intravenous approach again has become an promising diagnostic alternative in certain clinical settings, if the patient's cardiac output is not severely diminished. In many cases an additional arterial study is not necessary. The diagnostic results, advantages and limitations of the intravenous approach in imaging the brachiocephalic, renal and peripheral vessels are discussed.

Angiography↗