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PubMed2006

Vascular anatomic variation in rabbits.

PURPOSE: To explore the vascular anatomic variation along the aortic arch in New Zealand White rabbits with the goal of highlighting potential anatomic configurations that might be encountered in the performance of preclinical endovascular research in rabbits. MATERIALS AND METHODS: Digital subtraction angiography images of the brachiocephalic artery (BCA) and aortic arch in New Zealand White rabbits were obtained after creation of elastase-induced aneurysms at the origin of the right common carotid artery (RCCA) in 214 animals. The patterns of origin of the RCCA and left common carotid artery (LCCA), right subclavian artery (RSCA) and left subclavian artery (LSCA), and right vertebral artery (RVA) and left vertebral artery (LVA) were analyzed. RESULTS: Five predominant variations of vessel origin were identified. In 200 of 214 cases (93%), the LCCA originated from the bifurcation of the BCA and aorta. In eight cases (4%), the LCCA directly originated from the aorta. In two cases (1%), the LCCA originated from the BCA. Aberrant RSCA anatomy in which the RSCA originated from the aortic arch instead of the BCA was found in three cases (1.5%). In a single case (0.5%), aberrant RSCA anatomy with the RVA originating from the BCA was encountered. CONCLUSIONS: Anatomic variation of the BCA in New Zealand White rabbits is similar to that seen in humans. Understanding of the normal and variant anatomy of the rabbit will aid investigators who use the rabbit model for endovascular research.

Angiography, Digital Subtraction↗
PubMedDate not supplied

Intradiscal electrothermal therapy (IDET).

The indications of discography include situations in which there is inconsistency between the imaging and physical findings. Discography may also be performed prior to planned disc therapy such as percutaneous diskectomy or IDET. The diagnostic goal of the diskcogram is to reproduce the patient's original pain pattern by injection of the disc. If it is determined that the origin of the patient's back pain is diskcogenic, disc therapy can be provided by either surgical or non-surgical means. The non-surgical disc therapy includes steroid injections, IDET, or even percutaneous diskectomy.

Adult↗
PubMed1988

The location of cues promoting selective reinnervation of axolotl muscles.

The selective reinnervation of muscles suggests that muscles have intrinsic recognition cues that promote selective synaptogenesis. For example, the anterior and posterior heads of the axolotl iliotibialis (ILT) muscle are preferentially reinnervated by their original motoneurons even after surgically exchanging them. The nature and location of cues that promote such selectivity are unknown, although previous work suggests that the muscle fibers themselves might harbor the relevant molecules. To address this question, we removed anterior and posterior ILT muscles, destroyed their myofibers by surgically damaging them and treating them with bupivacaine, and reimplanted them in either a normal or a reversed anterior/posterior orientation. After the regenerated myofibers became innervated, we stimulated different spinal nerves and recorded the synaptic potentials evoked in muscle fibers. Our results showed that if the muscles were removed, damaged, and reimplanted in their original positions, the segmental origin of inputs to the regenerated myofibers was similar to that seen in normal muscles and in muscles reimplanted with their myofibers intact. However, muscles that were removed and damaged but regenerated in new positions were innervated differently from normal muscles and from muscles whose myofibers survived transplantation. Thus, the site at which a muscle regenerates has an influence on the source of the muscle's reinnervation. Nevertheless, the innervation of muscles that regenerated after transplantation to a foreign site was not strictly appropriate for the new position, but was biased towards the muscle's original innervation pattern. Therefore, some, but not all, of the cues that reflect the original identity of the transplanted muscles survive the replacement of its myofibers.

Ambystoma↗
PubMed1985

Chronobiological aspects of stereotypy.

An area of research concerned with the temporal structure of stereotypic behavior, namely, the chronobiology of stereotypy, was reviewed. Nine studies in which investigators examined the long-term temporal structure of stereotypy of mentally retarded individuals were reviewed. Seven of them indicated that stereotypy occurs in a rhythmic pattern over time. The origins of these patterns were related to both exogenous and endogenous factors, such as staff and activity changes, metabolic functions, and the existence of a rest-activity cycle.

Arousal↗
PubMed1982

The cerebellar arteries: cortical patterns and vascularization of the cerebellar nuclei.

This paper reports an anatomical study of the vascular supply in 60 human cerebelli from subjects of both sexes, aged between 20 and 60 years, who had died of various accidental causes. The origin, branching pattern and cortical and central distributions of the cerebellar arteries have been studied by gross dissection, vascular injection and corrosion procedures. Variations of the normal pattern of the cerebellar arteries in both origin and cortical distribution are frequently found, the anterior inferior and the posterior inferior cerebellar arteries being the arteries showing the highest number of variations. The anomalies most frequently found are duplication in the origin, abnormal origin, and the presence of hypoplastic vessels. The cerebellar nuclei were supplied by the rhomboidal artery, a collateral branch of the superior cerebellar artery. The formation of a precise segmentary vascular pattern into the dentate nucleus by branches arising from the rhomboidal artery is described. The results are discussed in the light of other anatomical studies.

Adult↗
PubMed2005

[Use of FTIR and pattern recognition to determine geographical origins of Chinese medical herbs].

Geographical origin of medical herbs is an important factor of the quality of many traditional Chinese herbal medicines. The objective of this study is to investigate whether FTIR spectroscopy coupled with pattern recognition techniques could effectively discriminate geographical origins of medical herbs. Nearest neighbor method (NNM) and a SVM-based multiclass classifier were employed to discriminate 269 angelicae dahuricae radix (ADR) samples from 4 provinces in China and 380 salviae miltiorrhizae radix (SMR) samples from 6 provinces. A leave-one-out cross-validation accuracy of 99% was achieved by the multiclass classifier. The study shows this classification scheme can be a highly accurate approach for the discrimination of medical herbs of different origins.

Algorithms↗
PubMed2003

[Stabilizing selection and computer models of the joint evolution of patterns of polygenes, transposable elements, and origin identity labels].

A computer model of the populations dynamics of the patterns of polygenes, transposable elements (TEs), and origin identity labels (OILs) in the course of stabilizing selection for an additive quantitative trait (with the target value being 0.4 of the maximum) was analyzed. It was demonstrated that the final plateaus of the trait value and the frequencies of the active values of polygenes are reached rapidly, namely, within five to seven generations (the effective selection period). The inbreeding coefficient during this period also grows rapidly and then gradually increases eventually reaching approximately 0.7. The inbreeding coefficient reaches plateau (at approximately 1.0) only in generations 300-350, which suggests the effect of gene drift. Dendrograms of the patterns of polygenes, TEs, and OILs were constructed for all generations. By generation 100 of selection, the final patterns of TEs and OILs were not formed completely. Fixations and losses, especially those of the OIL pattern, were delayed. In general, however, the population heterogeneity with respect to the patterns studied does not stabilize. This heterogeneity decreases the case of stabilizing selection, although more slowly than in the cases of positive and negative selections.

Animals↗
PubMed1999

Phylogenetic Diversity and Population Densities of Culturable Cellulolytic Soil Bacteria across an Agricultural Encatchment.

> Abstract A typical, small encatchment (catena Bölkendorf) in the moraine, northeast German agricultural landscape Schorfheide-Chorin was studied with respect to summit, midslope, and foot-slope positions at northern and southern slope exposure, respectively, including a central noncultivated kettle hole position (pot hole). Across the sequence of seven distinct sampling positions, soil organic carbon and total nitrogen contents, soil gravimetric water content, and soil microbial biomass displayed maxima at the kettle hole position. Soil pH revealed a decreasing trend at the northern exposed slope and a minimum at the kettle hole position. Against this background, the population density of total culturable bacteria clearly displayed a minimum at the kettle hole position, whereas the population density of carboxymethylcellulose decomposing bacteria was not clearly differentiated in relation to sampling positions. To study the phylogenetic diversity of culturable cellulolytic bacteria, 311 isolates were obtained from the sampling positions across the entire encatchment and examined by restriction analysis of PCR-amplified 16S rDNA. Using the restriction enzyme ScrFI, isolates were classified into 31 pattern groups. Although the ratio of actinomycetes within total isolates ranged from 0.73 to 0.94, only 16 pattern groups originated from actinomycetes, but 15 from other bacteria. At all sampling positions, a dominant pattern group was identified, containing 38 to 65% of total isolates. Two site-specific pattern groups could be identified, representing significant parts of the total population, which were highly specific for the kettle hole (19% of total isolates) and for foot- and midslope positions (15-18% of total isolates), respectively. In general, the composition of cellulolytic isolates across the encatchment displayed differences with respect to slope positions, but was not significantly affected by soil properties. Based on 16S rDNA sequence analysis, isolates of the dominant as well as the specific pattern groups could be assigned to the genus Streptomyces. Furthermore, sequencing of 16S rDNA of isolates of another three pattern groups revealed a high phylogenetic diversity among these isolates, including cellulomonads and bacilli.http://link.springer-ny.com/link/service/journals/00248/bibs/37n4p238.html

Journal Article↗
PubMed2003

The course of the posterior inferior cerebellar artery may be related to its level of origin.

The course of the posterior inferior cerebellar artery (PICA) was analyzed with reference to its origin and relationships with the medullary and cerebellar surfaces and the adjacent cranial nerves in 40 brains after the injection with acrylic resins of the vertebrobasilar system. In 42.5% of instances, the PICA originated from the lateral medullary segment of the vertebral artery (VA), in 32.5% from its premedullary segment, in 22.5% from the basilar artery (BA), and in 2.5% it was absent. With reference to the level of origin, three patterns of course for the lateral medullary segment of the PICA can be outlined. (1) When it arises from the lateral medullary segment of the VA, it passes below the hypoglossal nerve, and the lateral medullary segment may form a loop with an anterosuperior convexity towards the pontomedullary sulcus (41%), or it may follow a rectilinear course (41%). It passes at the level of the accessory nerve. The tonsillomedullary (TM) segment shows a caudal loop and the telovelotonsillary (TVT) has a cranial loop. (2) When the PICA arises from the BA, it passes above the hypoglossal nerve. The lateral medullary segment forms a loop with lateral convexity (78%) and passes above or through the glossopharyngeal nerve, frequently showing a recurrent course among the roots of the IX, X, or XI cranial nerve. The TM and the TVT segments do not have loops. (3) When the PICA arises from the premedullary segment of the VA, it passes above, below, or through the rootlets of the hypoglossal nerve. In the lateral medullary segment, it follows a rectilinear course (54%) and passes the plane formed by the IX, X, and XI cranial nerves at an intermediate level with respect to the other two patterns. The TM and the TVT segments show caudal and cranial loops. The different origins and courses of the PICA derive from the selection of different branches of the primitive vertebrobasilar plexus during the development of the cerebellum. The existence of an embryologic correlation between the course of the PICA and its level of origin may be useful in the evaluation of its angiographic anatomy.

Adolescent↗
PubMed1998

A Mec1- and Rad53-dependent checkpoint controls late-firing origins of DNA replication.

DNA replication in eukaryotic cells initiates from many replication origins which fire throughout the S phase of the cell cycle in a predictable pattern: some origins fire early, others late. Little is known about how the initiation of DNA replication and the elongation of newly synthesized DNA strands are coordinated during S phase. Here we show that, in budding yeast, hydroxyurea, which blocks the progression of replication forks from early-firing origins, also inhibits the firing of late origins. These late origins are maintained in the initiation-competent prereplicative state for extended periods. The block to late origin firing is an active process and is defective in yeast with mutations in the rad53 and mec1 checkpoint genes, indicating that regulation of late origin firing may also be an important component of the 'intra-S-phase' checkpoint and may aid cell survival under adverse conditions.

Cell Cycle↗
PubMed1998

Involvement of Myc targets in c-myc and N-myc induced human tumors.

The myc proto-oncogenes are transcription factors that directly regulate the expression of other genes, by binding to the specific DNA sequence, CACGTG. Among the target genes for c-Myc regulation are ECA39, p53, ornithine decarboxylase (ODC), alpha-prothymosin and Cdc25A. In this study we examined the involvement of c-Myc target genes in human oncogenesis induced by c-myc or N-myc. In MCF-7 breast cancer cells, the induction of c-myc expression by estrogen was followed by the induction of all the Myc targets that we examined, indicating that those genes can serve as c-Myc targets in human oncogenesis. Moreover, in breast tumors exhibiting c-myc overexpression, several Myc targets were also overexpressed. A clear correlation between the expression of c-myc and its targets was also detected in Burkitt's lymphomas, which involve a specific translocation of c-myc gene, but not in other lymphoma cells. Yet, in cells derived from a neuronal origin the pattern of expression of Myc targets was more complex. In a neuroepithelioma cell line that overexpresses c-myc, only some targets were expressed. In addition in neuroblastomas, in which N-myc is amplified and overexpressed, only ODC was overexpressed in all cell lines, while all other target genes were expressed in only some of the cell lines. The more complex expression pattern found for the Myc targets in neuroblastomas suggests that genes that were identified originally as targets for c-Myc regulation may be regulated by N-Myc, but other cell specific factors are also needed for transcription of the target genes.

Breast Neoplasms↗
PubMed1985

The perforating branches of the middle cerebral artery. A microanatomical study.

The perforating branches (PFB's) of the middle cerebral artery (MCA) were studied in 34 unfixed brain hemispheres which were injected with a polyester resin and dissected under the operating microscope. Five hundred and eight vessels were identified and their site of origin, branching pattern, outer diameter (OD), and length recorded. Four hundred and two PFB's (79%) originated from the main trunk of the MCA before its division; the remaining 106 vessels (21%) had their origin from branches of the MCA as follows: superior trunk, 43 vessels (8.5%); inferior trunk, 30 vessels (6%); middle trunk, four vessels (0.8%); early temporal branch, 27 vessels (5.3%); and early frontal branch, two vessels (0.4%). The number of PFB's in each hemisphere varied from five to 29 (mean 14.9 +/- 0.7 vessels). The great majority of PFB's (96%) originated along the proximal 17 mm of the MCA. The PFB's arising in the first 10 mm had a mean OD of 0.35 +/- 0.01 mm and a mean length of 9.25 +/- 0.19 mm, and those arising from the second 10 mm had a mean OD of 0.47 +/- 0.02 mm and a mean length of 16.67 +/- 1.4 mm. A clear distinction between a medial and lateral group of PFB's was present in only 14 hemispheres (41%). In nine hemispheres (26%), perforating vessels from the anterior cerebral artery (A1 segment) and from the recurrent artery of Heubner replaced the medial group of PFB's of the MCA. In one case this group originated in an accessory MCA. In three hemispheres (9%) a small anastomosis (OD 0.2 mm) was seen between a PFB of the recurrent artery of Heubner and one of the MCA. From a total of 508 PFB's, 255 vessels (50%) originated as single vessels, while 253 vessels (50%) originated as branches of common stems. The OD of the single vessels ranged from 0.1 mm to 1.1 mm (mean 0.39 +/- 0.02 mm), and the length from 3 to 20 mm (mean 10.8 +/- 0.2 mm). The common stems ranged in OD from 0.6 to 1.8 mm (mean 0.87 +/- 0.04 mm), and in length from 1 to 15 mm (mean 4.1 +/- 0.4 mm). The clinical application of these anatomical data to the management of aneurysms and arteriovenous malformations of the MCA, and in the field of interventional neuroradiology is described. The most frequent pathological entities involving the perforating vessels are also discussed.

Adult↗
PubMed1997

Pattern-reversal visual evoked potentials in patients with epiretinal membrane.

PURPOSE: To determine the extent of pattern-reversal visual evoked potential parameter alteration by epiretinal membranes and to investigate the use of pattern-reversal visual evoked potential in the estimation of macular function in eyes with epiretinal membrane and in the fellow eyes. METHODS: In both eyes of 162 patients with epiretinal membrane, 92 of primary and 70 of secondary origin, pattern-reversal visual evoked potentials were recorded. Check sizes of 17', 10', and 7' (minutes of arc) were used. Parameters investigated were N80 and P100 latencies and P100 amplitude. RESULTS: No significant difference was detected between eyes with epiretinal membrane of primary and secondary origin regarding visual acuity and the pattern-reversal visual evoked potential parameters for the different check sizes. Compared with the fellow eyes, the eyes with epiretinal membrane had a significantly reduced visual acuity, prolonged N80 and P100 latencies, and a reduced P100 amplitude for the different check sizes. Compared with a separate control group (N = 20) with patients 50 to 59 years old, eyes with epiretinal membrane (N = 9) showed the same features as in the total group, but only for the 17' and 10' check sizes. The fellow eyes (N = 9) showed a significant reduction of the P100 amplitude (P < .05) for the pattern sizes of 17' and 10', but no difference in visual acuity or pattern-reversal visual evoked potential latency was found. CONCLUSIONS: In eyes with epiretinal membrane, pattern-reversal visual evoked potential latencies are prolonged, and amplitude is reduced. Relationships between clinical parameters and pattern-reversal visual evoked potential parameters require further study.

Evoked Potentials, Visual↗
PubMed1975

Proceedings: Prognosis of non-Hodgkin's lymphomas with special emphasis on the staging classification.

The prognosis of the non-Hodgkin's lymphomas is determined by 1. the pattern of origin and spread which can be demonstrated in a staging classification, 2, the histopathological type, and 3. the effectiveness and scope of the treatment methods, particularly radio- and chemo-therapy. In the following paper the Ann Arbor Classification, which was originally conceived of for both disease groups (Hodgkin's and non-Hodgkin's lymphomas), is discussed particularly with respect to the applicability and prognostic evaluation for the non-Hodgkin's lymphomas. The Ann Arbor Classification may in essence reflect the oncological characteristics of the non-Hodgkin's accurately; there are, however, a number of findings with qualitative and quantitative differences which defy integration into the Ann Arbor Classification. The qualitative differences consist of the differing lymphatic and extralymphatic origins and their consequence for spread and prognosis. The quantitative differences refer to the varying patterns of distribution of the different stages of spreading, whereby the dissemination stages in the non-Hodgkin's lymphomas are more dependent on the histological form than is the case with the Hodgkin's lymphomas, and thus must play a greater role in the prognostic evaluation and indication for treatment. Suggestions have been made for a modification of the Ann Arbor Staging Classification for the non-Hodgkin's lymphomas.

Humans↗
PubMed1989

Autocatalytic ftz activation and metameric instability induced by ectopic ftz expression.

Inappropriate expression of the Drosophila pair-rule gene, fushi tarazu (ftz), causes cuticular pattern deletions apparently complementary to those in ftz larvae. We show that the two patterns actually originate similarly, in both cases affecting the even-numbered parasegmental boundaries. The reciprocal cuticular patterns derive from differing patterns of selector gene expression (homoeotic transformations). The primary effect of ectopic ftz activity is to broaden ftz domains by autocatalytic activation of endogenous ftz expression in an additional anterior cell. This activates engrailed (en) and represses wingless (wg) expression, consistent with their proposed combinatorial control by ftz (and other pair-rule genes) to define parasegmental primordia. We propose that the anterior margin of each ftz stripe is normally defined by the posterior even-skipped (eve) boundary.

Animals↗
PubMed2001

Biological variability of fecal calprotectin in patients referred for colonoscopy without colonic inflammation or neoplasm.

OBJECTIVE: Fecal calprotectin concentration in stool has recently been proposed as a marker of colonic neoplasm and inflammation, but the intraindividual day-to-day variability has so far received little attention. The present study was undertaken to determine the biological variability of fecal calprotectin in patients referred for colonoscopy. METHODS: A prospective design was applied. In each of 14 consecutive patients submitted for colonoscopy, eight stool samples were collected before the endoscopy. A detailed questionnaire was used. Calprotectin was measured by quantitative enzyme-linked immunoassay, and standard deviation for the within-patient variability was estimated from one-way analysis of variance. RESULTS: In absence of colonic neoplasm and inflammation, two populations of patients emerged: one (36%) with remarkably low and stable fecal calprotectin values all within the recommended cut-off of 50 microg/g, and one (64%) with labile values also beyond this limit. In this latter group. fecal calprotectin was 70 microg/g (mean) (single tests ranged from 9 to 461), and SD within patients was 52 microg/g, showing considerable day-to-day variation. History, concurrent diseases, or findings at colonoscopy could not explain labile values. A similar pattern was observed for spot variation in one stool sample from healthy volunteers, suggesting that factors other than disease contribute to the significant intraindividual biological variation of fecal calprotectin. CONCLUSIONS: Day-to-day variation of fecal calprotectin is considerable in patients without colonic inflammation or neoplasm, for whom the pattern of stabile low fecal calprotectin may seem to be a valid negative predictor. The origin and pattern of fecal calprotectin excretion deserve further attention.

Adult↗
PubMed1989

Retinoic acid induces a pattern of digits in anterior half wing buds that lack the zone of polarizing activity.

Wing buds whose posterior half is excised, develop into wings lacking distal structures. However, such experimentally generated preaxial half wing buds can be rescued by implanting a retinoic-acid-releasing bead at their anterior margin. The polarity of the pattern that originates from preaxial half wing buds is reversed. For example, instead of a 234 digit pattern typical for normal wings, the order of digits is 432. This result implies that retinoic acid has the capacity to reprogram anterior limb bud tissue, and that the resulting change in cell fate does not depend on the presence of posterior tissue regions such as the zone of polarizing activity (ZPA).

Animals↗
PubMed1997

A pattern classification procedure integrating the multivariate statistical analysis with neural networks.

A new procedure integrating multivariate statistical analysis with artificial neural networks (ANN) for complex pattern classification is proposed. Firstly, a specially designed statistical analysis algorithm called correlative component analysis (CCA) was used to identify the classification characteristics (CC) from original high-dimensional pattern information. These CC were then used as input data to the ANN for pattern classification. The proposed new procedure not only effectively decreased the dimensionality of original patterns, but also took advantage of the self-learning power of the ANN. Further, a typical example of classifying natural spearmint essence was employed to verify the effectiveness of the new pattern classification method. The study showed that this novel integrated procedure provides better results than those obtained using individual methods separately.

Algorithms↗