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PubMed2004

The sleep slow oscillation as a traveling wave.

During much of sleep, virtually all cortical neurons undergo a slow oscillation (<1 Hz) in membrane potential, cycling from a hyperpolarized state of silence to a depolarized state of intense firing. This slow oscillation is the fundamental cellular phenomenon that organizes other sleep rhythms such as spindles and slow waves. Using high-density electroencephalogram recordings in humans, we show here that each cycle of the slow oscillation is a traveling wave. Each wave originates at a definite site and travels over the scalp at an estimated speed of 1.2-7.0 m/sec. Waves originate more frequently in prefrontal-orbitofrontal regions and propagate in an anteroposterior direction. Their rate of occurrence increases progressively reaching almost once per second as sleep deepens. The pattern of origin and propagation of sleep slow oscillations is reproducible across nights and subjects and provides a blueprint of cortical excitability and connectivity. The orderly propagation of correlated activity along connected pathways may play a role in spike timing-dependent synaptic plasticity during sleep.

Adult↗
PubMed1989

Origins of the prestalk-prespore pattern in Dictyostelium development.

Using cell-autonomous markers we have traced the origins of prespore cells and two types of prestalk cells (pstA and pstB cells) during slug formation. We show that cell sorting and positional information both contribute to Dictyostelium morphogenesis. The initial pattern established at the mound stage is topologically quite different from that of the slug. Confirming previous studies, we find that prespore cells occupy most of the aggregate but are absent from a thin layer at the base and from the emerging tip. PstB cells are almost entirely localized to the basal region during the early stages of tip formation. Thus prespore and pstB cell differentiation appear to occur in response to localized morphogenetic signals. In the case of pstB cells, these signals presumably emanate from the base and not, as might be expected, from the tip. When first detectable, pstA cells are scattered throughout the aggregate. They then appear to migrate to the apex, where the tip forms.

Antigens, Polyomavirus Transforming↗
PubMed1994

Congenital abnormalities associated with limb deficiency defects: a population study based on cases from the Hungarian Congenital Malformation Registry (1975-1984).

Limb deficiency defects (LD) occurring among 1,575,904 births in Hungary during 1975-1984 were reviewed. The overall birth prevalence of LD was 1 in 1,816. This paper discusses the nature and distribution of the limb and other defects in the 275 (32%) children who had structural malformations in other systems. Two main forms of classification were used: morphologic and causal. Additional malformations were most commonly seen in infants with amelia, rudimentary limb (RL), radial/tibial (RT), intercalary or central axis (CA) LD and rarely in those with terminal transverse (TT) or ulnar/fibular (UF) defects. Upper limbs (81%) were involved significantly more often than lower limbs (42%) and there were more right-sided defects (83% vs. 71%) due to an excess of right arm involvement especially with radial ray and split hand anomalies. Single limb involvement was relatively common with amelia (88%), UF (82%), RT (50%), and TT (50%) defects. With other LD, multimelic involvement was more characteristic. This was usually symmetric with intercalary and RL defects but asymmetric with CA anomalies and digital deficiencies (DD). From a causal perspective, 17% of cases had genetic disorders, 52% had recognized associations, anomalies, sequences, environmental causes or patterns of unknown origin, and 31% had unknown patterns of malformations. The commonest entities were amnion disruption sequence (16% of cases) and VACTERL association (8%). Both of these disorders showed unusual temporal distribution. As anticipated, patterns of malformations differed with the type of LD. Amelia and digital amputations were often seen with body wall defects, atypical anencephaly or encephalocele, and cleft lip reflecting amnion disruption. Rudimentary limb was seen with anencephaly, omphalocele, renal agenesis, aberrant genitalia, and imperforate anus, reflecting defects of blastogenesis including the cloacal exstrophy and caudal regression sequences and Schisis association. Radial/tibial defects were associated with different patterns depending on whether the limb defects were unilateral or bilateral. Unilateral defects occurred with anomalies suggesting VACTERL association or the facio-auriculo-vertebral anomaly, while bilateral defects occurred more often in genetic or potentially genetic disorders including VACTERL with hydrocephalus. Central axis defects showed three main patterns of association: one reflecting the ectrodactyly-ectodermal dysplasia-clefting syndrome; one with tongue anomalies representing a variant of oro-mandibular-limb (Hanhart) anomaly, and the last with hydronephrosis indicating a group of "acro-renal" syndromes. Strong associations with other anomalies were not seen in the groups with TT, UF, or intercalary defects.

Abnormalities, Multiple↗
PubMedDate not supplied

Evaluation of computerized medical diagnostic decisions via fuzzy sets.

Two of the greatest obstacles in medical data processing can be summarized as 'multiclass and noncrisp membership of the patterns' and originate from the fact, that one patient can suffer in different degrees from more than one disease simultaneously. Some encouraging results have been obtained applying to these problems a fuzzy pattern recognition model instead of the purely statistical one. A criterion for evaluation of fuzzy classification accuracy has been developed. In this paper, its general form is presented and appropriately discussed. A composed form of the criterion is suggested, which consists of three components - Integral Index of Classification. Highest Discrepancy Index of Classification and Highest Coincidence Index of Classification. Three graphical examples have been designed in order to clear up the underlying idea. The implementation of the criterion is illustrated by experiments with real data from medical practice.

Atmospheric Pressure↗
PubMed1984

Pattern ERG of the cat.

Recent reports on pattern ERGs reopened the discussion of pattern or luminance origin of the ERG to pattern reversal stimulation. In this report cat ERGs to checkerboard stimuli were recorded. The stimulus parameters were manipulated in order to vary the strength of local luminance and contrast stimulation independently. Special care was taken to eliminate stray light effects. The results clearly show that pattern specific components in the cat ERG, if present at all, are no greater than the variance of the responses from local luminance nonlinearities. Thus a "Pattern ERG" can be recorded by luminance modulation.

Action Potentials↗
PubMed2004

Ordered microstructures by assembly of ABC 3-miktoarm star terpolymers and linear homopolymers.

Ordered microstructures assembled from the mixture of the ABC 3-miktoarm star terpolymers and the linear homopolymers have been investigated by using dynamic density functional theory. The simulations reveal that completely different ordered microphase pattern is found with addition of a few percent homopolymers that is identical in component to one of the arms on the ABC 3-miktoarm star terpolymer. For example, the original density pattern of ABC 3-miktoarm star terpolymers with parameters of N(A)=N(B)=N(C)=10 and chi(AB)=0.90, chi(BC)=chi(CA)=0.45 is in a perfectly ordered knitting feature. However, with gradual addition of the linear polymer same as block C on ABC 3-miktoarm star terpolymer into the system, the density patterns evolve with the volume fraction of the linear polymer from the ordered knitting patterns into the hexagonal patterns. Furthermore, with addition of linear polymers same as block A, lamellar microstructure has finally resulted. The simulation points out a way for designing and manufacturing nanomaterials with totally different microstructures.

Journal Article↗
PubMed2001

Amelogenesis imperfecta: diagnosis and resolution of a case with hypoplasia and hypocalcification of enamel, dental agenesis, and skeletal open bite.

A case of amelogenesis imperfecta with hypoplasia, hypocalcification of the enamel, congenital absence of teeth 12 and 22, delayed eruption of tooth 23, edge-to-edge incisal relationship, open bite, and bilateral posterior cross bite at the level of the first and second premolars is presented. Lateral skull teleradiography indicated a Class III skeletal pattern of maxillary origin associated with a dolichofacial pattern with multiple indicators of facial hyperdivergence. The patient presented a major esthetic abnormality of the face and required orthodontic treatment prior to a prosthetic solution with full-coverage metal-ceramic crowns in both the maxilla and the mandible. The diagnosis of cases such as this one and the therapeutic implications from an orthodontic and prosthetic standpoint are reported.

Adolescent↗
PubMed1991

Establishment of rostrocaudal polarity in tectal primordium: engrailed expression and subsequent tectal polarity.

In the E4 (embryonic day 4) chick tectal primordium, engrailed expression is strong at the caudal end and gradually weakens toward the rostral end. We used quail-chick chimeric tecta to investigate how the caudorostral gradient of engrailed expression is established and whether it is correlated with the subsequent rostrocaudal polarity of tectal development. To examine the positional value of the tectal primordium, we produced ectopic tecta in the diencephalon by transplanting a part of the mesencephalic alar plate heterotopically. In the ectopic tectum, the gradient of the engrailed expression reversed and the strength of the expression was dependent on the distance from the mes-diencephalon junction; the nearer the ectopic tectum was to the junction, the weaker the expression was. Consequently, the pattern of the engrailed expression in the host and ectopic tecta was nearly a mirror image, suggesting the existence of a repressive influence around the mes-diencephalon junction on the engrailed expression. We examined cytoarchitectonic development in the ectopic tecta, which normally proceeds in a gradient along the rostrocaudal axis; the rostral shows more advanced lamination than the caudal. In contrast, the caudal part of the ectopic tecta (near to the mes-diencephalon junction) showed more advanced lamination than the rostral. In both the host and ectopic tecta, advanced lamination was observed where the engrailed expression was repressed, and vice versa. Next we studied the correlation between engrailed expression and retinotectal projection from a view of plasticity and rigidity of rostrocaudal polarity in the tectum. We produced ectopic tecta by anisochronal transplantations between E3 host and E2 donor, and showed that there is little repressive influence at E3 around the mes-diencephalon junction. We then made chimeric double-rostral tectum (caudal half of it was replaced by rostral half of the donor tectum) or double-caudal tectum at E3. The transplants kept their original staining pattern in hosts. Consequently, the chimeric tecta showed wholly negative or positive staining of engrailed protein on the grafted side. In such tecta retinotectal projection pattern was disturbed as if the transplants retained their original position-specific characters. We propose from these heterotopic and anisochronal experiments that the engrailed expression can be a marker for subsequent rostrocaudal polarity in the tectum, both as regards cytoarchitectonic development and retinotectal projection.

Animals↗
PubMed1988

Tumour marker immunoreactivity in adenocarcinoma.

To determine whether variations in the expression of tumour related antigen can predict the origin of tumours, the immunoreactivity of a series of adenocarcinomas from a wide range of sites was studied with a panel of monoclonal antibodies with specificity for carcinoembryonic antigen, carcinoembryonic antigen with non-specific cross reacting antigen co-specificity, epithelial membrane antigen, OC 125, and OC 19.9. A range of reactivity was seen in tumours from most sites. No distinctive results were identified for a particular site of origin. Some patterns of consistent positivity or negativity for the panel of antisera used were seen, however, which if applied to metastatic deposits have the potential to assist prediction of the site of origin. These results also imply that immunohistological reactivity should be considered in the selection of a tumour marker for serological monitoring.

Adenocarcinoma↗
PubMed1996

Discrimination of forearm's motions by surface EMG signals using neural network.

We tried to discriminate different forearm's motions by surface EMG signals using neural network. In order to get a higher discrimination rate, the positions of electrodes were improved. We also tried to discriminate similar motions in order to clarify the limitation of the discrimination by surface EMG signals. Two experiments were carried out. One was to discriminate five different motions: grasp, wrist flexion, wrist extension, forearm pronation, and forearm supination (Experiment 1). The other was to discriminate four similar motions which have different quantitative definitions at grasp, wrist flexion/ extension, or forearm pronation/supination (Experiment 2). Four surface electrodes were placed on the skin above the main active muscles: short radial extensor m. of wrist, supinator m., long radial extensor m. of wrist, and ulnar flexor m. of wrist, considering anatomical functions of the forearm's muscles. EMG signals were recorded during 2 sec while the subjects kept the motions. Recorded EMG signals were sampled at 200 msec intervals after full-wave rectifying and low-pass filtering. Therefore, the number of sampling data patterns of EMG signals was 10 for every motion. Three layers of neural network was used for discrimination. The number of units in the input layer is 4, and the number of units in the output layer is 5 or 4. In order to get the best discrimination rate of the motions, we changed the number of units in the hidden layer from 3 to 12. The neural network was trained by the back-propagation algorithm. In Experiment 1, the best average values of discrimination rates under three patterns of EMG signals for each subject were 96.0%, 98.0%, and 87.2% when the numbers of units in the hidden layer were 10, 11, and 3 respectively. In Experiment 2 using original EMG patterns, the best average values of discrimination rates at grasp, extension/flexion, and pronation/supination were 59.5%, 76.0%, and 25.0% respectively. By using normalized EMG patterns, these were 40.0%, 84.8%, and 55.5% respectively.

Adult↗
PubMed2004

Classification of German white wines with certified brand of origin by multielement quantitation and pattern recognition techniques.

A procedure is proposed for the determination of the authenticity of white wines from four German wine-growing regions (Baden, Rheingau, Rheinhessen, and Pfalz) based on their content of some major, trace, and ultratrace elements. One hundred and twenty-seven white wine samples possessing a certificate of origin, all of the 2000 vintage, were analyzed. The concentrations of 13 elements (Li, B, Mg, Ca, V, Mn, Co, Fe, Zn, Rb, Sr, Cs, and Pb) were determined in wine diluted 1:20 by sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). Indium was routinely used as internal standard. Supervised pattern recognition techniques such as discriminant analysis and classification trees were applied for the interpretation of the data. A quadratic discriminant analysis (QDA) allowed the four regions to be discriminated with 83% accuracy when using only eight variables (Li, B, Mg, Fe, Zn, Sr, Cs, and Pb), and the prediction ability for classifying new samples was 76%. By use of a second method, a decision tree, the classification of samples coming from the four regions could be performed with an accuracy of 84% when only four elements were used: Li (very low in samples from Baden), Zn (abnormally low in the samples from the Rheingau), and Mg and Sr (both important for the differentiation between Pfalz and Rheinhessen samples). For this method, the prediction ability was only 74% in the identification of unknown samples. The robustness of the QDA model was not good enough, and therefore the tree is better recommended for the classification of new wine samples from these areas of German wine production.

Germany↗
PubMed2003

Coding of visual patterns and textures in monkey inferior temporal cortex.

Neural coding for texture features of visual objects was investigated in monkey inferior temporal cortex by inactivating intrinsic GABAergic inhibition. The inactivation enabled a substantial number of cells to respond to originally ineffective texture pattern that had a particular feature distinct from the originally effective pattern, or to ineffective texture and non-texture stimuli that possessed a component feature of the originally effective texture. Cells that showed selectivity changes related to a texture feature were often met along a vertical recording track. We suggest that a texture feature is coded by a group of cells which signal different aspects of the texture. The coding occurs at different processing levels, from extracting a particular feature within patterns to detecting complex texture features combined with color and shape of natural objects.

Animals↗
PubMed1992

Origin of mineral crystal growth in collagen fibrils.

Collagen fibrils from young turkey-leg tendons, just beginning to mineralize, were stained with uranyl acetate and examined by electron microscopy. Small needle-like mineral crystals were observed and located, in relation to the collagen banding pattern, as originating at the e band in the gap region and near the surface of the fibrils. These are evidently the sites of crystal nucleation. They lie near binding locations on collagen fibrils of two glycosylated proteins believed to be implicated in the mineralization process, as well as the sites of early crystals in embryonic fowl bones.

Animals↗
PubMed1994

The prevalence of hepatitis B and C in an antenatal population of various ethnic origins.

A total of 3522 samples of serum, collected anonymously from women attending an antenatal clinic, was tested for hepatitis B surface antigen and antibody to hepatitis C. The prevalence of anti-HCV was low; only five confirmed positives were found (0.14%). The prevalence of hepatitis B overall was 0.56%, but was 1.04% in women from immigrant groups. Hepatitis B carriage is therefore four times more common than hepatitis C carriage in the antenatal population comprised of various ethnic origins. The patterns of infection in the two viruses are reversed, hepatitis B being more common in Asian, S.E. Asian and West Indian mothers and hepatitis C being more common in mothers of white Caucasian origin. Routine antenatal screening for anti-HCV is discussed.

Adolescent↗
PubMed1995

Genetic analysis of dermatophilus spp. using multilocus enzyme electrophoresis.

Multilocus enzyme electrophoresis was used to examine a collection of 41 mainly Australian isolates of Dermatophilus congolensis that had been cultured from sheep, cattle, horses, a goat, a marsupial and Chelonids. Allelic variation was examined at 16 enzyme loci. The isolates were divided into eight distinct electrophoretic types (ETs) with a mean genetic diversity per locus of 0.41. The three isolates from Chelonids represented a distinct clone in ET 1 which was separated from the remaining cluster of isolates of D. congolensis by a genetic distance of 0.852. These findings supported a previous proposal that the isolates from Chelonids represent a new species of Dermatophilus. The other 38 D. congolensis isolates were separated into two divisions (I and II) by a genetic distance of 0.560. The divisions were both subdivided into groups that either only contained alpha-hemolytic or beta-hemolytic isolates, but all isolates in each ET had only one hemolytic pattern. Isolates originating from the same animal species, or from the same geographic location, were not all closely related genetically. The allocation of isolates into ETs correlated well with their distribution into DNA restriction endonuclease analysis patterns previously established for the collection. Although relatively few distinct strains of D. congolensis were identified amongst the collection, significant genetic diversity existed within this population.

Actinomycetales↗
PubMed2005

ATPase-dependent cooperative binding of ORC and Cdc6 to origin DNA.

Binding of Cdc6 to the origin recognition complex (ORC) is a key step in the assembly of a pre-replication complex (pre-RC) at origins of DNA replication. ORC recognizes specific origin DNA sequences in an ATP-dependent manner. Here we demonstrate cooperative binding of Saccharomyces cerevisiae Cdc6 to ORC on DNA in an ATP-dependent manner, which induces a change in the pattern of origin binding that requires the Orc1 ATPase. The reaction is blocked by specific origin mutations that do not interfere with the interaction between ORC and DNA. Single-particle reconstruction of electron microscopic images shows that the ORC-Cdc6 complex forms a ring-shaped structure with dimensions similar to those of the ring-shaped MCM helicase. The ORC-Cdc6 structure is predicted to contain six AAA+ subunits, analogous to other ATP-dependent protein machines. We suggest that Cdc6 and origin DNA activate a molecular switch in ORC that contributes to pre-RC assembly.

Amino Acid Sequence↗
PubMed1992

[Disease patterns during the first year in the arctic mining industry].

In the zinc, lead and silver ore mine of Maarmorilik, Greenland 1,061 episodes of illness in the first year of employment were studied in 421 persons. Despite the fact that about 80% of the employees were of Scandinavian origin, the patterns of illness were considerably different from the health problems in primary health care units in Denmark. Urogenital problems were the only group of illnesses representing overweight of multiple contact episodes. All other groups of diagnoses were dominated by episodes of single contact. Dental problems, traumatic and urogenital episodes appeared more frequently compared to Danish primary health care units. The lower frequency of traumatic episodes in women reflected their employment in service jobs only. Despite a health examination before employment the total amount of episodes of illness corresponded to that of primary health care units in Denmark, and the age specific contact rate for males was higher than in other morbidity studies from Greenland. Possible explanations were: sick leave required documentation of the doctor, the workload was heavy and prolonged, the spare time possibilities were few, the buildings were inadequate, the employees were isolated from their families for months and the consumption of alcohol was considerable. Because the doctor was the only person with health education in the mining village, knowledge about dental treatment and considerable experience in traumatology and diagnosis of venereal disease were necessary.

Arctic Regions↗
PubMed1999

Locomotor and feeding activity rhythms in a light-entrained diurnal rodent, Octodon degus.

The wheel running (WR) and feeding activity (FA) of Octodon degus, a new laboratory rodent characterized by its diurnal habits, were recorded under different lighting conditions. Under 12:12-h light-dark (LD 12:12) cycles, WR activity exhibited a crepuscular pattern with two peaks, M and E, associated with "dawn" and "dusk," respectively. In both cases, an anticipatory activity was patent, suggesting that, beside the masking effect of LD transitions, both peaks have an endogenous origin. This pattern, which was also observed under a skeleton photoperiod (LD 0.5:11.5), became unimodal after LD 0.5:23.5 and constant darkness (DD) exposure. Simultaneously, FA showed an arrhythmic pattern in most animals, especially under DD, when none of the animals exhibited a significant circadian rhythm. The existence of two groups of oscillators, or two oscillators, would explain most properties of the WR rhythms noted in this species. Our results show that the degu's temporal feeding strategy seems mainly arrhythmic, whereas its WR pattern is driven by a strongly circadian bimodal rhythm.

Animals↗