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At least 973 records · Page 54Linked to original sources
PubMed1987

The kinetics of reduction of yeast complex III by a substrate analog.

The kinetics of reduction of the cytochrome and quinone constituents of yeast complex III by the substrate homolog Q1H2 have been measured under a variety of conditions. The maximum rates of reduction of cytochromes b and c1 and of the endogenous Q6 by Q1H2 were sufficiently fast to support the Vmax for the reduction of cytochrome c by this substrate. The absorbance at 562 nm showed an initial increase which was subsequently followed by a decrease. This decrease was synchronous with the appearance of reduced cytochrome c1 and is interpreted as reflecting the absorbance contribution of c1 at 562 nm under conditions where the steady state level of the b cytochromes is constant. Prereduction of c1 and the Fe/S cluster did not affect the initial very rapid reduction of b, but the second phase was eliminated. Antimycin abolished the very rapid rate of reduction of cytochrome b in untreated complex III and completely inhibited the reduction of cytochrome b in complex III in which c1 and the Fe/S cluster had been prereduced. However, the reduction of the endogenous quinone was essentially unaffected by these treatments. Antimycin had no effect on the reduction of c1. Funiculosin also suppressed the very rapid reduction of b while both myxothiazol and 5-n-undecyl-6-hydroxy-4,7-dioxobenzothiazole did not modify this phase of the reaction; no secondary decrease in absorbance was observed in the presence of any of these inhibitors. Most of the observed kinetic changes could be reproduced by simulation of the Q-cycle; simple linear and branched schemes were unable to reproduce the data.

Electron Transport↗
PubMed1987

[Process control in large-scale technical meat production--poultry].

1. The technical process of poultry meat production influences the quantitative and qualitative bacteriological status of the food broiler-meat in a characteristic and especially explicable manner. 2. Successful provisions to improve the bacteriological status of deep-frozen broiler-meat have to be enforced in the earlier stages of poultry meat production. 3. Controlling the bacteriological status of a product by recourse to the gaining technology is a bearing concept as for self-control-aspects as for official supervision. 4. Nevertheless, to guarantee the comparison of data, a reproducible and as simple as possible bacteriological technique is necessary, which can be commonly accepted and which covers a broad spectrum of bacteria.

Animals↗
PubMed1977

[Use of automatic picture processing in clinical-morphological diagnostics].

The use of the automatic elaboration of pictures for the evaluation of microscopic pictures gives the possibility to automise histological and cytological routine examinations and to improve the recognition of morphological findings by quantitative investigations in the medical morphological diagnostics. The effective practical use of the method is bound to certain device-technical prerequisites which are mentioned in short. At the same time a survey of the principal possibilities in the medical morphological diagnostics is given. By the analysis of the digitalised pictures of cells, cell organelles and other tissue structures reproducible quantitative data on outline and texture as well as on the special arrangement of the objects present in the picture are obtained. On the basis of these characteristics it is possible to identify cells, to find perhaps existing subgroupings in cell populations or to perform an automatic preselection of the material to be investigated. At the instance of the normal white differential blood picture the modern possibilities and limits of the method are described.

Blood Cells↗
PubMed1986

[Improved reproducibility of contrast echocardiography by SH U 454. Experimental studies using digital subtraction echocardiography].

The right heart chambers of 10 animals were contrasted by conventional (NaCl, CO2, H2O2, indocyanine green (ICG), haemaccel) and a newly developed echo-contrast medium (SH U 454) and studied by 2-D echocardiography. By means of digital subtraction echocardiography (DSE) endocardial borders were defined automatically and the results were compared with the manual input of endocardial borders of original and contrast echocardiograms. The area enclosed by these borders served as basis for the calculation of reproducibility (in %) and correlations. The following correlation coefficients (r) and SEE were calculated between the areas defined by the different contrast media and DSE and manually derived borders: r = 0.85, 3.98 cm2 (ICG), and 0.89, 1.00 cm2 (haemaccel). The best calculations were found using SH U 454 in concentrations between 100 and 300 mg/ml. The correlation coefficients were in the range of r = 0.95 and 0.98 with an SEE of 0.21 to 0.56 cm2 between manually and automatically derived contours. Comparing the reproducibility of data between the different evaluation methods we found the following results: manual input of endocardial borders in original echocardiograms 12.3%-16.9%; manual definition of endocardial borders in contrast echocardiograms 2.0% (SH U 454) - 15.7% (CO2); automatic contour finding in original echocardiograms 8.6%-28.9% (mean 21.6%); automatic definition of endocardium by DSE in contrast echocardiograms 7.6% (ICG) - 0.9% (SH U 454, 300 mg/ml). Our results demonstrate that digital subtraction echocardiography is a simple an safe procedure to define endocardial contours if echo contrast media lead to a uniform and homogeneous opacification of the left and right cardiac cavities.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

[Clinical significance of histologic mastopathy diagnosis using quantitative procedures].

Examinations were applied to 101 patients with simple fibrocystic mastopathy (15 cases), proliferative mastopathy (52 cases), invasive ductal carcinoma in concomitance with mastopathy (21 cases), and normal mammary glands (13 probands) in a prospective clinico-morphological pilot study. The use of Robotron A 6471/AMBA-R, a system for automated microscopic image analysis, together with improved methods, has opened up new possibilities for early detection of precancerous changes of the mammary gland. Significant differences were identified between the two clinically relevant groups, II and III, of proliferative mastopathy by quantitative analysis of ductal epithelial proliferations through reproducible measuring data were obtained together with highly distinctive karyometric and histometric parameters. Multiparametrical analysis also provided suggestions to the effect that cases of proliferative mastopathy III, probably, break down into two groups with presumedly differentiated carcinoma risks. Hence, it may well be possible that the biological importance of atypical ductal epithelial proliferations differs from case to case.

Adult↗
PubMed1985

[Automatic contour detection in the 2-dimensional echocardiogram--studies in a general patient population].

In order to test the application of an endocardial contour finding algorithm in apical projections we examined 56 consecutive patients by 2-D echocardiography. According to the quality of the endocardial definition we graded the total patient population in 4 qualities, grade I being the best and grade IV being the worst echocardiographic image with multiple extracavitary and intracavitary artefacts. Following manual and automatic detection of LV endocardium in end-systole and end-diastole by 2 observers we calculated LV areas (cm2), volumes (ml), ejection fraction (%) and regional wall motion (% radial shortening and % area shrinkage) and determined the reproducibility of the two different endocardial definitions. In all echocardiograms with good endocardial visualisation (grade I and II; n = 31, 55%), in 9 out of 15 patients with grade III and 4 out of 10 patients with grade IV echocardiograms we could successfully apply the contour finding algorithm. The comparison between automatically and manually detected contours showed good correlations with small standard errors; however the reproducibility of data expressed by the interobserver variability (V) calculated on the basis of automatically found contours was significantly better as compared to the manually derived contours. (V manual contour = 4.8-8.5 versus automatic contours 0.63-0.68). The systolic volumes (manual versus auto) correlated with r = 0.93, SEE 8.3 ml; the end-diastolic volumes (manual versus auto) with r = 0.90, SEE 11.3 ml, the ejection fraction (manual versus auto) with r = 0.93, SEE 5.1%. The determination of regional LV wall motion demonstrated an agreement in 91% and a discrepancy in 9% of regions.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Output↗
PubMed1979

Reproducibility of the response to diluent challenge in adult asthma.

The authors have demonstrated that patients with bronchial asthma may react to diluent provocative challenge. The pattern of airway response to diluent was found to be reproducible. The data herewith presented suggest that the baseline airway obstruction in adult asthma is highly variable but the degree of baseline obstruction is not related to the response to diluent challenge.

Administration, Intranasal↗
PubMed1983

Quantitative analysis of inorganic particulate burden in situ in tissue sections.

Quantitative information on tissue particulate burden is essential for investigation of relationships of particulates to several aspects of disease, such as exposure, physiology, radiology and pathology. We have developed a method for quantitative analysis of inorganic particulate burden in situ in tissue sections using scanning electron microscopy (SEM) with backscattered electron (BSE) imaging and energy dispersive x-ray analysis (EDXA) or the ion microprobe mass analyzer (IMMA). Our data show reproducible results for concentrations above 10(6) particles per cm3 of tissue. Samples of less than one microgram can be analyzed. Standard 5 microns paraffin sections of formalin fixed tissue are mounted on carbon discs, deparaffinized and examined in the SEM under standardized conditions. Fields of view comprising 10,000 microns3 are searched and all particles visible in the BSE image are counted and individually analyzed by EDXA. Location, number, size and types of particles are tabulated. Previous work showed correlation of quantitative SEM/EDXA with bulk analysis for Ni (r = 0.64), and IMMA with bulk analysis for Be (r = 0.999). Analytical results on exogenous and endogenous particles in 40 lungs (greater than 6000 fields searched and greater than 5700 particles analyzed), and the pathology observed in the tissue, may serve as baseline for future studies on all types of inorganic particles in normal and abnormal lungs. Observed concentrations ranged from 3 X 10(6) to 2 X 10(9) exogenous particles per cm3 of tissue.

Asbestosis↗
PubMedDate not supplied

In vivo quantitation of regional cerebral blood flow in glioma and cerebral infarction: validation of the HIPDm-SPECT method.

Iodine-123 labeled hydroxyiodopropyldiamine (HIPDm) is a diffusible indicator with an 85%-90% extraction fraction and stable retention in the brain for more than 2 hr. Equilibrium-phase imaging and quantitation using single-photon emission computed tomographic (SPECT) scanning defined a distribution of HIPDm in proportion to regional cerebral blood flow (rCBF). Studies in calves affirmed a close correspondence (r = 0.97) in calculated rCBF between HIPDm and microspheres using the tissue deposition-arterial input function microsphere methodology. Using this same mathematical analysis in vivo, reproducible rCBF data within the expected range of normal were obtained on repeated studies in the same nonhuman primate. With a diffuse encephalopathy secondary to subarachnoid blood, a bilaterally symmetric decrease in rCBF was present. A prominent focal decrease in HIPDm accumulation and calculated rCBF was noted with cerebral infarction in the distribution of a ligated middle cerebral artery. Patient studies with glioma revealed diminished HIPDm accumulation due to decreased flow and/or pH in the region of the neoplasm as well as in the associated vasogenic edema and overlying gray matter.

Animals↗
PubMed1982

Determination and calibration of crystal lattice images of biological apatites.

Lattice imaging provides detailed information on the mineral phase of calcified tissues. The lattice space distances dhk1 depend directly on the accuracy of the magnification. Using synthetic apatite, K2PtCl6, graphitized C and crocidolite as calibration material the lattice parameters of human enamel have been determined. The relative errors in the mineral dhk1 values using crocidolite, K2PtCl6 and C are 0.6, 1.0 and 3.9 % resp. If hydroxyapatite is employed on the same grid as the enamel specimen, the d-values obtained are very close to the X-ray diffraction data; a reproducibility of 0.8% in a and c lattice parameter determination can be obtained on selected crystallites.

Crystallography↗
PubMed1993

Transmembrane segment prediction from protein sequence data.

We consider the automated identification of transmembrane domains in membrane protein sequences. 324 proteins (containing 1585 segments) were examined, representing every protein in the PIR database having the transmembrane domain feature annotation. Machine learning techniques were used to evaluate the efficacy of alternative hydrophobicity measures and windowing techniques. We describe a simpler measure of hydrophobicity and a new variable window size concept. We demonstrate that these techniques are superior to some previous techniques in minimizing the segment error rate. Using these new techniques, we describe an algorithm that has a 7.9% segment error rate on the sampled proteins, while classifying 16.7% of the amino acid residues as transmembrane.

Algorithms↗
PubMed1979

[Simultaneous determination of antiepileptic drugs in clinical laboratories: Problems of quality control and standardization (author's transl)].

Methods for determination of antiepileptic drugs in clinical laboratories are discussed with respect to precision, constant error control and economy. Experimental data for reproducibility and standardization are presented for gas chromatographic and photometric methods. Methods for choosing the most suitable procedure for any of the common analytical tasks that may arise in the clinical laboratory are recommended.

Anticonvulsants↗
PubMed1994

[Comparative in vitro dissolution studies of piroxicam suppositories using the basket, the paddle and the flow through methods].

The purpose of our work was the studying of the in vitro dissolution behavior of suppositories containing piroxicam as active ingredient with the Flow-through method comparing the results with the ones obtained by the conventional stirred vessel-USP Paddle and Basket methods. The results indicate that the Flow-through method seems to be useful for studying the dissolution process of suppositories containing piroxicam giving reproducible dissolution data. The Flow-through cell method gives faster in vitro dissolution rates for piroxicam than those with the USP Paddle method, probably caused by steeper concentration gradient at the vicinity of the suppositories as well as better ability to uniformly wet them. The USP Basket method was found to give substantially slower dissolution rates than the other two methods.

Kinetics↗
PubMed1994

Radiographic assessment of bony contributions to knee deformity.

Our recommendations for standing radiography of the lower limb are that assessments be standardized with respect to limb rotation and fixed relative positions of the hip, knee, and ankle. Specifically, a neutral knee rotation position should be set up, defined as alignment of the flexion plane straight ahead. For a complete appraisal, there should be both AP and lateral views in which the positioning of the patient is the same in all respects. The QPR frame greatly assists in achieving these objectives. Furthermore, the presence of a calibration system adds to the reliability and reproducibility of data by compensating for errors of position or alignment arising from the placement of the source and the film. Standardization of positioning also improves the detectability of axial-rotational deformities on comparison of AP and lateral views, providing more reliable indications of the need for CT than possible with nonstandardized short views. When a skyline patellar radiograph is added to the QPR routine, the end result is an excellent appraisal of lower limb alignment, providing a solid basis for diagnosis and planning of appropriate surgical remedies.

Adolescent↗
PubMed1994

Treatment of in-transit metastases from cutaneous melanoma by isolation perfusion with tumour necrosis factor-alpha (TNF-alpha), melphalan and interferon-gamma (IFN-gamma). Dose-finding experience at the National Cancer Institute of Milan.

From December 1991 to July 1993, 22 consecutive patients with grade IIIA-IIIAB melanoma underwent isolation perfusion with TNF-alpha (0.5-4 mg), melphalan (10 mg/l perfused limb) and, in the first 12 cases, IFN-gamma (1.5 x 10(6) U). The first series of 12 patients received a total dosage TNF-alpha of 2-4 mg, and the second series of 10 cases received an escalating dosage of TNF-alpha (1.5-1.0-0.5 mg) and no IFN-gamma before or during surgery. The perfusion lasted 90 min and was conducted in mild hyperthermia (39-39.5 degree C muscle temperature). The results of the first series included seven patients in complete remission, four with stable disease and one case not evaluable for local toxicity. Fifty per cent of cases developed a regional relapse from 3 to 4 months after surgery. Presently with a median follow up of 10 months, five patients of this group have no evidence of disease, four are alive with disease, two died from melanoma and one died of complications likely due to treatment (multi-organ failure syndrome). In the second series, the immediate responses included seven patients in complete remission and three in partial remission; with a median follow up of 3 months, two patients developed a regional relapse, respectively, 3 and 5 months after surgery. So far our experience of perfusion with TNF-alpha has not reproduced the data reported by other investigators. Further clinical and biological findings and a longer follow-up period are needed to draw any conclusion, and a decreasing TNF-alpha dose should be carefully evaluated.

Adult↗
PubMed1993

Automated DNA sequencing: an image processing approach.

An automatic DNA sequencing analysis system has been developed by Scanalytics/CSPI. The strategies used to solve some of the common problems in the automation of DNA sequencing systems will be discussed. Algorithms developed include fast image background correction, automatic base detection, resolution enhancement by deconvolution, desmiling and artificial intelligence algorithms for sequence interpretation.

Algorithms↗
PubMed1993

[Indications, technique and interpretation of arterial Doppler ultrasound].

Doppler sonography is one of the most important diagnostic tools for angiologists and vascular surgeons, and also for general practitioners with an interest in vascular disease. It can be carried out easily and at low cost and at the same time provides reproducible, quantitative data on with further diagnostic and therapeutic decisions can be based. First, systolic arterial pressure in the anterior and posterior tibial and in the peroneal arteries are measured, with the Doppler probe placed at ankle level. A cuff is wrapped around the lower leg and inflated until the Doppler signal disappears and then deflated. The highest value measured in each leg is termed "ankle pressure". Division of the latter by systolic brachial pressure results in the so-called "ankle-brachial-index" or "ABI". Ankle pressure and ABI correlate well with clinical findings. In normal individuals, the ABI is greater than 1. In claudicators, it ranges between 0.3 and 0.9, in patients with resting pain between 0.1 and 0.5 and with ischemic tissue loss between 0.0 and 0.2. After angioplastic or surgical revascularisation procedures, a fall of the ABI by 0.15 or more is an indication of relevant hemodynamic deterioration and therefore calls for further investigation by arteriography or colour duplex sonography.

Arterial Occlusive Diseases↗