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Biomedical subjects

D Keller

Publications and source records attributed to D Keller.

At least 55 records · Page 3Linked to original sources
PubMed1987

Differential polarization imaging. I. Theory.

A theory of differential polarization imaging is derived using Mueller calculus. It is shown that, for any arbitrary object, 16 images (in general different) can be obtained by combining different incident polarizations of light and measuring the specific polarization components transmitted or scattered by the object. These are called the Mueller images of the object. Mathematical expressions of these images for an object of arbitrary geometry are derived using classical vector diffraction theory and the paraxial and thin lens approximations. The object is described as a collection of point polarizable groups. The electromagnetic fields are calculated using the first Born-Approximation, but extension of the theory to higher-order approximations is shown to be straightforward. These expressions are obtained for the transmission, or bright-field, geometry, and the scattering, or dark-field, configuration. In both cases, the contributions of scattering, absorption, and background illumination to the Mueller images are characterized. The contributions of linear dichroism, circular dichroism, and linear and circular intensity differential scattering to certain Mueller images are established. It is shown that the Mueller images represent a complete two-dimensional mapping of the molecular anisotropy of the object.

Mathematics↗
PubMed1986

Laboratory procedures in adenoviruses. XII. Comparison of five ELISA methods for demonstration of hexon antigen.

To demonstrate adenovirus hexon, four different arrangements of a four-layer ELISA, to be performed with commercially available reagents, were compared with a three-layer ELISA. After evaluation of specific and control reagents and their dilutions, the guinea pig/rabbit or the rabbit/chicken method were equally practicable and sensitive as the three-layer method with rabbit serum and superior to two other methods. By testing about 100 stool samples and 74 throat swabs containing adenoviruses, it turned out that the sensitivity (1 ng/ml hexon) appears satisfactory for stool specimens in adenovirus enteritis of infants, but is much less sensitive than isolation in cell culture for adenoviruses in throat swabs. As confirmatory test, specimen were incubated with an adenovirus rabbit antiserum or normal serum and then tested.

Adenoviridae Infections↗
PubMed1986

Validation of the Functional Assessment Inventory against a multidisciplinary home care team.

Systematic multidimensional assessment techniques such as the Functional Assessment Inventory (FAI) are increasingly used with the elderly for outcome measurement, prediction of service needs, and accurate description for comparative purposes. The FAI is a structured interview followed by a rating process which compares patient status against standard descriptive phrases. Patients are assessed in five areas: mental health, physical health, social resources, economic resources, and activities of daily living (ADL). The validity of the FAI was tested by comparing ratings of patient health obtained by a single investigator using only the instrument with ratings obtained by consensus from an interdisciplinary home care team providing long-term care for the patients studied. An excellent level of agreement (weighted kappas from .583 to .780) was found in all areas studied. A single significant difference in ADL rating with a high correlation coefficient (r = .85) was interpreted as due to a difference between the single rater and the team in the definition of ADL. The ease of obtaining summary ratings from clinical personnel suggests that further exploration of this rapid quantification of patient health is warranted.

Activities of Daily Living↗
PubMed1985

[New viewpoints on the prognostic index in malignant melanomas].

Investigation of anamnestic development, Tumor types, levels of invasion (Clark), tumor thickness (Breslow), mitotic index (Schmoeckel and Braun-Falco) in 407 (without lentigo maligna and preinvasive superficial spreading melanoma 317) cases revealed an interdependence between thickness and mitotic index. This is a theoretical argument against the "prognostic index" as a product of both these parameters.

Humans↗
PubMed1985

Imaging of optically active biological structures by use of circularly polarized light.

If an optically active (chiral) sample is placed in a microscope and illuminated with circularly polarized light, an image can be formed that is related to the circular dichroism of each feature of the sample. A theoretical investigation has been done for the circular differential image obtained by subtracting the images formed under right- and left-circularly polarized light. Two types of differential images are possible: (i) dark-field images formed from light reflected or scattered by the sample and (ii) bright-field images formed from light transmitted through the sample. The sign and magnitude of each feature in a circular differential image strongly depend on the structure of the sample. The dark-field circular differential images are most sensitive to large features with dimensions similar to the wavelength of illumination whereas the bright-field images are most sensitive to the short-range molecular order. Applications of circular differential imaging may include clinical fingerprinting of normal and transformed cells and structural analysis of individual cellular components.

Circular Dichroism↗
PubMed1985

[Total duodenal diversion by fundo-jejunostomy with Roux-Y-loop in the treatment of severe postoperative recurrent reflux esophagitis].

Fundo-jejunostomy with a 60 cm long Roux-en-Y loop removes almost all symptoms in severe postoperative recurrent reflux esophagitis. We analysed 12 own cases and compared them with those published in literature. 90% of most satisfactory results were obtained. Nevertheless indication for fundo-jejunostomy must be discussed and limited to those cases, which do not respond to medical treatment.

Duodenum↗
PubMed1984

Danazol treatment increases serum enzyme levels.

Six of seven women treated for endometriosis with daily administrations of 800 mg of danazol over 4.7 to 9 months developed one or more mildly abnormal serum enzyme levels. All seven patients had normal pretreatment enzyme levels and were evaluated after 2.5 to 5 months of drug therapy and again 1 to 2.5 months following completion of drug therapy. Danazol therapy was associated with statistically significant increases in the following serum enzyme levels: creatine phosphokinase, lactate dehydrogenase, serum glutamic oxaloacetic transaminase, and serum glutamic pyruvic transaminase. Mean serum enzyme increases ranged from 25% to 86% greater than the mean pre-drug-therapy level. Alkaline phosphatase levels were not altered by the danazol treatment. Following completion of danazol therapy, all enzyme levels were within the normal range except serum glutamic pyruvic transaminase, which was approaching normal. High-dose danazol treatment (800 mg daily) is associated with mild elevations of specific serum enzymes, and these changes appear to resolve spontaneously after cessation of treatment.

5'-Nucleotidase↗
PubMed1984

Adverse histopathologic effects of chemotherapeutic agents in childhood leukemia and lymphoma.

Pathologic material from 84 children with leukemia or lymphoma who died and were autopsied at the University of Wisconsin Hospital between 1967 and 1980 was reviewed to assess the adverse tissue changes due to the chemotherapy administered. In each case the histopathologic findings were correlated with the chemotherapy given. Individual drug dosage is administered (per m2) correlated with the adverse tissue findings at autopsy. Data presented suggest that the drug dose administered should be correlated not only with tumor response but also with tissue effects (some of which produce no noticeable, immediate, clinically apparent changes) to decrease the likelihood of producing irreversible tissue changes.

Adolescent↗
PubMed1984

[Acute hemorrhagic necrotizing pancreatitis. Analysis of 58 patients].

The authors stress the therapeutic importance of peritoneal lavage for eliminating toxic substances from the abdominal cavity. In cases of a stenosing papilla or an impacted gallstone, endoscopic papillotomy and stone extraction are recommended. The indication for surgical interventions, like nekrosectomy or segmental resection of the pancreas, are discussed in detail. In case of diffuse recurrent peritonitis the technique of the "open abdomen" should be taken into consideration. The results of 44 resections and 14 necrosectomies are represented. The overall mortality rate comes up to 35 or 40% respectively.

Acute Disease↗
PubMed1983

[Surgical treatment of acute necrotizing hemorrhagic pancreatitis. Analysis and prospective deductions on 58 cases].

Three degrees of severity could be recognized in 58 patients operated upon for severe acute hemorrhagic pancreatitis, based on results of intensive care, particularly anti-shock therapy, wide peritoneal lavage, and possible need for endoscopic relief of sphincter of Oddi obstruction due to a stone. The principal parameters evaluated were clinical and biological features and the course of the affection. As a result of these data, 44 pancreatic resections of variable extension and 14 excisions of necrotic tissues were performed. Results of these two types of operations, as well as the dominant causes of postoperative and secondary deaths, are analyzed in detail. The indications for surgery are discussed, together with the tactical methods to be applied as a function of the general condition and the detailed study of the pancreas and the state of the adjacent organs. Particular importance should be attached to the presence of respiratory insufficiency. The possible need for routine biliary external drainage is discussed, and the major role played by parenteral nutrition, which should be initiated as early as possible, is emphasized. These findings suggest that two fundamental principles should guide surgery of acute hemorrhagic pancreatitis: the need for surgery in selected cases, though over-aggressive operations should be avoided, and, more particularly, the concept, to be shared of the need for repeated operations, enabling avoidance of excessive procedures during initial surgery.

Acute Disease↗
PubMed1983

[New vagotomy technics].

Various new more extensive operative procedures have been proposed with the aim of increasing efficacy of vagotomy and ensuring maximum neurotomy. Though based on the principle of neurotomy as accomplished by highly selective vagotomy, it is completed or combined with a seromyotomy along one or both sides of the lesser curvature or with one in the cardiofundal region. Technical aspects of these different methods are discussed.

Humans↗