Computerized analysis of fetal heart rate variability using the matching pursuit technique as an indicator of fetal hypoxia during labor.

OBJECTIVE: To determine whether the computerized analysis of fetal heart rate variability with the new matching pursuit technique can indicate fetal distress during labor. STUDY DESIGN: Eighty women were studied during the intrapartum period with external cardiotocography. In all cases, cord arterial pH and 5-min Apgar Scores were evaluated. Six cases that presented large segments of missing data were excluded from the study. The remaining 74 women were divided into two groups; 32 women with normal (Group A) and 42 women with non-reassuring FHR tracings (group B). Group B was divided in subgroup BI, including 24 women with pH > 7.20, and BII, including 18 women with pH < 7.20. In order to evaluate the FHR fluctuations, in different frequency ranges, we applied an adaptive time-frequency method, called Matching Pursuit. We estimated the power of the FHR signal in four frequency ranges. RESULTS: The 5-min Apgar Scores were significantly lower in both subgroup BI and subgroup BII (p = 0.003 and p = 0.003 respectively). The Low Low Frequency (LLF) parameter appears to recognize better the cases with lower pH (sensitivity 78.5%, specificity 52.3%) than the cases with non-reassuring FHR (66.6%, 56.2). The sensitivity and specificity of the Very Low Frequency (VLF) parameter were 72.2% and 59% respectively in recognizing the cases with lower pH and 64.2% and 53.1% in recognizing non-reassuring FHR. CONCLUSION: Fetal hypoxia during labor can be recognized using the MP technique for the analysis of FHR signal power in the VLF and LLF frequency ranges. Since the analysis is feasible in real-time, it can be a useful tool for the intrapartum evaluation of fetal well-being.

Computerised intrapartum diagnosis of fetal hypoxia based on fetal heart rate monitoring and fetal pulse oximetry recordings utilising wavelet analysis and neural networks.

OBJECTIVE: To develop a computerised system that will assist the early diagnosis of fetal hypoxia and to investigate the relationship between the fetal heart rate variability and the fetal pulse oximetry recordings. DESIGN: Retrospective off-line analysis of cardiotocogram and FSpO2 recordings. SETTING: The Maternity Unit of the 2nd Department of Obstetrics and Gynaecology, Aretaieion Hospital, University of Athens. POPULATION: Sixty-one women of more than 37 weeks of gestation were monitored throughout labour. METHODS: Multiresolution wavelet analysis was applied in each 10-minute period of second stage of labour focussing on long term variability changes in different frequency ranges and statistical analysis was performed in the associated 10-minute FSpO2 recordings. Self-organising map neural network was used to categorise the different 10-minute fetal heart rate patterns and the associated 10-minute FSpO2 recordings. MAIN OUTCOME MEASURES: Umbilical artery pH of < or = 7.20 and Apgar score at 5 minutes of < or = 7 formed the inclusion criteria of the risk group. RESULTS: After using k-means clustering algorithm, the two-dimensional output layer of the self-organising map neural network was divided into three distinct clusters. All the cases that mapped in cluster 3 belonged in the risk group except one. The sensitivity of the system was 83.3% and the specificity 97.9% for the detection of risk group cases. CONCLUSIONS: A relationship between the fetal heart rate variability in different frequency ranges and the time in which FSpO2 is less than 30% was noticed. Fetal pulse oximetry seems to be an important additional source of information. Computerised analysis of the fetal heart rate monitoring and pulse oximetry recordings is a promising technique in objective intrapartum diagnosis of fetal hypoxia. Further evaluation of this technique is mandatory to evaluate its efficacy and reliability in interpreting fetal heart rate recordings.

Enhanced proliferation and differentiation of human articular chondrocytes when seeded at low cell densities in alginate in vitro.

Dedifferentiated human articular chondrocytes exhibited a wide variation in their capacity to proliferate and redifferentiate in an alginate suspension culture system. The greatest extent of proliferation and redifferentiation was seen to be dependent on the formation of clonal populations of chondrocytes and correlated inversely with the initial cell seeding density. Redifferentiating chondrocytes seeded at low density (1 x 10(4) cells/ml alginate) compared with chondrocytes that were seeded at high density (1 x 10(6) cells/ml alginate) showed a nearly 3-fold higher median increase in cell number. a 19-fold greater level of type-II collagen mRNA expression, a 4-fold greater level of aggrecan mRNA expression, and a 6-fold greater level of sulfated glycosaminoglycan deposition at 4 weeks of culture. Matrix molecules from low-density cultures were assembled into chondrocyte-encapsulated, spherical extracellular matrices that were readily visualized in sections from 12-week cultures stained with antibodies against types I and II collagen and aggrecan. Ultrastructural analysis of 12-week low-density cultures confirmed the presence of thin collagen fibrils throughout the matrix.

Endostatin: an endogenous inhibitor of angiogenesis and tumor growth.

We previously identified the angiogenesis inhibitor angiostatin. Using a similar strategy, we have identified endostatin, an angiogenesis inhibitor produced by hemangioendothelioma. Endostatin is a 20 kDa C-terminal fragment of collagen XVIII. Endostatin specifically inhibits endothelial proliferation and potently inhibits angiogenesis and tumor growth. By a novel method of sustained release, E. coli-derived endostatin was administered as a nonrefolded suspension. Primary tumors were regressed to dormant microscopic lesions. Immunohistochemistry revealed blocked angiogenesis accompanied by high proliferation balanced by apoptosis in tumor cells. There was no toxicity. Together with angiostatin data, these findings validate a strategy for identifying endogenous angiogenesis inhibitors, suggest a theme of fragments of proteins as angiogenesis inhibitors, and demonstrate dormancy therapy.

The late retinoic acid induction of laminin B1 gene transcription involves RAR binding to the responsive element.

Transcription of the murine laminin B1 (LB1) gene is induced by retinoic acid (RA), but responds only 24-28 h after RA treatment in F9 EC cells. Here we have shown by gel retardation assay that all three retinoic acid receptors (RARs) alpha, beta and gamma expressed in Cos cells can bind directly to the previously characterized retinoic acid response element (RARE) of the LB1 promoter, albeit with a weaker affinity than to the RAR-beta gene RARE. Three stereo-aligned TGACC-like motifs are crucial for this binding. Interestingly, the capacity of RAR-alpha, -beta and -gamma to bind the LB1 RARE appears to be differentially modulated by factor(s) present in HeLa cells infected with RAR-expressing vaccinia virus vectors. Analyses of LB1 RARE mutants provide a strong correlation between RA-inducibility in vivo and efficiency of RAR binding in vitro. Thus, RARs can participate directly in transcriptional induction of the LB1 gene, even though this induction is cycloheximide sensitive and RARs are present in F9 cells prior to RA addition.

A retinoic acid-responsive element is present in the 5' flanking region of the laminin B1 gene.

The retinoic acid (RA)-associated differentiation of murine F9 teratocarcinoma stem cells results in dramatic changes in gene expression. The cellular gene encoding the B1 subunit of the extracellular matrix protein laminin is transcriptionally activated by RA, and its transcription is further enhanced by N6,O2'-dibutyryladenosine 3',5'-cyclic monophosphate (Bt2cAMP) during the differentiation of F9 stem cells into extraembryonic parietal endoderm cells. We now report that expression vectors encoding the human RA receptors RAR-alpha, RAR-beta, and RAR-gamma can activate chloramphenicol acetyltransferase (CAT) expression from laminin B1 promoter/CAT expression vectors (e.g., p1.6LAMCAT) in RA-treated F9 cells, as measured in a transient transfection assay. Bt2cAMP does not further enhance the RA-associated increase in CAT activity. Through the use of deletion and mutation analyses, the RA-responsive element (RARE) of the murine laminin B1 gene has been defined as a 46-base-pair element between -477 and -432 of the laminin B1 5' flanking region. Insertion of a region of DNA containing this RARE in either orientation into a thymidine kinase promoter/CAT expression vector causes CAT expression to be activated 5- to 9-fold by the cotransfected human RAR-alpha or RAR-beta constructs in RA-treated F9 cells, and this RARE also functions in human HeLa cells. In contrast, this RARE in the p1.6LAMCAT vector does not activate CAT expression when cotransfected into F9 stem cells with the c-erbA gene in the presence of thyroid hormone. This suggests that the laminin B1 gene is activated by RA but not by thyroid hormone in vivo.

Cartilage type IX collagen-proteoglycan contains a large amino-terminal globular domain encoded by multiple exons.

Type IX collagen in cartilage consists of molecules composed of three genetically distinct polypeptide subunits. One of the subunits, alpha 2(IX), contains a covalently attached glycosaminoglycan side chain whereas a second subunit, alpha 1(IX), contains a large noncollagenous, amino-terminal domain called NC4. In this report, we describe for the first time the complete primary structure of this noncollagenous domain, based on cloning and sequencing of cDNA and genomic DNA as well as amino acid sequencing of tryptic peptides. Analysis of genomic clones has also allowed determination of the exon structure of NC4. Our results demonstrate that the noncollagenous, amino-terminal domain of alpha 1(IX) chains contains 266 amino acid residues (including the signal peptide) with 5 cysteinyl residues forming two disulfide bridges. The domain is basic with an estimated pI of 9.7, thus supporting the idea that it may participate in ionic interactions with polyanionic glycosaminoglycans in cartilage. Both the sequence and exon structure of the NC4 domain is unique among collagens and there is no obvious homology with the noncollagenous domains of other types of collagen, including the propeptides of fibrillar collagens.