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F Koenig

Publications and source records attributed to F Koenig.

At least 37 records · Page 2Linked to original sources
PubMed1998

Spectroscopic measurement of diffuse reflectance for enhanced detection of bladder carcinoma.

OBJECTIVES: To assess the diagnostic potential of diffuse reflectance spectroscopy for the detection of bladder carcinoma during cystoscopy. Our hypothesis is that neovasculature in neoplastic (dysplastic and malignant) regions will lead to a blood absorption "signature" that is different from that of normal tissue. METHODS: Diffuse reflectance measurements have been performed in 14 patients undergoing mucosal biopsies or transurethral resection of a bladder tumor. A quartz optical fiber was advanced through the working channel of a cystoscope and placed in gentle contact with the bladder surface. A standard cystoscopy xenon light source was used for illumination and the reflectance spectra were recorded using an optical multichannel analyzer (OMA) system. From the spectra, the relative concentrations of hemoglobin (Hb), oxyhemoglobin (HbO2), oxygen saturation (HbO2%), and the total amount of blood (arbitrary units) were calculated to assess their usefulness in differentiating between neoplastic and benign bladder areas. RESULTS: The spectra of 26 bladder areas (9 malignant areas including 4 carcinomata in situ, 2 dysplastic lesions, and 15 benign areas) have been analyzed. Only the total amount of blood was a useful parameter for the differentiation between neoplastic and benign bladder areas. The sensitivity, specificity, and positive and negative predictive values of this method for neoplastic tissue were found to be 91%, 60%, 63%, and 90%, respectively. CONCLUSIONS: The measurement of diffuse reflectance is a fast, simple, and noninvasive method which allows in vivo determination of bladder blood perfusion. The total blood concentration was increased in neoplastic bladder tissue, making it a tool for tissue diagnosis. The relatively low specificity is a result of inflammatory areas also exhibiting an increased total blood concentration. This pilot study encourages further studies to assess the usefulness of reflectance measurements for enhanced detection of bladder cancer.

Aged↗
PubMed1998

The percentage of free prostate specific antigen is an age-independent tumour marker for prostate cancer: establishment of reference ranges in a large population of healthy men.

OBJECTIVE: To define the reference range for the ratio of free to total prostate-specific antigen (fPSA%) in a population of healthy men with no clinically evident prostate cancer and to assess the influence of age on this tumour marker, thus determining the utility of fPSA% in enhancing the discriminatory power of PSA to differentiate healthy men and patients with benign prostatic hyperplasia from those with prostate cancer. SUBJECTS AND METHODS: In a prospective cohort study between May and August 1996, 1160 white men aged 20-89 years (957 were 40-69 years old, 82% of all subjects) from nine European and eight non-European countries were assessed. None of the participants who had a history of prostate cancer had undergone prostatectomy. A standard clinical examination including a digital rectal examination was performed to exclude the presence of prostate cancer. Transrectal ultrasonography was not an inclusion criterion, as it was not available in every case. Total PSA (tPSA) and free PSA (fPSA) were determined in 61 laboratories using the appropriate Enzymun-Test for tPSA and fPSA (Boehringer Mannheim Diagnostics, Mannheim, Germany). Serum tPSA, fPSA and fPSA% were then assessed as a function of the subjects' age. RESULTS: The serum tPSA and fPSA were significantly different among age decades 2-8 (P < 0.001), with increasing median values, indicating that both variables depend on age. The recommended upper reference limit (95th percentile) for tPSA is 1.78 ng/mL for men aged 30-39 years, 1.75 ng/mL for 40-49 years, 2.27 ng/mL for 50-59 years, 3.48 ng/mL for 60-69 years and 4.26 ng/mL for 70-79 years. The fPSA% was not significantly different between decades 3-8 (P = 0.06). Those aged 20-29 years had a slightly higher median value (P = 0.03) than the other age groups. The recommended lower reference limit (fifth percentile) for fPSA% is 12.6%. CONCLUSION: The fPSA% for clinically relevant age groups in healthy men was independent of age, which simplifies the use and interpretation of this relatively new tumour marker.

Adult↗
PubMed1998

Preventive healthcare in physicians and attorneys.

Physicians make recommendations to their patients on a daily basis regarding tests and procedures. However, no research has evaluated physicians use of similar tests for their own health and well-being. This article reviews a comparison between 55 male physicians and 55 male attorneys of similar age regarding their use of the annual physical examination and routine screening tests. In several areas, the results indicate that physicians do not participate in routine tests and procedures as well as do their legal counterparts. Possible explanations for this physician behavior are included in the discussion segment of the article.

Adult↗
PubMed1997

Analytical aspects regarding the measurement of metalloproteinases and their inhibitors in blood.

OBJECTIVE: Both in vitro and in vivo investigations have shown that the balance between matrix metalloproteinases (MMP) and the tissue inhibitors of metalloproteinases (TIMP) seems to be important in physiological and pathological processes which involve tissue remodeling and repair. DESIGN AND METHODS: In order to investigate the analytical reliability of new commercial ELISA tests. BIOTRAK test kits (Amersham Int.) were used for the determination of metalloproteinase-1 (MMP-1), tissue inhibitor of metalloproteinase-1 (TIMP-1), and the MMP-1/TIMP-1 complex in blood. RESULTS: The detection limits and the precision data were in the usual ranges of ELISA tests so that concentrations found in blood could be determined reliably. Since all three analytes were lower in heparin plasma than in serum or EDTA plasma, heparin plasma was selected as the specimen of choice. Measurement of diluted samples gave higher values than those of undiluted native plasma samples because the inhibitory effects of specific/unspecific inhibitors or other matrix components were apparently reduced. To obtain comparable data from different laboratories, the predilution of samples must be defined. We recommend to use diluted plasma samples of 1:5, 1:21, and 1:11 for the determination of MMP-1, TIMP-1, and the complex MMP-1/TIMP1, respectively. The preliminary upper 95% reference limits measured under these conditions in healthy subjects (40 females: 40 males) were 14.4 micrograms/L for MMP-1 in females, 20 micrograms/L for MMP-1 in males. 1668 micrograms/L for TIMP-1 and 116 micrograms/L for the complex MMP-1/TIMP-1. CONCLUSION: The study has shown that the BIOTRAK test combinations for MMP-1, TIMP-1, and MMP-1/TIMP-1 complex allow a reliable measurement of the analyte concentrations in heparin plasma. In order to avoid preanalytical misinterpretations only heparin plasma samples in defined dilutions should be used.

Adult↗
PubMed1997

[Radiotherapy of macular lesions in age-related macular degeneration (AMD): initial results of a study inducted in Lyon, France].

PURPOSE: To evaluate irradiation effects on functional signs and choroidal neovascular lesions in age-related macular degeneration (AMD) that does not respond to laser therapy. MATERIALS AND METHODS: Since 1994, 250 consecutive AMD patients were treated by two radiotherapy teams for subfoveal neovascular lesions. At the end of September 1996, 52 patients were evaluable with a 1-year follow-up. Group 1 (Département de Radiothérapie Oncologie, Centre Hospitalo-Universitaire Lyon Sud) included 26 patients who were treated with a lateral beam of 6 MV photons. The irradiation doses were 20 Gy in five fractions for small lesions and 28.8 Gy in eight fractions for larger lesions. Group 2 (Centre Oncologie Radiothérapie Saint-Jean) was composed of 26 patients treated with a mini-beam of 25 MV photons via lateral arc-therapy. Beam diameters (14 and 18 mm) were adapted to the lesion size. The total dose was 16 Gy in four fractions or 20 Gy in five fractions. RESULTS: Functional and anatomical results were assessed at 3, 6, 9 months and 1 year after radiation therapy. Stable visual acuity was observed in 44% (23/52) of the patients and visual acuity was improved in 35% (18/52) of the patients at 6 months. Good functional results reached 79% (41/52) at 6 months and 74% (17/23) at 12 months. A significant decrease (> 10%) of the membrane was present in 46% (16/52) of the cases at 6 months and in 65% (15/23) of the cases at 12 months. There was no statistical difference between the two groups and dose levels. All severe complications (1 cataract, 3 dilated choridal vessels, and 2 papillitis) occurred in group 1. CONCLUSION: Though it is too early to conclude on the best dose level, radiotherapy of subfoveal neovascular lesions of AMD that cannot be treated via laser therapy provides encouraging results. The technique used must be very precise to adequately irradiate the fovea and spare surrounding sensitive areas. Further studies and trials involving patients' randomization are necessary to confirm these preliminary results.

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PubMed1997

Elimination of serum free and total prostate-specific antigen after radical retropubic prostatectomy.

Elimination kinetics of serum total and free prostate-specific antigen were studied for a ten days course after radical retropubic prostatectomy on 11 patients suffering from organ confined prostate cancer. Samples were taken before operation, immediately after finishing the operation and 1, 2, 3, 4, 5, 6 h after prostatectomy and then once a day for the following ten days. The measurements were performed with AxSym assays from Abbott Laboratories. The elimination of both total and free prostate-specific antigen followed a biphasic kinetics. In the fast phase, the average of the individual elimination half-lives of total and free prostate-specific antigen amounted to 6.3 h (SD = 6.1 h; range: 0.55 to 37.1 h) and 0.57 h (SD = 0.18 h; range: 0.22 to 0.89 h), respectively. In the slow phase, total prostate-specific antigen disappeared with an average half-life of 85.6 h (SD = 11 h; range: 47.2 to 261.7 h) and free prostate-specific antigen with an average half-life of 14.4 h (SD = 10.4 h; range: 2.4 to 30.3 h). These results might be significant for the use of free and total prostate-specific antigen and its ratio as a diagnostic and prognostic tool.

Aged↗
PubMed1996

Laser induced autofluorescence diagnosis of bladder cancer.

PURPOSE: We assessed the ability of laser induced autofluorescence to differentiate malignant from nonmalignant bladder lesions. MATERIALS AND METHODS: We studied 53 patients with bladder cancer undergoing mucosal biopsies or transurethral resection of a bladder tumor. A quartz optical fiber was advanced through the working channel of a cystoscope and placed in gentle contact with the bladder. Tissue fluorescence was excited by 337 nm. light pulses (nitrogen laser). One fiber was used for transmission of the excitation and emission (fluorescence) light. An optical multichannel analyzer system was used to record fluorescence spectra of the sites of interest. RESULTS: We analyzed the fluorescence spectra of 114 bladder areas (1 carcinoma in situ as well as 28 malignant, 35 inflammatory, 7 dysplastic, 1 squamous metaplastic and 42 normal areas). These lesions included 44 difficult to diagnose suspicious tumors (11 malignant and 33 nonmalignant). We developed an algorithm that used the I385:I455 nm. fluorescence ratio to distinguish malignant from nonmalignant lesions, including inflammatory areas. By analyzing the data on all 114 lesions, we noted the sensitivity, specificity, and positive and negative predictive values of this method for differentiating malignant from nonmalignant bladder lesions to be 97, 98, 93 and 99%, respectively. CONCLUSIONS: Under excitation with 337 nm. light a clear differentiation between malignant and nonmalignant bladder tissues can be made using the I385:I455 nm. autofluorescence ratio.

Aged↗
PubMed1993

Posterior uveitis, paraneoplastic encephalomyelitis and auto-antibodies reacting with developmental protein of brain and retina.

We report a 68-year-old woman who presented with posterior uveitis, cerebellar ataxia, dysautonomia, peripheral neuropathy and undifferentiated carcinoma. Autopsy showed slight brain inflammatory changes and severe Purkinje cell degeneration. By immunocytochemistry, the serum and CSF contained antibodies that reacted with the cytoplasm of cells in the brain and retina of rat. Some neurons and glial cells were stained. However, the most labelled cells were immature cells of the subventricular layers of the dentate gyrus, olfactory bulb and lateral ventricles. In rat retina, the plexiform layers and cells of the inner granular layer were stained. E15 rat embryo showed diffuse staining of post-mitotic cells and process in the central and peripheral nervous system. With the patient's IgG, various bands of 45, 60, 70 and 135 kDa apparent molecular weight were demonstrated on immunoblots of adult human, adult and E15 embryonic rat brain and rat and bovine retina. Eluates of tissue bound IgG labelled the same bands.

Aged↗
PubMed1990

The pretear characteristics of pigment epithelial detachments. A study of 40 eyes.

Retinal pigment epithelial tears are a major complication of pigment epithelial detachment (PED) in the elderly. We observed the pretear process of PED in 38 patients (40 eyes) to identify characteristic angiographic changes. Before the tear occurred, the filling pattern of the PED underwent alterations, including an increase in the size and a modification in the shape of the PED (27 eyes); the development of notches (14 eyes); and the onset or increase of subretinal fluid, hard exudates, and/or hemorrhages (30 eyes). The most noteworthy feature was the uneven filling of the PED, with a remarkably hypofluorescent central area that remained dark until the late angiographic frames (24 eyes). Conversely, hyperfluorescence appeared early at the margins of the PED, increased progressively, and sometimes demonstrated a crenated edge. The high risk of tearing indicates that laser treatment of the retina should be considered carefully in the presence of these angiographic features.

Aged↗
PubMed1990

Occult subretinal new vessels in age-related macular degeneration. Natural History and early laser treatment.

Little information is available on the natural history and no data have been published on laser treatment for occult neovascularization in age-related macular degeneration. The visual and angiographic outcomes were analyzed in 156 patients (82 untreated eyes; 81 treated eyes) with occult neovascularization who were followed for 1 to 8 years. Early laser treatment decreased visual acuity to less than 20/200 in 31 of the treated eyes (38%) compared with 20 of the untreated eyes (25%). Three years after the onset of symptoms, 24 treated eyes (29%) and 31 eyes untreated eyes (38%) retained 20/50 visual acuity or better, whereas their respective initial visual acuities were not statistically different. Severe loss of vision (6 or more lines of visual acuity) occurred in 43 treated eyes (53%) and in 33 untreated eyes (40%) at the end of follow-up (range, 12-84 months). A slow and gradual increase of the disciform lesion was demonstrated on fluorescein angiography in 60 untreated eyes, with subfoveal involvement noted in 39 eyes at the end of follow-up. In the treated group, subfoveal involvement occurred in 53 eyes, after a relatively short time (mean, 4 months). Only 28 of the 81 treated eyes had successful anatomic results. These findings suggested that laser treatment of occult neovascularization immediately after the onset of symptoms should not be recommended.

Aged↗
PubMed1990

Anacystis mutants with different tolerances to DCMU-type herbicides show differences in architecture and dynamics of the photosynthetic apparatus, depending on site and mode of the amino acid exchanges in the D 1 protein.

Mutants of Anacystis R 2 with different amino acid exchanges in positions 255 and/or 264 in copy I of the psbA gene, leading to different tolerances to DCMU-type herbicides, are compared with the respective wild type concerning pigmentation and incorporation of 35S into the D 1 protein upon growth in the presence of [35S]methionine. All mutants have shade-type appearance compared to the wild type, although to different extents depending on site and mode of the amino acid exchange in the D 1 protein. Except for 3 mutants, there is no correlation between shade-type appearance on one hand and resistance towards a certain inhibitor on the other hand. Not only the molar ratio of phycocyanin (PC) to chlorophyll (Chl) is higher in all mutants compared to the respective wild type, but also the rate of synthesis of the D 1 protein. On the background of different levels of total 35S incorporation within 18 min, D 1 synthesis can be related to shade adaptation. Degradation of the D 1 protein remains to be thoroughly studied in this context. No reproducible differences in whole chain electron transport were observed between mutants and wild type.

Amino Acid Sequence↗
PubMed1990

[Scanning laser ophthalmoscopy. Its value in macular diseases].

The scanning laser ophthalmoscope provided a high quality television image of the fundus with minimal illumination of the retina. This new device based on a totally new electro-optical principle allowed a detailed exploration of macular function directly under simultaneous fundus control. The focused beam of a yellow krypton laser (568,2 nm) was swept up and down, rights and links across the fundus to form a raster of parallel lines on the retina. The S.L.O. illuminated only a single retinal point at a time and illumination was reduced to less than 70 microw/cm2 versus 100,000 microns/cm2 for indirect ophthalmoscopy and 4,000,000 microw/cm2 for fluorescein angiography. The intensity of the laser beam could be modified with the microcomputer by means of an acousto-optic modulator. It was possible to produce static or dynamic graphic designs that were simultaneously viewed by the patient and observed by the examiner on the patient's fundus on the video monitor. Further computerized analysis of the videotaped scanning laser ophthalmoscopic images gave a functional retinal map with correction for shifts of stimulus position due to fixational saccadic eye movements. The map showed true retinal location of 1. fixation area; 2. scotoma. The clinical evaluation was completed with 3. measurement of visual acuity in any foveal or parafoveal location. The results of scanning laser ophthalmoscopy were illustrated with the report of datas in a patient with diffuse retinal pigment epithelial decompensation.

Adult↗
PubMed1989

[Eye manifestations of Horton's disease].

Ocular complications occurring in temporal arteritis are of different severities. These manifestations of the disease occurred in a population of 57 patients with diagnosis of temporal arteritis, in 16 of them (28%). The diagnosis was suggested by finding an inflammatory syndrome (high erythrocyte sedimentation rate) and confirmed by temporal artery biopsy. In making this diagnosis, it was helpful to find a history of characteristic temporal headaches, neckache, jaw claudication, fever and malaise or weight loss in addition to polymyalgia and polyarthralgia. 6 patients presented with diplopia and different ocular muscle or nerve palsies. The 10 others came for sudden loss of vision due to ischemic anterior or posterior neuropathy and in one case, central artery obliteration. Prompt treatment with steroids gave good results on oculomotor troubles and in preventing the risk of involvement of the fellow eye. But loss of vision did not regress with this treatment. That means the importance in making this diagnosis and starting very promptly this treatment.

Blepharoptosis↗
PubMed1989

[Retinal pigment epithelial tears after photocoagulation in age-related macular degeneration].

Retinal pigment epithelial tears after photocoagulation for subretinal new-vessels complicating age related macular degeneration were observed in 20 patients between 1980 and 1988. The patients, 4 males and 16 females, aged from 60 to 86 years (mean: 72.5) were followed up between 12 and 53 months (mean: 21 months). Laser photocoagulation was performed for directly visible lacy subretinal new-vessels (6 cases) or vascularized pigment epithelial detachment (10 cases) or both lesions associated (4 cases). Krypton laser (17 cases), blue-green argon laser and/or orange dye laser (625 nm) (3 cases) were applied in one (9 cases) to four sessions. Retreatment (11 cases) was performed for persistent subretinal new-vessels (3 cases) or recurrences (4 cases) or appearance of a pigment epithelial detachment after photocoagulation for isolated SRNV (4 cases). The tear was observed on fluorescein angiography 10 to 180 days after the last session. It was preceded by occurrence of subretinal hemorrhages, increase in size of the PED or newly formed PED. It appeared on the border of the PED (16 cases) usually temporally, or on the immediate border of the laser scar (4 cases). Further evolution was rapidly defavorable with dramatic impairment of vision and constitution of fibrovascular scar in the macular area. Only 4 eyes progressed to flat atrophic scars after retreatment and retained useful central vision (0.1 to 0.2). Factors which could explain this complication following laser treatment of age related macular degeneration are discussed.

Aged↗