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PubMed1997

Lamina VII and VIII neurons of the S2 segment bilaterally projecting to the C6 segment of the spinal cord in the cat.

Intracellular and extracellular recordings of antidromic action potentials were applied to investigate neurons of the S2 segment projecting to the C6 segment of the cat spinal cord. The cell bodies were located in laminae VII and VIII of the gray matter while axons ascended in lateral funiculi. Thirty-two out of the total 45 neurons were found to project to the C6 segment bilaterally, seven ipsilaterally and six contralaterally. The axonal conduction velocities were in the 42-96 m/s range and in some neurons were significantly lower in distal parts of axons, supposing that some neurons may give off collateral branches to various segments of the spinal cord. It is discussed if the investigated neurons form a part of the propriospinal system or if their cervical projections are only collaterals of long tracts ascending to supraspinal levels. The organisation of the presented connections between spinal enlargements indicates their contribution in complex mechanisms of co-ordination of movements of the limbs.

Action Potentials↗

PubMed1999

NMR observation of selected segments in a larger protein: central-segment isotope labeling through intein-mediated ligation.

Peptide segments in a protein, which can include an active site of interest or be a series of parts constituting the entire structure, are now selectively observed by nuclear magnetic resonance (NMR) spectroscopy using samples prepared by the intein-mediated ligation method. Two separate inteins were used to ligate NMR-transparent segments to both the ends of an NMR-visible segment, producing a partly visible intact protein molecule. The (15)N-(1)H correlation spectrum of a 370-residue maltose binding protein labeled with (15)N at a continuous segment comprising residues Gly(101)-Ser(238) showed the essential elimination of signal overlapping, the signals being at the same positions as for the uniformly labeled sample. This method will allow structural analysis by NMR of over 50-kDa proteins in combination with contemporary NMR techniques suppressing the signal decays of larger proteins.

ATP-Binding Cassette Transporters↗

PubMed2001

ST-segment depression in lead aVR predicts predischarge left ventricular dysfunction in patients with reperfused anterior acute myocardial infarction with anterolateral ST-segment elevation.

BACKGROUND: Patients with an anterolateral acute myocardial infarction (AMI) have a worse prognosis, and those with additional inferolateral wall involvement might be higher risk because of more extensive area at risk. Lead -aVR obtained by inversion of images in lead aVR has been reported to provide useful information for inferolateral lesion. METHODS: We examined the relation between ST-segment deviation in lead aVR on admission electrocardiogram (ECG) and left ventricular function in 105 patients with an anterolateral AMI undergoing successful reperfusion < or = 6 hours after onset. Patients were classified according to ST-segment deviation in lead aVR on admission ECG: group A, 23 patients with ST elevation of > or = 0.5 mm; group B, 47 patients without ST deviation; and group C, 35 patients with ST depression of > or = 0.5 mm. RESULTS: There were no differences among the 3 groups in age, sex, or site of the culprit lesion. In groups A, B, and C, the peak creatine kinase level was 3661 +/- 1428, 4440 +/- 1889, and 6959 +/- 2712 mU/mL, and the left ventricular ejection fraction (LVEF) measured by predischarge left ventriculography was 54% +/- 9%, 48% +/- 7%, and 37% +/- 9%, respectively(P < .01). During hospitalization, congestive heart failure occurred more frequently in group C than in groups A or B (P < .05). ST-segment depression in lead aVR had a higher predictive accuracy than other ECG findings in identifying patients with predischarge LVEF < or = 35%. CONCLUSIONS: We conclude that in patients with an anterolateral AMI, ST-segment depression in lead aVR on admission ECG is useful for predicting larger infarct and left ventricular dysfunction despite successful reperfusion.

Adult↗

PubMed1996

Multiple DNA and protein sequence alignment based on segment-to-segment comparison.

In this paper, a new way to think about, and to construct, pairwise as well as multiple alignments of DNA and protein sequences is proposed. Rather than forcing alignments to either align single residues or to introduce gaps by defining an alignment as a path running right from the source up to the sink in the associated dot-matrix diagram, we propose to consider alignments as consistent equivalence relations defined on the set of all positions occurring in all sequences under consideration. We also propose constructing alignments from whole segments exhibiting highly significant overall similarity rather than by aligning individual residues. Consequently, we present an alignment algorithm that (i) is based on segment-to-segment comparison instead of the commonly used residue-to-residue comparison and which (ii) avoids the well-known difficulties concerning the choice of appropriate gap penalties: gaps are not treated explicity, but remain as those parts of the sequences that do not belong to any of the aligned segments. Finally, we discuss the application of our algorithm to two test examples and compare it with commonly used alignment methods. As a first example, we aligned a set of 11 DNA sequences coding for functional helix-loop-helix proteins. Though the sequences show only low overall similarity, our program correctly aligned all of the 11 functional sites, which was a unique result among the methods tested. As a by-product, the reading frames of the sequences were identified. Next, we aligned a set of ribonuclease H proteins and compared our results with alignments produced by other programs as reported by McClure et al. [McClure, M. A., Vasi, T. K. & Fitch, W. M. (1994) Mol. Biol. Evol. 11, 571-592]. Our program was one of the best scoring programs. However, in contrast to other methods, our protein alignments are independent of user-defined parameters.

Algorithms↗

PubMed2000

Correlations between joint and spinal mobility, spinal sagittal configuration, segmental mobility, segmental pain, symptoms and disabilities in female homecare personnel.

The aim of a study comprising 607 women working as homecare personnel was to investigate general spinal, joint and segmental mobility, different symptoms (pain and strain) and their relation to various aspects of disability. Joint mobility (mainly peripheral) was estimated using the "Beighton" score and spinal posture and mobility were measured by kyphometer. Passive segmental mobility and pain provocation were estimated manually. Pain intensity and strain during work and leisure were estimated using visual analogue scales for defined anatomical regions. Disability was rated using defined items and two indices. The 7-day prevalence of low back pain was 48%. Peripheral joint mobility, spinal sagittal posture and thoracic sagittal mobility showed low correlations with disability. Lumbar sagittal hypomobility was associated with higher disability. Manually estimated segmental mobility and segmental pain provocation of L4-L5 and L5-S1 correlated with disability; hypo- and hypermobility or positive pain provocation tests at these levels showed higher disability than normal mobility and negative pain provocation tests, respectively. Cluster analysis revealed that the combination of positive pain provocation tests and low lumbar sagittal mobility was associated with particularly high disability levels. In conclusion, positive pain provocation tests were clearly associated with high disability levels.

Activities of Daily Living↗

PubMed1996

Neutrophil nuclear segmentation in mild cobalamin deficiency: relation to metabolic tests of cobalamin status and observations on ethnic differences in neutrophil segmentation.

Neutrophil hypersegmentation is considered the most sensitive peripheral blood cell marker of cobalamin deficiency. However, its diagnostic value in the mild deficiency states that accompany most low cobalamin levels and its relation to metabolic test of cobalamin status are unknown. The authors compared neutrophil lobe averages and percent neutrophils with 5 or more lobes (%5+ lobes) in 169 subjects with their mean corpuscular volume (MCV) and serum cobalamin, methylmalonic acid (MMA), homocysteine, and folate levels and, in 65 cases, with the deoxyuridine suppression test (dUST). Only 9 subjects had hypersegmentation by lobe average and 20 subjects by %5+ lobes. They were not more often cobalamin-deficient than subjects without hypersegmentation. Moreover, only one of 34 subjects with dUST results diagnostic for cobalamin deficiency had neutrophil hypersegmentation. Both indices of neutrophil segmentation in the 169 subjects correlated significantly with homocysteine levels. They also showed weak inverse correlation with cobalamin levels, but did not correlate with MMA, folate, or MCV values. Cobalamin therapy for 6 months did not significantly change neutrophil lobe averages in 35 subjects with mild deficiency, compared with 8 nondeficient controls, and only marginally improved the %5+ lobes. A surprising, incidental observation was that blacks had significantly greater neutrophil segmentation by both criteria than did whites and others. This difference was unrelated to cobalamin or folate status. Our results indicate that dUST abnormalities precede all morphologic changes of deficiency, including hypersegmentation. Although a tendency exists for neutrophil segmentation to increase very slightly as some serum values, especially homocysteine, start to worsen in mild cobalamin deficiency, the metabolic changes precede overt hypersegmentation. Neutrophil nuclear segmentation is insufficiently sensitive in relation to metabolic evidence of deficiency to be used as a clinical tool in the diagnosis of mild cobalamin deficiency.

Asian People↗

PubMed1999

DIALIGN 2: improvement of the segment-to-segment approach to multiple sequence alignment.

MOTIVATION: The performance and time complexity of an improved version of the segment-to-segment approach to multiple sequence alignment is discussed. In this approach, alignments are composed from gap-free segment pairs, and the score of an alignment is defined as the sum of so-called weights of these segment pairs. RESULTS: A modification of the weight function used in the original version of the alignment program DIALIGN has two important advantages: it can be applied to both globally and locally related sequence sets, and the running time of the program is considerably improved. The time complexity of the algorithm is discussed theoretically, and the program running time is reported for various test examples. AVAILABILITY: The program is available on-line at the Bielefeld University Bioinformatics Server (BiBiServ) http://bibiserv.TechFak.Uni-Bielefeld.DE/dial ign/

Algorithms↗

PubMed1999

Significant differences in the frequency of transcriptional units, types and numbers of repetitive elements, GC content, and the number of CpG islands between a 1010-kb G-band genomic segment on chromosome 9q31.3 and a 1200-kb R-band genomic segment on chromosome 3p21.3.

We determined the nucleotide sequence of the entire 1,010,525-bp insert contained in CEPH YAC clone 867e8. This human genomic segment was derived from chromosome 9q31.3 and corresponds to a G-band region. We compared this segment, in terms of structure, with a previously characterized 1,201,033-bp sequence in CEPH YAC936c1 that had come from a portion of human chromosome 3p21.3 corresponding to an R-band region. The two segments were significantly different with respect to the frequency of transcriptional units, the types and numbers of repetitive elements present, their GC content, and the number of CpG islands. Alu elements, GC content, and CpG islands all showed positive correlations with the abundance of exons, but the distribution of LINE1s did not. These observations might reflect an influence of the first three of these features on the functions or expression of genes in the respective regions. In addition to a novel gene (F36) lying at the centromeric end of the 9q segment, we found a cluster of placenta-specific genes within a small section (about 400 kb) on the telomeric side of YAC867e8. This cluster consisted of four apparently unrelated ESTs and two genes, pregnancy-associated plasma protein-A (PAPP-A) and a novel gene (tentatively named EST-YD1). Our characterization of the two chromosomal regions provided evidence that genes are not evenly distributed throughout the human genome, and that gene richness is correlated with the GC content and with the frequency of either Alu elements or CpG islands.

Alu Elements↗

PubMed1983

Cloning and sequence of UK bovine rotavirus gene segment 7: marked sequence homology with simian rotavirus gene segment 8.

The genome of the UK bovine rotavirus, which consists of eleven segments of dsRNA was polyadenylated and reverse-transcribed into cDNA. Complementary cDNA strands were annealed and the termini of the duplexes completed using DNA polymerase I. Full-length DNA copies of RNA segments 7, 8 and 9 were cloned into the Pst I site of pBR322 and a clone containing the entire gene 7 was identified and sequenced. Gene 7 is 1059 nucleotides in length and contains a single long open reading frame capable of coding for a protein of 317 amino-acids. The known gene product of segment 7 is a protein with an estimated molecular weight of 33,000 daltons. When the UK bovine rotavirus gene 7 sequence was compared with the published data for the homologous gene (segment 8) of the simian rotavirus SA11, it was found to be identical to it in size and the arrangement of the proposed coding and non-coding regions, and very similar in nucleotide sequence (88% homology). Most of the base changes are silent and the predicted amino-acid sequences are almost identical (96% homology).

Amino Acid Sequence↗

PubMed1983

The sequence of RNA segment 1 of influenza virus A/NT/60/68 and its comparison with the corresponding segment of strains A/PR/8/34 and A/WSN/33.

The complete nucleotide sequence of RNA segment 1 of influenza virus A/NT/60/68, corresponding to the PB2 protein, has been determined. It is 2341 nucleotides long, encoding a predicted product of 759 amino acids with a net charge of +27 1/2 at neutral pH. The predicted amino acid sequence has been compared to the equivalent sequences in influenza viruses A/PR/8/34 and A/WSN/33. Evolutionary divergence, assuming a direct lineage from A/PR/8/34 and allowing for "laboratory drift", is 0.08% per year. The alignment of RNA segment 10 of A/NT/60/68 with segments 1 and 3 is completed, confirming that it is a mosaic of regions from these two segments.

Amino Acid Sequence↗

PubMed1992

The nucleotide sequence of the M RNA segment of tomato spotted wilt virus, a bunyavirus with two ambisense RNA segments.

The complete sequence of the tomato spotted wilt virus (TSWV) M RNA segment has been determined. The RNA is 4821 nucleotides long and has an ambisense coding strategy similar to that of the S RNA segment. The M RNA segment contains two open reading frames (ORFs), one in the viral sense which encodes a protein with a predicted size of 33.6K, and one in the viral complementary sense which encodes the precursor to the G1 and G2 glycoproteins, with a predicted size of 127.4K. Both ORFs are expressed via the synthesis of subgenomic mRNAs that possibly terminate at a stable hairpin structure, located in the intergenic region. The precursor for the glycoproteins contains a sequence motif (RGD) which is characteristic of cellular attachment domains. Significant sequence homology was found between the G1 glycoproteins of members of the genus Bunyavirus and a corresponding region in the glycoprotein precursor of TSWV, indicating a close evolutionary relationship between these viruses. With the elucidation of the M RNA sequence, the complete nucleotide sequence of TSWV has been determined. TSWV represents the first member of the Bunyaviridae shown to contain two ambisense RNA segments.

Amino Acid Sequence↗

PubMed1998

Triple projections of neurones located in S1 and S2 segments of the cat spinal cord to the C6 segment, the cerebellum and the reticular formation.

Electrophysiological investigation of neurones in sacral segments of the spinal cord was performed in alpha-chloralose-anaesthetized cats in order to establish whether at least some ascending tract neurones could diverge to three different centres located in the brainstem, the cerebellum or the spinal cord. Recordings of antidromic action potentials from cells in S1 and S2 segments were taken following stimulation of the contralateral gigantocellular nucleus, contralateral restiform body and ipsi- and contralateral grey matter of the C6 spinal segment. Antidromic responses allowed identification of several types of neurones that differed in their pattern of supraspinal or propriospinal projections. In eighteen out of a total of sixty-three neurones triple projections to all the above structures were found. In the majority of cells investigated their axons divided into two branches ascending both ipsi- and contralaterally in the lateral funiculi of the spinal cord. Their cell bodies were distributed in laminae VII-VIII except for a minor group of neurones that projected to the C6 segment only, which were located in laminae V-VI. The latter group also displayed lower values of axonal conduction velocities. Comparison of conduction velocities in proximal and distal parts of axons revealed significant slowing in most, raising the possibility that additional collaterals were present to other spinal or supraspinal centres. Dual and triple projections from most cells in this study suggest that such a divergence may be a more common feature of ascending tract neurones than has been reported before.

Action Potentials↗

PubMed1992

Interference is controlled by segment 2 and possibly by segment 8 of the nondefective interfering influenza virus variant A/FM/1/47-MA.

On mouse adaption of A/FM/1/47, a variant, A/FM/1/47-MA (FM-MA), that had acquired the properties of increased virulence and interference was produced. Coinfection of cells with FM-MA and prototype strains of influenza virus yielded > 100-fold more FM-MA virus than prototype virus, whereas coinfection with the same prototype strains and the parental A/FM/1/47 virus produced equivalent yields, indicating that FM-MA had acquired mutations that confer the property of interference during mouse adaption. FM-MA is a nondefective interfering virus that grows to a high titer in vivo and in vitro. It has previously been shown that segments 4, 7, and 8 and possibly segment 5 account for the increased virulence. In this study we show by genetic analysis of FM-MA x A/HK/1/68 reassortants that segment 2, coding for the polymerase-associated protein PB1, and possibly segment 8, encoding the NS1 and NS2 proteins, control the ability of FM-MA to interfere. Interference could not be overcome by increasing the titer of the coinfecting strain, but delaying FM-MA infection by 4 to 6 h did avoid interference. During interference of A/HK/1/68, protein synthesis was inhibited by less than 65% throughout coinfection. Given the kinetics of interference and the small perturbation in protein synthesis, interference appeared to occur at the level of late genome replication or virus assembly. Virulence and interference in FM-MA were not linked. An interfering avirulent FM-MA x A/HK/1/68 reassortant, E07, was capable of protecting mice against lethal pneumonia due to a virulent noninterfering reassortant, H04.

Genetic Variation↗

PubMed1997

Bilateral projection of neurones of the C6 segment to S1 and S2 segments of the spinal cord in the cat.

Sacral projections of neurones located in the C6 segment of the spinal cord were electrophysiologically investigated in alpha-chloralose anaesthetized cats. The cell bodies were found mainly in lamina VIII and in the ventromedial part of lamina VII of the C6 segment. At the thoracic level their axons descended in lateral funiculi, mostly on both sides and only exceptionally contra- or ipsilaterally. However, bilateral projection to sacral segments was less frequent (25 neurones). It is concluded that axons terminate at different levels on both sides of the spinal cord and only part of them project bilaterally to S1/S2 segments. Conduction velocities calculated for all the axons varied from 38 to 80 m/s and were significantly slower for their distal parts. Therefore it is suggested that descending axons send collaterals at various spinal levels. The presented data indicate the importance of these neurones for interlimb coordination.

Animals↗

PubMed1991

Site-specific recombination promoted by a short DNA segment of plasmid R1 and by a homologous segment in the terminus region of the Escherichia coli chromosome.

A short DNA segment located in the kanamycin resistance region of plasmid R1 promotes site-specific recombination and plasmid maintenance. This segment has been reduced to 100 bp and subsequently to 44 bp without losing these properties. It can recombine with a similar segment located in the terminus region of the Escherichia coli chromosome. It is proposed that this recombination is responsible for the plasmid maintenance properties of the R1 segment. The chromosomal site has been isolated; it also shows site-specific recombination activity. Sequence homologies were also found with a phage site-specific integration locus in the chromosome of Xanthomonas campestris and with the plasmid ColE1 site-specific recombination locus. The recombinase required in all these systems is probably XerC, an E. coli enzyme acting on the cer site of plasmid ColE1 for the conversion of plasmid dimers to monomers. It is postulated that site-specific recombination in the terminus region of the chromosome intervenes in the partitioning of the two daughter chromosomes.

Bacterial Proteins↗

PubMed1989

[ST-segment analysis in long-term ECG: amplitude and phase response of various systems in comparison with standard ECG and their effect on true original reproduction of ST segment depression].

Ambulatory ECG monitoring has been suggested as a method for the detection of transient myocardial ischemia. But it is still unclear how accurately ST-segment alterations can be detected with the different systems. Measurement of amplitude and phase response is a valid method to estimate the fidelity of reproduction of an ECG-signal. We investigated the direct-recording long-term ECG systems CardioData Mk4 with recorder PR3, CardioData Mk4 with Spacelabs recorder, DMI Eclipse with DMI Recorder, Reynolds Pathfinder II with Oxford replay PB2 and recorder MR-10 and Reynolds Pathfinder III with tracker in comparison to a standard ECG recorder Picker Schwarzer C6800. Amplitude vs frequency response curves were derived from input sinus waves ranging from 0.01 to 500 Hz. The phase response was measured with a phase-sensitive waveform at a frequency range from 0.05 to 10 Hz. To determine the distortion of the ST-segment on the actual ECG, we produced a standard PQRST-signal that was modified to provide flat ST-segment depressions from 0 to 0.5 mV at 0.05 mV increments. The low and high frequency cut-off of the amplitude response was found at 0.09 and 220 Hz with the standard ECG recorder. A phase shift of -30 degrees was detected at 0.07 Hz. ST-segment depressions of the test-ECG were reflected to the same extent. For the CardioData-System, both cassette recorders yielded lower and upper cut-off frequencies of 0.06 and 0.07, and 20 and 16 Hz, respectively. A phase shift of -30 degrees was found at 0.35 and 0.31 Hz, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗

PubMed1986

Does complete revascularization by the conventional method truly provide the best possible results? Analysis of results and comparison with revascularization of infarct-prone segments (systematic segmental myocardial revascularization): the Sheba Study.

Myocardial revascularization is usually considered "complete" if all stenosed major coronaries are bypassed. Attempts were made to compare the results of this method with an approach by which each of the following five left ventricular infarct-prone segments is revascularized if ischemic: anteroseptal, anterolateral, posterosuperior, posteroinferior, and diaphragmatic. Two subsets of patients were studied. A total of 366 patients (Group A) who underwent aortacoronary bypass operations from 1980 to 1982 were followed up for a mean of 16.3 (6 to 43) months and were retrospectively divided into two groups: Group A1 (120 patients) had incomplete segmental revascularization (mean of 3.4 grafts per patient) and Group A2 (246 patients) had complete segmental revascularization (4.0 grafts per patient) (p less than 0.0001). Groups A1 and A2 were identical in all clinical and angiographic parameters: unstable angina, 60%; previous myocardial infarction, 70%; left main stenosis, 10%; and ejection fraction less than 30%, 2%. Overall operative mortality was 2.3%. Results in Groups A1 and A2, respectively, were as follows: operative mortality, 5.8% versus 0.8% (p less than 0.005); perioperative myocardial infarction, 6.9% versus 0.8% (p less than 0.0005); 35 month survival rate, 93.3% versus 97.9% (p less than 0.02); total freedom from symptoms, 54.1% versus 68.3% (p less than 0.025). In addition, 151 patients operated on in 1984 (Group B) were studied prospectively with regard to operative mortality and perioperative myocardial infarction, and the results were identical to those in Group A. Compared to conventional complete revascularization, complete segmental revascularization provides better results.

Adult↗

PubMed1979

[Signs of anterior segment ischemia following segmental external buckling (author's transl)].

The symptoms of an acute anterior segment necrosis are described as they might occur as a postoperative complication due to encircling procedures. Report about a patient presenting postoperatively signs of ischemia in the anterior segment following segmental external buckling. In this case the cylinder of the explant was 5 mm in diameter and extended over 2 quadrants of the globe. Discussion of the factors most likely causing this rare complication due to segmental external buckling.

Aged↗