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Santorio Sanctorius (1561-1636) - founding father of metabolic balance studies.

The intellectual renaissance of the closing decades of the sixteenth century provided the fertile ground in which the budding spirit of scientific inquiry emerged in the seventeenth century. Direct observation, soon augmented by instrumentation that allowed for quantification and, therefore, verification, became the revelatory medium for the progress of the sciences. In medicine, progress depended on the application of the exact sciences of chemistry, mathematics and physics to the study of function. One of the medical luminaries of this early scientific revolution was Santorio Sanctorius (1561- 1636), whose principal contributions were his studies on insensible perspiration and his instrumental inventions. To study insensible perspiration, he designed a movable platform attached to a steelyard scale that allowed for the quantification of changes in body weight of subjects who partook in their daily activities on the platform. After years of self-experimentation, he applied his device to the study of patients. Unfortunately, his records are lost. What survives is a summary of his observations in a series of aphorisms published under the title of Ars de statica medicina, in 1614; 3 years after he was appointed Ordinary Professor of Theoretical Medicine in Padua. To enhance the bedside evaluation of patients, he also designed instruments to quantify the pulse, temperature, and environmental humidity. For his pioneering and detailed balance studies, Sanctorius clearly deserves the title of founding father of metabolic balance studies.

Equipment and Supplies↗

Nonlinear hearing AIDS and verification of fitting targets.

This paper addresses the issue of initial verification of hearing aid gain and output for nonlinear hearing aids. Specifically, "urban legend" has it that nonlinear hearing aids with digital noise reduction circuitry may not be accurately measured using functional gain and/or probe microphone measures. Discussed are the advantages and disadvantages of both measurement strategies, and how they may be used to "acoustically match" hearing aids to individual patients. An evaluation protocol that employs both optimal aided thresholds and probe microphone measurements to assess gain, output, and audibility in hearing-impaired patients.

Journal Article↗

[Biomathematical aspects of numerical evaluation and mathematical modelling of non-monotonous exponential measuring processes].

Measurements of endocrinological and pharmacological processes often yield courses of time series with exponentially saturated increasing first part followed by an exponentially decreasing part. Such measured courses may be mathematically modelled by the so-called BATEMAN function type, an expression consisting of 2 e-function terms. In this paper, the method of locally adjusted functional approximation for model-free quantitative evaluation of measured time series is sketched. By means of 2 real examples of measured data, it will be demonstrated how the results of the model-free evaluation may serve for internal regression to estimate starting parameter values for an iterative fitting of a BATEMAN function to measured data courses. Furthermore, it is shown that the model-free approach of data evaluation may give substantial hints for the mathematical model building process and for model verification.

Animals↗

Gene stability in mammalian cells and protein consistency.

The safety of a patient who is the recipient of protein drugs has to be assured. A "wrong" protein is thought to represent a great risk. The philosophy of testing strategies related to gene stability with product safety will be discussed in the light of experimental data available today. Although all mammalian cell lines used in the production of biologicals including recombinant DNA-derived lines have been produced from individual clones (functional monoclonality) they have been found to be heterogenous with regard to the genomic content (number of chromosomes, characteristics of identifiable chromosomes and position and number of integrated recombinant sequences). The verification of the presence of correct gene in a production cell line constitutes a well accepted and useful test, especially if derived by "population sequencing". A batch not related repeated confirmation of this fact cannot lead to any additional assurance for the correctness of all proteins constituting a given product beyond the level provided by cheminal testing. In contrast to this obvious and unavoidable heterogeneity in cellular genomes, the coding regions of genes have not been shown to change. Evidence is available to demonstrate the consistency of protein products originating from recombinant (and hybridoma) cell lines, e.g. more than 500,000 patients have received and tolerated rtPA well.

Aneuploidy↗

[Relationship of closing volume to other lung function tests].

The closing volume method is suitably to be used in exposed groups of the population, the preliminary diagnostics of them is inconspicuous, in order to establish in time beginning and thus therapeutically influencible alterations of the small respiratory tract. In such a group of test persons only relatively slight connections with the other conventional lung standard methods are the result, by means of which its independence is emphasized. On the other hand less promising seems to be the application of the method in the verification of a "small airways obstruction" in smokers, whose vital capacity, forced expiratory volume and residual volume are within the normal.

Adult↗

Distribution and partial characterization of seasonally expressed proteins in different aged shoots and roots of 'Loring' peach (Prunus persica).

During autumnal leaf senescence, leaf nitrogen in deciduous trees is translocated to storage sites, especially bark and xylem tissues. Proteins that accumulate in large amounts in bark and xylem in winter and are absent from these organs in summer are called storage proteins, and are believed to be vehicles for storing nitrogen reserves. These reserves are important for spring growth and help trees tolerate or recover from both abiotic and biotic stresses. Based on seasonal patterns of accumulation, we previously identified three storage proteins with molecular masses of 60, 19 and 16 kDa in bark tissues of 'Loring' peach (Prunus persica (L.) Batsch). To characterize the distribution of these proteins in different-aged tissues and to determine if they have any function other than nitrogen storage, we examined their seasonal distribution in bark tissues of current-year and 1-year-old shoots, scaffold branches, main trunks and 4-5-year-old roots of 'Loring' peach. Verification of protein identity was based on molecular mass and reactions with antibodies directed against each specific protein. Protein distribution was variable. For all three proteins, the greatest amount was present in mid-winter in current-year and 1-year-old shoots. These tissues also showed the greatest seasonal variation in the amount of protein present. The 16 kDa protein was present only in the youngest shoots, whereas the 19 kDa protein was present in all tissues examined. The 60 kDa protein was absent in root tissue. The amino acid composition and sequence of each protein were determined. The 60 kDa protein was identified as a dehydrin, and the 19 kDa protein appeared to be related to a family of allergen proteins in Rosaceous plants, some members of which are associated with pathogenesis-related proteins. The amino acid sequence of the 16 kDa protein appeared to have no homology with any proteins in the SwissProt database. Therefore, it is likely that the 16 kDa protein, in a strict sense, is a bark storage protein. Defining storage proteins solely by their pattern of accumulation and the extent to which they accumulate may not be a good functional definition. It is possible that storage proteins have functional roles in addition to nitrogen storage.

Electrophoresis, Polyacrylamide Gel↗

Dynamics of local conformation and enzyme function.

Enzyme function is critically affected by gross changes in tertiary structure, but much less is known about the dependence of activity on localized conformational changes that might occur during the catalytic process. Such information is essential to the understanding and verification of enzyme mechanisms, and can only be obtained from systems in which the substrate binding and catalytic groups of the enzyme active centre are not only identified but also rendered appropriate probes of the catalytic reaction, that is they must signal changes in their mutual interactions at rates at least as fast as catalysis. It should then be possible to observe directly each of the dynamic events that result in catalysis. Time-averaged structural analyses can neither reveal the dynamics of catalysis nor describe the conformational details of molecules who structures-particularly of the active centre-are motile. Moreover, the three-dimensional structures of enzymes in crystals and solutions may not always be identical as evidenced by marked differences between the kinetic properties of crystalline and of dissolved enzymes (e.g. hexokinase, glycogen phosphorylase and carboxypeptidases A and B). Various experimental approaches have been devised to explore the relationship between structure and function of these and other enzymes. We have focused on the syncatalytic, spatial relationships of active-site residues as they bear on the mechanism of enzyme action using absorption, circular dichroism, magnetocircular dichroic, and resonance Raman spectroscopy as well as resonance energy transfer. Stopped-flow, pH and temperature jump methods quantitatively assess both the conformational and local structural features of the enzyme and reveal multiple, discrete conformational states that prove to have mechanistic significance. These and related data serve as a basis for a minimal model of the dynamic aspects of enzyme action.

Binding Sites↗

Four different mutations in codon 28 of alpha spectrin are associated with structurally and functionally abnormal spectrin alpha I/74 in hereditary elliptocytosis.

Hereditary elliptocytosis (HE) Sp alpha I/74 is a disorder associated with defective spectrin (Sp) heterodimer self-association and an abnormal tryptic cleavage of the 80-kD alpha I domain of Sp resulting in increased amounts of a 74-kD peptide. The molecular basis of this disorder is heterogeneous and mutations in codons 28, 46, 48, and 49 (codons 22, 40, 42, and 43 in the previous nomenclature which did not include the six NH2-terminal amino acids) have been reported. In this study we present data on seven unrelated HE Sp alpha I/74 kindred from diverse racial backgrounds in whom we identified four different mutations all occurring in exon 2 of alpha Sp at codon 28. Utilizing the polymerase chain reaction we established a CGT----CTT; Arg----Leu 28 mutation in one kindred of Arab/Druze origin. In two unrelated white kindred of English/European origin the substitution is CGT----AGT; Arg----Ser 28 and in two apparently unrelated white kindred from New Zealand, the mutation is CGT----TGT; Arg----Cys 28. Finally, in one American black kindred and in a black kindred from Ghana the mutation involves CGT----CAT; Arg----His 28. Allele specific oligonucleotide hybridization confirmed that the probands are heterozygous for the respective mutant alleles. All four point mutations abolished an Aha II restriction enzyme site which allowed verification of linkage of the mutation with HE Sp alpha I/74. Our results imply that codon 28 of alpha Sp is a "hot spot" for mutations and also indicate that Arg 28 is critical for the conformational stability and functional self association of Sp heterodimers.

Base Sequence↗

Megavoltage CT on a tomotherapy system.

A megavoltage computed tomography (MVCT) system was developed on the University of Wisconsin tomotherapy benchtop. This system can operate either axially or helically, and collect transmission data without any bounds on delivered dose. Scan times as low as 12 s per slice are possible, and scans were run with linac output rates of 100 MU min(-1), although the system can be tuned to deliver arbitrarily low dose rates. Images were reconstructed with clinically reasonable doses ranging from 8 to 12 cGy. These images delineate contrasts below 2% and resolutions of 3.0 mm. Thus, the MVCT image quality of this system should be sufficient for verifying the patient's position and anatomy prior to radiotherapy. Additionally, synthetic data were used to test the potential for improved MVCT contrast using maximum-likelihood (ML) reconstruction. Specifically, the maximum-likelihood expectation-maximization (ML-EM) algorithm and a transmission ML algorithm were compared with filtered backprojection (FBP). It was found that for expected clinical MVCT doses enough imaging photons are used such that little benefit is conferred by the improved noise model of ML algorithms. For significantly lower doses, some quantitative improvement is achieved through ML reconstruction. Nonetheless, the image quality at those lower doses is not satisfactory for radiotherapy verification.

Algorithms↗

[An attempt to use simplified mathematical analysis for evaluation of elimination of cyclobarbital from blood of acutely poisoned patients].

Two different mathematical methods were used to calculate the rate of poison elimination in 52 unconscious patients due to barbiturate poisoning. The process of poison elimination is reflected by an exponential curve. Its rate can be determined with the use of a logarithmic function formula. In the study, an attempt was made to find out whether a linear function formula could also be applied to calculate this parameter. The hypothesis was based on the observation that, when considered for short periods of time parts on an elimination curve resemble straight line. The barbiturate elimination was checked every four hours to ensure that the exponential curve be as close as possible to a straight line. Then, correlations between the rate of poison elimination calculated from both formulas and seven biochemical and clinical parameters of forced diuresis were examined. The findings revealed qualitative concordance of the results, i.e. correlations were found for the same parameters when the elimination rate was calculated either from the logarithmic or linear formula. For further verification of the hypothesis apart from a simple correlation analysis a normalized standard error (NSE) method was used to investigate these correlations. Also in this analysis a similar concordance of results was obtained: when there was a correlation between the elimination rate as a logarithmic function and particular parameter of forced diuresis, it was also found the same for the rate calculated from the linear function formula. Conversely the absence of correlation in the former case corresponded to similar absence in the latter.(ABSTRACT TRUNCATED AT 250 WORDS)

Barbiturates↗

A proteomic view of Desulfovibrio vulgaris metabolism as determined by liquid chromatography coupled with tandem mass spectrometry.

Direct LC-MS/MS was used to examine the proteins extracted from exponential or stationary phase Desulfovibrio vulgaris cells that had been grown on a minimal medium containing either lactate or formate as the primary carbon source. Across all four growth conditions, 976 gene products were identified with high confidence, which is equal to approximately 28% of all predicted proteins in the D. vulgaris genome. Bioinformatic analysis showed that the proteins identified were distributed among almost all functional classes, with the energy metabolism category containing the greatest number of identified proteins. At least 154 ORFs originally annotated as hypothetical proteins were found to encode the expressed proteins, which provided verification for the authenticity of these hypothetical proteins. Proteomic analysis showed that proteins potentially involved in ATP biosynthesis using the proton gradient across membrane, such as ATPase, alcohol dehydrogenases, heterodisulfide reductases, and [NiFe] hydrogenase (HynAB-1) of the hydrogen cycling were highly expressed in all four growth conditions, suggesting they may be the primary pathways for ATP synthesis in D. vulgaris. Most of the enzymes involved in substrate-level phosphorylation were also detected in all tested conditions. However, no enzyme involved in CO cycling or formate cycling was detected, suggesting that they are not the primary ATP-biosynthesis pathways under the tested conditions. This study provides the first proteomic overview of the cellular metabolism of D. vulgaris. The complete list of proteins identified in this study and their abundances (peptide hits) is provided in Supplementary Table 1.

Alcohol Dehydrogenase↗

An evaluation of video playback using Xiphophorus helleri.

Video playback is being increasingly used as a technique for behavioural research. The importance of critically evaluating the effectiveness of video playback is clear, as available video technology is not designed for nonhuman visual systems. We discuss several aspects concerning the perception of video images that could lead to inconclusive or erroneous results. Researchers should verify that behaviour observed in response to video playback is comparable to behaviour observed in response to live animals. We conducted such a verification using live and video playback methods to measure female response to swords of varying lengths in the green swordtail, Xiphophorus helleri. Using both methods, female response appeared to be an increasing function of male sword length. Females did not differ in their response to live and video versions of noncourting, noninteractive males, however, females tended to prefer video playbacks of males with longer swords, a result that has also been found in experiments using live males. These results suggest that females express the same qualitative mating preference, but not necessarily the same quantitative preference, for sword length when viewing video stimuli. Several methodological factors that may contribute to an apparent difference in the strength of the preference are discussed. Despite these differences, both methods produced comparable results; female response to sworded males tended to increase as sword length increased. These experiments demonstrate that video playback is an effective method to measure female preferences accurately in X. helleri and provide an example of how video playback can be evaluated in other species. Copyright 2000 The Association for the Study of Animal Behaviour.

Journal Article↗

[New aspects of molecular biology diagnosis. Array technology and expression profile for characterization of rheumatic diseases].

Increasing availability of high throughput technologies, exponentially growing information about the human genome and gene expression, and the growing global network of databases on systematic biomedical information will change our view on inflammatory rheumatic diseases in a revolutionary way. Several research laboratories have already generated initial extensive datasets on gene expression analysis. Application of this technique has demonstrated that in addition to a precise analysis, verification and validation of the results also on the level of cell populations, a meticulous characterization of the patients according to current conventional clinical, laboratory, imaging and histological standards is essential. For functional interpretation, in vitro tests, animal models and therapeutic studies will provide further information. Bioinformatic structuring and development is needed for the large amounts of data. After an initial genome-wide screening, the objective is to identify those genes, which will allow characterization of the disease, classification according to molecular pathophysiology, evaluation of the prognosis and prediction of the correct and most potent therapeutic regimen. Derived from the improved knowledge about the molecular mechanisms, new and--as to expect--the crucial approaches for an effective therapy against chronic inflammation, organ destruction and pathological immune response in rheumatic diseases will emerge.

Autoantibodies↗

A multivariate model for predicting mortality in patients with heart failure and systolic dysfunction.

BACKGROUND: Heart failure is a leading cause of morbidity and mortality, but there are no reliable models based on readily available clinical variables to predict outcomes in patients taking angiotensin-converting enzyme (ACE) inhibitors. METHODS: A multivariate statistical model to predict mortality was developed in a random sample (n = 4277 patients [67%]) of the 6422 patients enrolled in the Digitalis Investigation Group trial who had a depressed ejection fraction (<or=45%), were in sinus rhythm, and were taking ACE inhibitors. The model was then validated in the remaining 2145 patients. RESULTS: Total mortality in the derivation sample was 11.2% (n = 480) at 12 months and 29.9% (n = 1277) at 36 months. Lower ejection fraction, worse renal function, cardiomegaly, worse functional class, signs or symptoms of heart failure, lower blood pressure, and lower body mass index were associated with reduced 12-month survival. This model provided good predictions of mortality in the verification sample. The same variables, along with age and the baseline use of nitrates, were also predictive of 36-month mortality. CONCLUSION: Routine clinical variables can be used to predict short- and long-term mortality in patients with heart failure and systolic dysfunction who are treated with ACE inhibitors.

Aged↗

Scale-up of chromatographic ion-exchange processes in biotechnology.

The van Deemter equation has been used to derive a rule of thumb guideline for scaling. The scaling is done by the concept of time scales. The time scales are kept identical for all the columns by scaling the flow rate to the total void volume and the load to the amount of the media. The verification of theoretical background for the linear gradient elution is reported. The results demonstrate that the gradient retention behaviour of protein is independent of the column aspect ratio, but it's a function of the initial salt concentration and the gradient slop G'.

Adsorption↗

Concentration verification of ethanol/nitrogen compressed gas cylinders prior to use for periodic determinations of accuracy in California.

A method that uses compressed gas ethanol breath standard (EBS) cylinders to perform periodic determinations of accuracy on evidential breath alcohol instruments in California was developed. To use EBS cylinders, the California State Department of Health Services required verification of the ethanol content of the EBS cylinders using an infrared method. The infrared method developed employs a modified Alcotest 7110 MK III-C manufactured by National Draeger, Inc. that functions at the 9.5-mm wavelength of the infrared spectrum. Criteria and methodology for verifying EBS cylinder ethanol concentrations are described.

Air Pressure↗

Identification and partial characterization of differentially expressed mRNAs in normal human endometria and endometrial carcinomas by differential display RT-PCR.

Differential display methodology was employed to examine and compare the mRNA species derived from normal endometrial tissue and endometrial carcinoma (grade 3, stage III) tissue biopsies. Two cDNA sequences, one expressed in the tumour group only (T19) and the other expressed only in the normal group (N22), were selected for verification of differential expression by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The expression of N22 was restricted to the normal group, suggesting a possible tumour suppressing function. Sequence analysis of this fragment revealed a high degree of similarity to a human cDNA sequence of unknown function. The expression of T19 mRNA was observed in both normal and neoplastic tissues, however the relative abundance was significantly higher in endometrial carcinomas. Expression of T19 mRNA was further examined in a larger clinical sample set and was significantly increased in the tumours (n = 16), with a three-fold increase when compared with the normal endometria, n = 5 (Kruskal-Wallis analysis of variance, P<0.05). Subsequent sequence analysis of T19 revealed a high degree of similarity to the 3' untranslated region of a rat growth factor responsive gene, SM-20. Further characterization of these mRNA transcripts may lead to the identification of novel genes involved in endometrial tumourogenesis.

3' Untranslated Regions↗

Role of radiation therapy in the management of meningioma.

Surgery is the accepted form of treatment of meningioma; the role of radiotherapy has not been clearly established. With this in mind, we have reviewed our experience with radiation therapy in the management of meningiomas at New York University Medical Center. Sixty-eight patients fell into three groups. Forty-three (Group A) underwent operation followed by radiation therapy, 14 patients (Group B) had radiation for recurrence after operation, and 11 patients (Group C) had radiation therapy as the primary treatment. In Group A, 41 of 43 are alive. During a follow-up of 1 to 10 years, only 2 have deteriorated. Five of 14 Group B patients showed neurological improvement and 7 showed deterioration, including 5 who died of tumor. All 11 patients in Group C are alive with follow-up periods of 3 to 6 years; 9 of these show improvement in neurological function. Eleven patients had malignant meningioma, of whom 8 are alive and stable. We present 4 case reports, including computed tomographic scans that show evidence of tumor necrosis after radiation therapy. Pathological verification of tumor necrosis is presented in 1 case. We believe that radiation therapy has an established role in the treatment of incompletely excised, recurrent, or malignant meningiomas and, in some cases, as the initial management of meningiomas. Indications for treatment and guidelines are presented.

Bone Neoplasms↗