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At least 91 records · Page 5Linked to original sources
PubMed1986

Suppression-burst pattern associated with generalized epileptiform discharges and alpha-theta pattern coma.

In this paper we reported a patient with multisystem failure, whose EEG immediately preceding death demonstrated a unique combination of suppression-burst pattern, generalized epileptiform discharges, and alpha-theta pattern coma. Post-mortem examination showed ischemic-anoxic lesions involving cortical and sub-cortical gray matter. The lack of white matter pathology in our patient indicates that white matter lesions may not be involved in the pathogenesis of the above EEG patterns in anoxic encephalopathy.

Aged↗
PubMed1986

Diagnostic significance of nailfold capillary patterns in patients with Raynaud's phenomenon. An analysis of patterns discriminating patients with and without connective tissue disease.

Nailfold capillary patterns were systematically evaluated in 51 controls and 107 patients with Raynaud's phenomenon (RP) by 2 observers. Fifty patients had primary RP, 18 RP with minor signs of connective tissue disease, and 39 secondary RP (scleroderma, CREST syndrome or mixed connective tissue disease [MCTD]). Nailfolds of all 10 fingers were photographed and blindly evaluated. Qualitative and quantitative scoring of patterns was reproducible. The 4th finger showed the fewest nonevaluable photomicrographs and best distinguished primary from secondary RP. Capillary morphology in primary RP did not differ from controls. A decrease in capillary loops best distinguished primary from secondary RP. Addition of the scores for bushy patterns, extravasates, or giant loops led to better discrimination. No item allowed distinction between different connective tissue diseases. The number of enlarged loops was inversely related to the total number of capillary loops (r = 0.55; p less than 0.01).

Adult↗
PubMed1985

Dynamics of the control of body pattern in the development of Xenopus laevis. II. Timing and pattern in the development of single blastomeres (presumptive lateral halves) isolated at the 2-cell stage.

Xenopus embryos have been selected in which the first cleavage plane is tending strongly to correspond with that of bilateral symmetry for the future larval pattern. The two blastomeres produced by this cleavage have been separated and allowed to develop as reciprocal pairs of presumptive lateral-half isolates. The early development and the time course of the gastrulation movements, and the qualitative and quantitative aspects of larval mesodermal patterns, have been studied in relation to synchronously fertilized controls. The result is restoration of bilateral symmetry for developmental potential, and production of a pair of small gastrulae and larvae with qualitatively complete body plans but 50% of control cell numbers each (see Kageura & Yamana, 1983). Most commonly, however, the resulting small patterns deviate from the normal range in their proportions in at least one of two ways. The notochord territory is rarely, if ever, under-represented (i.e. notochords contain at least 50% control cell numbers) but it is frequently over-represented, in some cases approximating that of control whole embryos. Reciprocal pairs of isolates thus tend, on average, to produce more notochordal tissue than they would have if developing normally. Secondly, the balance of cell population sizes assigned to somites up and down the axis is altered so that relatively anterior members of the series are less scaled down than those in trunk and tail regions. The mesodermal plan developed by a lateral-half isolate is thus characteristically intermediate between that of a small, harmonious larva (the proportional presumptive fates of the materials, apart from loss of bilaterality), and that of the mosaically developing presumptive dorsoanterior cell pair from the 4-cell stage, discussed in the previous paper. A minority of the lateral isolates does develop a harmonious and thus well-regulated body plan, however, and the normality or otherwise of the schedules of gastrulation timing in isolates seems a good predictor of their morphogenetic performance in this respect. The results are discussed as informing us about the dynamics of the interactions, prior to gastrular stages, that underlie the normal mesoderm development.

Animals↗
PubMed1989

Pattern visual evoked potentials and pattern electroretinograms in hypothyroidism.

This study reports the pattern visual evoked potential (PVEP) findings in 10 patients with idiopathic hypothyroidism. Eight of these patients also had pattern electroretinography (PERG) performed and six were additionally seen after treatment with thyroxine. Only one patient had definitely abnormal PVEPs at the time of initial recording. PERGs at this time were of abnormal latency and subnormal amplitude. Following treatment with thyroxine the patient became euthyroid. Repeat electrodiagnostic testing now showed both PERGs and PVEPs within the normal range, having markedly improved in both latency and amplitude. This suggests that the PVEP delay was probably secondary to reversible central retinal dysfunction.

Electroretinography↗
PubMed1989

Effect of levodopa on the human pattern electroretinogram and pattern visual evoked potentials.

Pattern electroretinograms (P-ERGs) and pattern visual evoked potentials (P-VEPs) were recorded at three luminance levels and five different check sizes in a group of 16 control subjects before and after the oral administration of levodopa. At the lower luminance levels, significant decrease in P-ERG and P-VEP latencies were found. For P-VEPs the latency changes occurred only at small check sizes. No changes were observed in control experiments without levodopa administration. Our results show that levodopa-induced changes even occur at the retinal level and support a dopaminergic involvement in light and dark adaptation. Our observations are in agreement with a VEP delay found in Parkinson's disease and with a VEP latency increase in rats after dopamine depletion.

Administration, Oral↗
PubMed1990

The effect of various anaesthetics on the spatial tuning of two major wave peaks in the transient pattern electroretinogram of the cat: evidence for pattern and luminance components.

The main PERG component of the transient contrast reversal pattern electroretinogram (PERG) in cats was a negative wave (3.5 microV average, SD 1.7 microV) peaking at about 130 msec (N130) with a spatial resolution above 5.5 c/deg, close to behavioural estimates. The early positivity (P35) was more variable, smaller and had lower spatial resolution. Different anaesthetic protocols affected both the waveform and the amplitude by spatial frequency functions. Responses of urethane anaesthetised cats were like those reported previously for decerebrate cats or cats paralysed and ventilated with N2O/O2/CO2 (75%/24%/1%). P35 was evoked only by coarse stimuli and N130 amplitude decreased linearly as spatial frequency increased. When the luminance response amplitude, predicted from the optical transfer function of the eye, was subtracted, spatial tuning appeared. An anaesthetic mixture of ketamine hydrochloride and xylazine depressed both P35 and N130 at low spatial frequencies while enhancing them at high frequencies. In paralysed animals ventilated with N2O/O2 (67%/33%) P35 was larger and recordable to 1.6 c/deg. Peak times were reduced and the inter-peak time halved. Other anaesthetics depressed the ERGs. These effects suggest that cats are a good model for studying N130 in isolation or its interaction with P35 and that both PERG peaks include luminance and pattern components.

Anesthetics↗
PubMed1988

Investigation of the geographical distribution of female cancer patterns in Belgium using pattern recognition techniques.

Different multivariate methods have been applied to obtain an overview of the Belgian female cancer mortality distribution. The resulting maps and figures show the patterns of female cancer mortality to be strongly geographically determined. Two major trends can be derived namely along the north-south axis and along the east-west axis of the country. The cancer sites responsible for these patterns are identified.

Belgium↗
PubMed1991

Quantitative analysis of the cross-correlation between pattern ERG and pattern VEP.

The cross-correlation between PVEPs and PERG was investigated. (1) There were high correlations between PVEPs recorded from the inion and those from points Oz, Pz, Cz, and Fz in the range of 75-150 msec following pattern visual stimulation to the eyes although no correlation was found in the range 0-75 msec. (2) PVEPs recorded from the inion highly correlated with PERG in the 75-150 msec range but not in the 0-75 msec range. It suggests that the late negative component included in the PERG reflected the electrotonically spread at the eye level of PVEP. (3) Intra-individual reproducibility was studied. PVEPs showed a high reproducibility in the 75-150 msec range, but not in the 0-75 msec range. The reproducibility of PERG was high in the 0-75 msec range but also in the 75-150 msec range, where PERG reflected PVEPs. These results suggest that the early positive component of PERG was specific to the cell activities in the retina to the pattern visual stimulus, and had an origin different from the brain activity for PVEPs.

Adult↗
PubMed1989

[Pattern electroretinography and pattern visual evoked potentials in maculopathy: a comparison with sensory tests].

The retinal and cortical potentials for pattern reversal were recorded in 58 eyes of 30 patients afflicted with macular disease. The highest incidence of abnormality (79%) was found for the amplitudes P-ERG and P-VECP. Total field EOG and L-ERG were affected less frequently (41% and 25%). The P-ERG amplitude correlated significantly with the sensitivity of the central 10 degrees visual field (static perimetry). The P-VECP threshold check size showed a close correlation with visual acuity. Thus, the recording of pattern-evoked retinal and cortical potentials serves as a supplementary means of assessing types of maculopathy.

Adolescent↗
PubMed1990

Identification of protein folds: matching hydrophobicity patterns of sequence sets with solvent accessibility patterns of known structures.

Hydrophobic side chains often are buried in the interior of a protein, and evolutionarily related proteins usually maintain the hydrophobic character of buried positions. In this paper we show that a pattern of hydrophobicity values derived from a set of related protein sequences is well correlated with the linear pattern of side-chain solvent accessibility values, calculated from a known protein structure representative of the sequences. In several cases, information from aligned sequences can be used to select the correct tertiary fold from a large data base of protein structures.

Algorithms↗
PubMed1992

Flow patterns of blood cells in the retinal capillaries. Retinal capillary flow patterns.

We present a new technique for retinal blood cell angiography which was used to investigate flow patterns of blood cells in the retinal capillary net of normal cats. Capillary paths were defined to be the path taken by the labelled blood cells from the terminal arteriole to the entry point into a collecting venule. We were able to define two types of capillary paths. The 'simple' paths were minimally coiled and had a high blood cell flux. The 'complex' paths were coiled, structurally complex and had a low blood cell flux in comparison to the simple paths of the same eye. A simultaneous fluorescein angiogram was performed to reveal the complete anatomy of the capillary net in which the functional paths exist. The possibility that such flow patterns exist in the human retina should be considered.

Animals↗
PubMed1992

Properties of favored patterns in spontaneous spike trains and responses of favored patterns to electroacupuncture in evoked trains.

By using 'the modified detection method', our previous study has shown that all spontaneous spike trains recorded from several areas of brain and spinal cord have favored patterns (FPs). The present study further shows that: (1) all newly detected spike trains from substantia nigra zona compacta, nucleus periventricularis hypothalami and nucleus hypothalamicus posterior also have FPs, and some spike trains from neurons in the same nucleus have a common favored pattern (CF, i.e. they share the same FP), indicating that FP and CF in spike trains are common phenomena; (2) all serial correlation coefficients of FP repetitions (in serial order) in different spike trains detected are less than 0.3 (close to 0), revealing that the repetition of FPs is a renewal process; (3) in different periods of the spike trains evoked by electroacupuncture (EA), the number of different FPs and the number of repetitions of the same representative FP either increase or decrease along with the change of firing rate. The tendencies of these changes are very similar, but after EA the repetitions of different FPs in the same spike trains change differently, showing that different (hidden) responses exist at the same time. The above results suggest that the FPs in spike trains may represent various neural codes, and 'the modified detection method of FP' can pick up more information from spike trains than the firing rate analysis, hence it is a very useful tool for the study of neural coding.

Animals↗
PubMed1985

S-phase patterns of cyclin (PCNA) antigen staining resemble topographical patterns of DNA synthesis. A role for cyclin in DNA replication?

The sequence of cyclin (proliferating cell nuclear antigen, PCNA), antigen staining throughout the cell cycle of African green monkey kidney cells (BS-C-1) has been determined by indirect immunofluorescence using PCNA autoantibodies specific for this protein. Patterns of cyclin staining observed between the beginning of S-phase and maximum DNA synthesis are similar to those reported in human AMA cells [(1985) Proc. Natl. Acad. Sci. USA 82, 3262-3266], while those detected thereafter are significantly different; the most striking feature being the continuous staining of the nucleoli up to or very near the S/G2 border of the cell cycle. Using [3H]thymidine autoradiography and indirect immunofluorescence of the same cells we show a remarkable correlation between cyclin antigen distribution and topographical patterns of DNA synthesis. In addition, we present evidence showing that DNase I treatment of Triton-extracted monolayers abolishes cyclin antigen staining but does not result in a substantial release of this protein. Taken together the above observations argue for a role of cyclin in some aspect of DNA replication.

Animals↗
PubMed1989

Different homing pattern of isolated mouse lymphoma cells correlates with a different chromosomal pattern.

After 5-20 weeks of in vitro culture of mouse lymphoma cells, a characteristic and reproducible change in cell morphology, clonogenic ability, and homing pattern after intraperitoneal or intravenous injection was observed. Cytogenetic comparison of the two cell populations present before and after the "switch" revealed that the phenotypic changes cannot be due to in vitro karyotype evolution because their chromosomal pattern differed in such a way that it is impossible that they can evolve from each other. It was concluded that two different cell populations are present in the lymphoma and their growth and behavior are influenced by certain circumstances and/or interactions. Apparently one population predominates in the peripheral blood circulation, whereas the other will predominate after prolonged in vitro culturing.

Animals↗
PubMed1992

Recent patterns of growth in radiation therapy facilities in the United States: a patterns of care study report.

The Patterns of Care Study conducted its seventh survey of radiation oncology facilities with megavoltage equipment. The aims were to identify the basic structural characteristics of the radiation oncology specialty, to allow comparison with previous surveys, to identify trends in the patterns of equipment and personnel usage, and to measure the capabilities of facilities to deliver modern radiotherapy. All radiation oncology facilities in the United States and Puerto Rico were surveyed. Multiple mailings and calls yielded identification of and responses from virtually all facilities doing megavoltage radiotherapy. The survey collected information on equipment, patient load, personnel, and types of procedures performed. The complete census was reviewed, summarized, and compared to previous surveys. Results for 1990 showed 1321 facilities, (938 hospital based, 350 freestanding, 33 federal), 492120 new patients, and 2397 treatment machines (1893 linear accelerators or betatrons and 504 cobalt machines). The number of facilities and total machines increased rapidly with most of the increase in facilities occurring in the freestanding category. The number of cobalt units declined, while the number of linear accelerators increased. The results also showed that 6% of facilities did not have the capability of simulating patients and 7% of facilities did not have treatment planning capability. Of all facilities 9% reported doing intraoperative radiation therapy and 18% doing hyperthermia. For recent years in the specialty of radiation oncology the number of facilities and treatment machines increased at a more rapid rate than the number of new patients.

Health Facilities↗
PubMed1988

Associative neural network model for the generation of temporal patterns. Theory and application to central pattern generators.

Cyclic patterns of motor neuron activity are involved in the production of many rhythmic movements, such as walking, swimming, and scratching. These movements are controlled by neural circuits referred to as central pattern generators (CPGs). Some of these circuits function in the absence of both internal pacemakers and external feedback. We describe an associative neural network model whose dynamic behavior is similar to that of CPGs. The theory predicts the strength of all possible connections between pairs of neurons on the basis of the outputs of the CPG. It also allows the mean operating levels of the neurons to be deduced from the measured synaptic strengths between the pairs of neurons. We apply our theory to the CPG controlling escape swimming in the mollusk Tritonia diomedea. The basic rhythmic behavior is shown to be consistent with a simplified model that approximates neurons as threshold units and slow synaptic responses as elementary time delays. The model we describe may have relevance to other fixed action behaviors, as well as to the learning, recall, and recognition of temporally ordered information.

Animals↗
PubMed1982

[The radiological examination of the detailed relief pattern of the stomach part 4 (direct comparison of the pattern in the pyloric canal with the histological findings as related to the problem of chronic gastritis) (author's transl)].

Following earlier work on the relationship between the micromucosal pattern of the stomach and chronic gastritis, a comparison was carried out between the appearances in the pyloric canal and the histological findings in that area. The presence of chronic gastritis could not be excluded, irrespective of the type of relief pattern. Normal gastric mucosa was only found in areas showing medium sized areae gastricae. Fundamental problems concerning the radiological technique are discussed as well as the evidence for the diagnosis of chronic gastritis.

Adult↗