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Results for “Quantitative biology”

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At least 19 recordsLinked to original sources
PubMed2003

FGF-2 stimulation affects calvarial osteoblast biology: quantitative analysis of nine genes important for cranial suture biology by real-time reverse transcription polymerase chain reaction.

Appropriately timed closure of the cranial sutures is a critical factor in normal postnatal morphogenesis of the cranial vault. Suture patency is necessary to permit rapid neonatal expansion of the cerebral hemispheres, and later ossification is important for bony protection of the cerebrum. Premature suture ossification (craniosynostosis) leads to myriad adverse functional and developmental consequences. Several murine studies have implicated dura-derived fibroblast growth factor-2 (FGF-2) paracrine signaling as a critical factor promoting physiologic posterior frontal suture fusion. In this study, the authors used real-time reverse transcription polymerase chain reaction (RT-PCR) to study an in vitro system that models the in vivo stimulation of suture calvarial osteoblasts by dura-derived FGF-2. The authors advocate real-time RT-PCR as a powerful and rapid technique that offers advantages in the highly sensitive, specific, and reproducible analyses of nine genes known to be important in cranial suture biology. The genes studied were growth factors [FGF-2, transforming growth factor (TGF)-beta 1, TGF-beta 2, and TGF-beta 3], growth factor receptors (FGF-R1, FGF-R2, TGF-beta RI, and TGF-beta RII), and a marker of osteoblast differentiation (Co1-I alpha I). These analyses provide a "snapshot" of several important genes involved in suture fusion that is more inclusive and quantitative than that which has been previously reported.

Animals↗
PubMed1994

Quantitative biological electron probe microanalysis with a wavelength dispersive spectrometer.

This paper describes the details of quantitative electron probe microanalysis (EPMA) performed with a wavelength dispersive spectrometer (WDS). EPMA was carried out on the giant neuron of a fresh frozen ganglion from the snail Lymnaea stagnalis. The freeze-dried cryosections were compared with sections of freeze-dried, embedded tissue. It was found, that in the ganglion there are two kinds of neurons with a different chlorine concentration of 11 mmole/liter and 32 mmole/liter. Isolated neurons in culture were shown to differ in elemental composition from those in the ganglion tissue.

Animals↗
PubMed1983

Quantitative biological X-ray microanalysis of bulk specimens: an analysis of inaccuracies involved in ZAF-correction.

In this paper the need for a biological approach to ZAF-correction is elucidated. Programming details are given for the compostion of a ZAF-correction program, specifically designed for biological specimens. BIOFLEX was written and set up as a working program to investigate two specific inaccuracies involved in quantitative X-ray microanalysis of biological bulk specimens: These are the poorly known composition of the organic matrix of the specimen as well as the poorly known specimen-beam spectrometer geometry. The outcome of our calculations, which is based on hypothetical (but representative) data, indicates that the organic matrix composition should be specified in elemental miss fractions. Moreover it was found that a poorly known geometry will give errors in concentrations of about 1 - 2%.

Animals↗
PubMed1982

The significance of quantitative biological cell parameters in the handling of mammary carcinoma.

Recent work has shown that in breast cancer patients DNA measurements and estrogen receptor (ER)- analysis can contribute valuable information in the judgement of prognosis and choice of therapy. We report a case of advanced breast carcinoma with extensive liver metastases which clinically was regarded as beyond all therapeutic possibilities. Liver metastases were diagnosed first. Some time later a breast carcinoma was detected which was suggested to be the primary malignancy. Since high ER-values were demonstrated in the breast carcinoma, anti-estrogen therapy was given on trial. After three months the tumor mass in the liver had drastically diminished and today, more than 4 years after diagnosis, the patient is free from symptoms and doing excellently. A retrospective, microspectrophotometric DNA analysis in both the breast carcinoma and the liver metastasis showed DNA distribution patterns with nearly all the carcinoma cells exhibiting DNA values in the normal diploid region. This type of DNA profile has previously been shown to be correlated with good prognosis. We conclude that quantitative parameters such as DNA- and ER-content can give prognostic and therapeutic information over the above that furnished by clinical stage and morphological criteria.

Adenocarcinoma↗
PubMed1989

Quantitation, biological and physicochemical properties of cell culture-adapted porcine epidemic diarrhea coronavirus (PEDV).

The porcine epidemic coronavirus (PEDV), tentatively classified as a coronavirus, was adapted to Vero cells and a plaque test developed for infectivity titration, allowing us to test the biological and biophysical properties of the virus. Growth kinetics showed peak titers of 10(5.5) plaque-forming units ml-1 15 h after infection. Filtration experiments and electron microscopy revealed a particle diameter between 100 and 200 nm. The buoyant density of the virus was 1.18. The particle lost its infectivity on treatment with lipid solvents. Virus replication could not be inhibited by 5-iodo-2'-deoxyuridine. PEDV was moderately stable at 50 degrees C, but heat sensitivity was not altered by divalent cations. At 4 degrees C, the virus was stable between pH 5.0 and 9.0, but at 37 degrees C stability was restricted to the pH range 6.5-7.5. Viral infectivity was not impaired by ultrasonication or by multiple freezing and thawing. PEDV was not neutralized by transmissible gastroenteritis virus antiserum. On the basis of the tests carried out, PEDV is a pleomorphic, enveloped RNA virus with a particle diameter of approximately 150 nm and a buoyant density of 1.18. Infectivity depends on the presence of trypsin, and infected cells show a tendency to fuse and to form syncytia. All of these properties, as well as its physicochemical characteristics, allow PEDV to be classified as a coronavirus.

Animals↗
PubMed2005

Brachidontes variabilis and Patella sp. as quantitative biological indicators for cadmium, lead and mercury in the Lebanese coastal waters.

The mussel, Brachidontes variabilis, and the limpet, Patella sp., were used as indicators to monitor cadmium, lead and mercury concentrations along the Lebanese coast. Studies were carried out in order to define the best strategy for assessing and minimizing the effects of size and physiological condition on the metal contents of the molluscs, and corrective models were constructed. Metal concentrations in surface water were measured to estimate bioconcentration factors (BCFs). The BCFs varied from 8.3 x 10(3) to 3.4 x 10(4), from 7.5 x 10(3) to 8.0 x 10(3) and from 3.0 x 10(4) to 3.2 x10(4), for Cd, Pb and Hg, respectively. For limpets, BCFs varied from 1.7 x 10(4) to 7.4 x 10(4) for Cd, from 2.5 x 10(3) to 6 x 10(3) for Pb and remained fairly constant at around 10(4) for Hg. The highest BCFs were associated with lowest contamination levels. The results of the geographical survey exhibited a similar large-scale spatial pattern for the two species and followed the metal concentration distributions measured in the waters.

Animals↗
PubMed1999

LXIII Cold Spring Harbor Symposium on Quantitative Biology: Mechanisms of Transcription, 3-8 June 1998.

A new perspective is emerging in the transcription field towards understanding gene regulation not only at its most fundamental level but also in the context of chromatin, nuclear compartmentalization, and physiological processes. This direction is being fueled by several key observations. Among them is the discovery of multi-protein complexes whose components reveal a link between gene activity, nuclear structure, and cellular signaling pathways. This information will no doubt be extended by identifying expanded regulatory circuitry using the microchip oligonucleotide array technology. In addition to elucidating the regulatory consequences of these intricate connections, another frontier will be to analyze gene expression within chromosomes. This requires deciphering the mechanism of action of a variety of DNA elements that create a genetic domain such as locus control regions, distal enhancers, insulators, silencers, and matrix attachment regions. Hopefully, with the development of new assays these elements can be as rigorously defined as promoters have been. We can also look forward to capturing critical transcriptional processes by increasingly refined structural analyses. Thus, the scope of problems being addressed in gene regulation has been greatly expanded and the opportunity exists to answer very sophisticated questions in the future.

Archaea↗
PubMed2005

Towards quantitative biology: integration of biological information to elucidate disease pathways and to guide drug discovery.

Developing a new drug is a tedious and expensive undertaking. The recently developed high-throughput experimental technologies, summarised by the terms genomics, transcriptomics, proteomics and metabolomics provide for the first time ever the means to comprehensively monitor the molecular level of disease processes. The "-omics" technologies facilitate the systematic characterisation of a drug target's physiology, thereby helping to reduce the typically high attrition rates in discovery projects, and improving the overall efficiency of pharmaceutical research processes. Currently, the bottleneck for taking full advantage of the new experimental technologies are the rapidly growing volumes of automatically produced biological data. A lack of scalable database systems and computational tools for target discovery has been recognised as a major hurdle. In this review, an overview will be given on recent progress in computational biology that has an impact on drug discovery applications. The focus will be on novel in silico methods to reconstruct regulatory networks, signalling cascades, and metabolic pathways, with an emphasis on comparative genomics and microarray-based approaches. Promising methods, such as the mathematical simulation of pathway dynamics are discussed in the context of applications in discovery projects. The review concludes by exemplifying concrete data-driven studies in pharmaceutical research that demonstrate the value of integrated computational systems for drug target identification and validation, screening assay development, as well as drug candidate efficacy and toxicity evaluations.

Animals↗
PubMed2004

Viruses and the development of quantitative biological electron microscopy.

The electron microscope has become an important tool for determining the structure of biological materials of all kinds. Many technical advances in specimen preparation and in sophisticated methods of image analysis, initially based on optical systems but latterly on computer processing, have contributed to the development of the subject. Viruses of various kinds have often provided a convenient and appropriate test specimen. This paper describes the major technical advances and shows how viruses have had an important role in most of the developments.

Bacteriophage T4↗