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PubMed1986

Effect of skeleton photoperiod and food availability on the circadian pattern of feeding and drinking in rats.

Feeding and drinking behavior were measured in rats maintained under a 12:12 light-dark (LD) cycle or skeleton photoperiod (SPP). Feeding and drinking were closely associated during the normal LD cycle but under SPP conditions an increased feeding activity during the subjective day was not accompanied by an equivalent increment of water intake. This indicates a stronger coupling of drinking to the subjective night. A restriction of food availability to the subjective light phase did not cause an accompanying complete shift in drinking behavior. These results suggest that drinking is largely dependent on the influence of a circadian oscillator and this association is not disrupted by changes in feeding schedule. A change in food access to the subjective light phase caused partial but not permanent desynchronization between feeding and drinking behavior. Synchrony was reestablished within one day once food was available ad lib. Complete return to the original feeding and drinking patterning took 3 days. It is suggested that separate slave oscillators controlling feeding and drinking are governed by a hypothesized "master" circadian oscillator which remains definitely entrained to the original rhythm by the light pulses of the SPP condition.

Animals↗
PubMed1995

Morphological fate of rhombomeres in quail/chick chimeras: a segmental analysis of hindbrain nuclei.

Quail rhombomeres two to six (r2-r6) were individually grafted homotopically into the hindbrain of chick embryos at 2 days of incubation. Nine to 10 days after the operation the chimeric embryos were fixed and processed for parallel cytoarchitectural and immunocytochemical study (with an anti-quail antibody) in order to map the anatomical fate of the grafted tissue. Emphasis was placed on conventionally identified and distinct neuronal populations composing the sensory and motor longitudinal columns. Grafted rhombomeres consistently developed as complete transverse slices of the chimeric hindbrain. Interrhombomeric cell migration was either sparse or restricted to specific nuclei. The cranial nerve motor nuclei showed rhombomeric origins consistent with the patterns described in early embryos. Unexpectedly, alar r2 was found to form the auricular part of the cerebellum. As regards the cochlear nuclei, we found that nucleus angularis derives from r3 to r6, nucleus laminaris from r5 to r6, nucleus magnocellularis from r6 to r7 and nucleus olivaris superior from r5. The nuclei of the lateral lemniscus originated between r1 and r3. We also delimited the respective rhombomeric subdivisions of the sensory vestibular and trigeminal columns, both of which extend from r1 caudalwards throughout the hindbrain. There were consistently some interrhombomeric neuronal migrations inside the vestibular column, some motor nuclei and the reticular formation, involving only one rhombomere length. The pontine nuclei, which extended from r1 to r7, showed neuronal migrations that crossed several rhombomeres. On the whole, these results represent the first anatomical analysis of the mature avian hindbrain in terms of rhombomere-derived domains.

Animals↗
PubMed1996

Subsequent breast carcinoma risk after biopsy with atypia in a breast papilloma.

BACKGROUND: Risk of breast cancer after biopsy demonstrating a papilloma has long been variously interpreted on the basis of histologic pattern of multiplicity of papillomas. METHODS: A nested case control study was performed on women with surgical breast biopsies evidencing papillomas; cases who subsequently developed invasive carcinoma were compared with controls who did not. Presence of atypical hyperplasia (AH) within the papilloma as well as areas of AH in the surrounding parenchyma were evaluated in both cases and controls. The entire cohort (not tested) was separately evaluated for all variables except for atypia within papillomas. RESULTS: The relative risk of invasive carcinoma for women with papillomas containing AH was > 4x that of papillomas without AH within or surrounding the papilloma. This risk may be greater with added atypical hyperplasia outside the papilloma and most strikingly, most of the subsequent invasive carcinomas developed in the same breast and probably near the site of the original papilloma. However, ordinary patterns of epithelial hyperplasia lacking specific features of AH within the papilloma do not add to the risk of subsequent carcinoma development over papillomas without hyperplasia. CONCLUSIONS: This study indicates that women having papillomas with AH have a similar or greater cancer risk than others with specifically defined patterns of atypical hyperplasia within the breast parenchyma (4-5x relative risk). Most importantly, this risk is largely local in the region of the original papilloma.

Adult↗
PubMed2006

Resonance tuning in a neuro-musculo-skeletal model of the forearm.

In rhythmic movements, humans activate their muscles in a robust and energy efficient way. These activation patterns are oscillatory and seem to originate from neural networks in the spinal cord, called central pattern generators (CPGs). Evidence for the existence of CPGs was found for instance in lampreys, cats and rats. There are indications that CPGs exist in humans as well, but this is not proven yet. Energy efficiency is achieved by resonance tuning: the central nervous system is able to tune into the resonance frequency of the limb, which is determined by the local reflex gains. The goal of this study is to investigate if the existence of a CPG in the human spine can explain the resonance tuning behavior, observed in human rhythmic limb movement. A neuro-musculo-skeletal model of the forearm is proposed, in which a CPG is organized in parallel to the local reflexloop. The afferent and efferent connections to the CPG are based on clues about the organization of the CPG, found in literature. The model is kept as simple as possible (i.e., lumped muscle models, groups of neurons are lumped into half-centers, simple reflex model), but incorporates enough of the essential dynamics to explain behavior-such as resonance tuning-in a qualitative way. Resonance tuning is achieved above, at and below the endogenous frequency of the CPG in a highly non-linear neuro- musculo-skeletal model. Afferent feedback of muscle lengthening to the CPG is necessary to accomplish resonance tuning above the endogenous frequency of the CPG, while feedback of muscle velocity is necessary to compensate for the phase lag, caused by the time delay in the loop coupling the limb to the CPG. This afferent feedback of muscle lengthening and velocity represents the Ia and II fibers, which-according to literature-is the input to the CPG. An internal process of the CPG, which integrates the delayed muscle lengthening and feeds it to the half-center model, provides resonance tuning below the endogenous frequency. Increased co-contraction makes higher movement frequencies possible. This agrees with studies of rhythmic forearm movements, which have shown that co-contraction increases with movement frequency. Robustness against force perturbations originates mainly from the CPG and the local reflex loop. The CPG delivers an increasing part of the necessary muscle activation for increasing perturbation size. As far as we know, the proposed neuro-musculo-skeletal model is the first that explains the observed resonance tuning in human rhythmic limb movement.

Central Nervous System↗
PubMed2006

Fever of unknown origin: a systematic review of the literature for 1995-2004.

BACKGROUND: Fever of unknown origin (FUO) identifies a pattern of fever with temperature higher than 38.3 degrees C on several occasions over more than 3 weeks, in which the diagnosis remains uncertain after an initial diagnostic work-up. The identification of the cause of FUO is a challenge in clinical practice despite recent advances in diagnostic techniques. There are more than 200 reported causes of FUO and they can be classified in four diagnostic categories: infections, neoplasms, non-infectious inflammatory diseases and miscellaneous. METHODS: We performed a systematic research of the literature on classical FUO to retrieve the review articles and case series published from 1995 to 2004, including articles from developing countries. The case series were reviewed to identify the tests commonly used both to qualify a fever as FUO and to determine the cause of the FUO, and to design an updated flow chart for the diagnosis of classical FUO. RESULTS AND CONCLUSIONS: No standardized diagnostic strategy could be determined. The diagnostic process should be guided by the potential diagnostic clues (PDCs) emerging from the history, physical examination and baseline tests. A standardized flow chart can be applied only in absence of PDCs or when the PDCs are contradictory.Nuclear medicine techniques are a valuable aid in the search for the origin of FUO due to bacterial infections or in the absence of PDCs.

Algorithms↗
PubMed1976

Increases in collateral axonal growth rostral to a thoracic hemisection in neonatal and weanling rat.

The spinal cords of newborn and weanling rats were hemisected at the mid-thoracic level. Control studies revealed that Fink-Heimer positive debris was absent in the gray matter at three months postoperative. The remaining animals were given a second lesion, a high cervical spinal hemisection, at five to seven months after the original thoracic hemisection. The pattern of degeneration rostal to the thoracic lesion was compared with similar regions of the spinal cord from animals receiving only a cervical hemisection at the adult stage. In neither experimental group of doubly hemisected rats was there any degeneration observed below the thoracic lesion site, even though no glial or connective tissue scar had formed in animals originally operated at birth. Thus no regeneration had occurred. At least one segment above the initial hemisection: 1. the majority of degenerating axons were localized toward the lateral edge of the spinal cord, especially in the doubly lesioned neonatal group; 2. the erae of ipsilateral white matter was reduced more in the neonatal than the weanling operates; 3. there was an upward shift in axonal diameter of ipsilateral fibers in both the region of the rubrospinal tract and the ventrolateral portion of the lateral funiculus of the doubly hemisected rats when compared with the cervically lesioned controls; 4. a significantly greater amount of degeneration was present in lamina VII of Rexed in both the neonatal and weanling experimental operates (p less than 0.05 weanling; p less than 0.001 neonate); 5. no mean difference in area was seen between the ipsilateral and contralateral gray matter in any group for the segments of the spinal cord in which the judgements and measurements were taken. These data suggest that there has been sprouting of axons from descending nerve tracts rostral to the thoracic lesion in both the neonatal and weanling experimental groups. The question remains whether the sprouting of descending nerve tracts is from collateral of axons which normally project rostral to the thoracic hemisection and are not cut by the thoracic lesion (collateral sprouting) or from collaterals of lesioned axons (regenerative sprouting). Present evidence favors collateral sprouting, expecially in the neonatal operate where much retrograde cell death appears to have taken place.

Age Factors↗
PubMed1995

Genetic transformation of the synaptic pattern of a motoneuron class in Caenorhabditis elegans.

Caenorhabditis elegans possesses two classes of inhibitory locomotory neurons, the DD and VD motoneurons (mns), and they form complementary components of a cross-inhibitory neuronal network innervating dorsal and ventral body muscles. The DD and VD mns (collectively called the D mns) share a number of morphological and neurochemical features, and mutations in a number of different genes disrupt both cell types in identical ways; however, the DD and VD mns have different lineal origins and different synaptic patterns. Given the number of phenotypic features shared by the D mns, it was of interest to determine what is responsible for the synaptic patterns that distinguish them. An analysis of the locomotory defect along with a genetic epistasis test suggested that unc-55 mutations alter the function of the VD but not the DD mns. Correlated with the defective locomotory behavior of unc-55 mutants was an alteration in the distribution of varicosities, structures associated with presynaptic elements, on the VD mns. The pattern of varicosities of the unc-55 VD mns resembled that of the wild-type DD mns. Moreover, the selective removal of the DD mns revealed that unc-55 VD mns had adopted a functional role appropriate for the DD mns. Thus, unc-55 appears to be involved in producing the synaptic patterns that distinguish the two D mn classes from one another; when the gene is mutated the VD and DD mns become structurally similar and functionally equivalent.

Animals↗
PubMed1998

An in situ cytochemical evaluation of blood-brain barrier sodium, potassium-activated adenosine triphosphatase polarity.

It is presently believed that sodium, potassium-activated adenosine triphosphatase (Na+, K+-ATPase) is localized on the abluminal plasma membrane of brain endothelial cells. But there have been contrary reports from some cytochemical studies. We examined the localization of the enzyme in rat cerebral microvessel endothelium using the in situ model originally employed to establish the abluminal polarity concept. Alterations in fixation and incubation media from the original reports were conducted to determine the effect on localization pattern. With the Ernst indirect incubation method as originally used, three types of localization patterns were obtained: abluminal only, luminal only, and on both surfaces of endothelial cells. With the direct incubation method of Mayahara, reaction product was seen on both surfaces. Reduction in fixation time followed by the use of the indirect incubation method resulted in a complete loss of the reaction product. The same reduction in fixation time followed by the use of the direct method did not alter the localization pattern of the enzyme. Our results demonstrated that Na+, K+-ATPase is localized on both surfaces of brain endothelial cells. The localization pattern of Na+, K+-ATPase is significantly dependent upon fixation and the incubation medium used in the in situ model. Data discrepancies for the enzyme as reported in the literature appear to be caused by differences in cytochemical protocols, rather than the biological reasons advocated by other investigators. We conclude that past cytochemical reports of blood-brain barrier (BBB) Na+, K+-ATPase abluminal localization were incomplete. The currently held abluminal polarity theory of the enzyme needs to be reexamined. Past basic and clinical cytochemical studies of BBB Na+, K+-ATPase should be viewed and interpreted with caution.

Animals↗
PubMed2006

Genetic structure of Africanized honeybee populations (Apis mellifera L.) from Brazil and Uruguay viewed through mitochondrial DNA COI-COII patterns.

Mitochondrial genotypes of Africanized honeybees from Brazil and Uruguay were surveyed by DraI restriction of the COI-COII region. Eleven mitotypes were found, three of which had not previously been described (A28-A30). Out of 775 samples (725 from Brazil, 50 from Uruguay), 197 were A1 and 520 were A4. A1 frequency increases toward the north of Brazil, whereas A4 frequency increases toward the south, a pattern echoing the African distribution. The origin of the A4 and most of the A1 African patterns can be attributed to the introduction of Apis mellifera scutellata into Brazil in 1956. The A29 and A30 patterns have the P1 sequence observed in many Iberian Peninsula samples, which represent the traces of the introductions into Brazil and Uruguay by settlers.

Africa↗
PubMed2001

Replication intermediate analysis confirms that chromosomal replication origin initiates from an unusual intergenic region in Caulobacter crescentus.

The alpha-proteobacterium Caulobacter crescentus possesses a developmental cell cycle that restricts chromosome replication to a stalked cell type. The proposed C.crescentus chromosome replication origin (Cori) lies between hemE and RP001, an unusual intergenic region not previously associated with bacterial replication origins, although a similar genomic arrangement is also present at the putative replication origin in the related bacterium Rickettsia prowazekii. The cloned Cori supports autonomous plasmid replication selectively in the stalked cell type implying that replication of the entire chromosome also initiates between hemE and RP001. To confirm this location, we applied the 2-D (N/N) agarose gel electrophoresis technique to resolve and identify chromosome replication intermediates throughout a 30 kb region spanning Cori. Replication initiation in Cori was uniquely characterized by an 'origin bubble and Y-arc' pattern and this observation was supported by simple replication fork 'Y-arc' patterns that characterized the regions flanking Cori. These replication forks originated bi-directionally from within Cori as determined by the fork direction assay. Therefore, chromosomal replication initiates from the unusual hemE/RP001 intergenic region that we propose represents a new class of replication origins.

Blotting, Southern↗
PubMed2006

Computer-generated holograms of a real three-dimensional object based on stereoscopic video images.

A novel method of using stereoscopic video images to synthesize the computer-generated hologram (CGH) patterns of a real 3D object is proposed. Stereoscopic video images of a real 3D object are captured by a 3D camera system. Disparity maps between the captured stereo image pairs are estimated and from these estimated maps the depth data for each pixel of the object can be extracted on a frame basis. By using these depth data and original color images, hologram patterns of a real object can be computationally generated. In experiments, stereoscopic video images of a real 3D object, a wooden rhinoceros doll, are captured by using the Wasol 3D adapter system and its depth data are extracted from them. Then, CGH patterns of 1280 pixels x 1024 pixels are generated with these depth-annotated images of the wooden rhinoceros doll, and the CGH patterns are experimentally displayed via a holographic display system.

Journal Article↗
PubMed2001

Evaluation of genetic diversity of poplar genotypes by RAPD and AP-PCR analysis.

RAPD (randomly amplified polymorphic DNA) and AP-PCR (arbitrarily primed PCR) were utilized to establish the genetic diversity of 19 Populus genotypes. A set of 40 primers of random sequence was tested, of which 35 exhibited polymorphism. Eighteen primers generated 162 easily detectable bands between 250 and 2,500 base pairs in size, sufficient to distinguish between the genotypes. Similarity measures, cluster and multidimensional scaling analysis were performed to evaluate the RAPD and AP-PCR data. Our study demonstrated that in most instances similarity in the RAPD and AP-PCR banding patterns reflected the relationship due to origin. Nineteen primers gave a species or hybrid-specific pattern. One primer generated a specific pattern in P. euramericana. Ten primers produced specific fragments in VIF (P. alba), 4 primers in KOR (P. pyramidialis x P. berolinensis) and 4 primers in UNA and RAS (P. trichocarpa x P. deltoides). The results of this study demonstrated that RAPD or AP-PCR can be used to distinguish between poplar genotypes.

Genetic Variation↗
PubMed1984

DNA methylation versus gene expression.

Vertebrate DNA is methylated at a high proportion of cytosine residues in the sequence CpG, and it has been suggested that the distribution of methylated and non-methylated CpGs in a given cell type influences the pattern of gene expression in those cells. Since a DNA methylation pattern is normally transmitted faithfully to daughter cells via cell division, this idea suggests an origin for stable, clonally inherited patterns of gene expression. This article discusses some of the current evidence for a relationship between DNA methylation and gene expression. Although the evidence is incomplete, it appears already that the relationship is variable: transcription of some genes is repressed by the presence of 5-methylcytosine at certain CpGs, and may be controlled by methylation, while transcription of other genes is indifferent to methylation. In attempting to explain this variability it is helpful to adopt an evolutionary perspective.

5-Methylcytosine↗
PubMed1980

Antiquity of the vertebrate pattern of activity metabolism and its possible relation to vertebrate origins.

Vertebrates generally possess well developed capacities for anaerobic metabolism, resulting in formation of lactic acid. Those capacities have traditionally been interpreted in terms of adaptation to hypoxic environments or to special situations such as diving. However, anaerobic metabolsim in striated muscle tissue is frequently a major source of ATP utilized during periods of intense activity. The evolutionary significance of anaerobically supported activity has not been discussed, although the interrelationships of capacities for aerobiosis and activity have received considerable attention. We present here evidence that the pattern of activity metabolism utilized by extant species probably dates back to the earliest vertebrates. It is also postulated that the evolution of extensive capacity for anaerobically supported burst activity may have been closely related to the evolution of vertebrates from invertebrate chordates.

Aerobiosis↗
PubMed2006

[Comparison of the antibiotics sensibility pattern of Listeria monocytogenes and Salmonella spp. strains isolated from food with clinical origin samples].

The actual use of antibiotics includes, not just its therapeutic cases, but also for disease prevention and as a growth promoter in animals. These practices have resulted in the propagation of resistance to antibiotics, representing a threat for Public Health. In this work, the antibiotic sensibility pattern of 20 Listeria monocytogenes and 40 Salmonella spp. strains, isolated from foodstuff was studied and compared with the antibiotic sensibility patterns of 20 L. monocytogenes and 100 Salmonella strains of clinical origin. 95% of the L. monocytogenes strains isolated from food were sensible to ampicillin, compared with the 65% of the clinical origin strains. Same way, 100% of food strains were sensible to gentamicin, compared with 85% of clinical origin strains. 95% of both showed sensibility to trimethoprim sulfametoxazole and 100% to ciprofloxacin. For Salmonella spp., the sensibility patterns for trimethoprim sulfametoxazole, gentamicin, ciprofloxacin, nalidixic acid and amoxicilin/clavulanic acid from both origins were similar. Nevertheless, food origin strains showed a 97.5% and 82.5% sensibility for tetracycline and cephalosporin respectively, compared with a 83 and 90% sensibility shown by clinical origin strains. The results obtained demonstrate the potential risk that bacterial strains isolated from food represent in the transmission of antibiotics' resistance.

Amoxicillin↗
PubMed1993

The effect of optical defocus on the pattern electroretinogram in normal subjects and patients with Alzheimer's disease.

The pattern electroretinogram, thought to originate from the spatially sensitive inner retinal layers, was recorded in 16 patients with Alzheimer's disease and 16 age- and gender-matched control subjects under the following two test conditions: (1) optical defocus or inattention, without laser pointer, and (2) optical focus or attention, with laser pointer. By correcting for optical defocus with the laser pointer, control subjects increased their pattern electroretinogram amplitudes by 8% from a mean value of 2.65 microV (standard deviation, 1.12) to 2.87 microV (standard deviation, 0.93), whereas patients with Alzheimer's disease had a 19% increase in pattern electroretinogram amplitude from 2.20 microV (standard deviation, 0.86) to 2.62 microV (standard deviation, 0.64). By controlling for optical defocus, the coefficient of variation (standard deviation/mean) was reduced by 10% (from 42% to 32%) in normal subjects and by 14% (from 39% to 25%) in patients with Alzheimer's disease. A two-way analysis of variance (ANOVA) did not show a significant difference in amplitudes between populations, which indicates that the pattern electroretinogram may not be valuable in establishing an early diagnosis of Alzheimer's disease. In a second study conducted in 20 young, healthy normal subjects, plus lenses were used to defocus the checkerboard stimuli, before recording the pattern electroretinogram. We found that the pattern electroretinogram was extremely sensitive to optical defocusing such that the response amplitude decreased by 13% at 20/25 visual acuity and 19% at 20/30. Reduction of pattern electroretinogram amplitude caused by change in visual acuity is an independent source of artifact.(ABSTRACT TRUNCATED AT 250 WORDS)

Accommodation, Ocular↗
PubMed1988

Detection of a novel catalase in extracts of Mycobacterium avium and Mycobacterium intracellulare.

A novel class of catalase, which differs from the previously described M- and T-catalases of mycobacteria, was detected in strains of Mycobacterium avium and M. intracellulare. Designated A-catalase, this enzyme resisted inactivation at 68 degrees C, was inactivated by 3-amino-1,2,4-triazole (aminotriazole), and exhibited no peroxidase activity. All of these properties distinguished the enzyme from T-catalase. The A-catalase exhibited a Km of 70 mM H2O2, which is between the upper and lower extremes of the ranges reported for T- and M-catalases, respectively. The A-catalase appeared to be more hydrophobic than M-catalase and did not react with antiserum to a representative sample of this class. The banding patterns of T- and M-catalases seen by polyacrylamide gel electrophoresis (PAGE) were essentially unaffected by the incorporation of sodium dodecyl sulfate (SDS) into the PAGE system, whereas the single band of A-catalase seen by PAGE without SDS resolved into as many as five bands in the presence of SDS; these bands were all of slower mobility than the original band. The banding pattern seen with SDS appeared to be related more to counterion charge effects than to molecular size increases that could be attributed to SDS complexed to the protein. It remains to be determined whether the multiple A-catalase bands reflect different proteins or different SDS micellar complexes of a single protein.

Ammonium Sulfate↗
PubMed1976

Behaviour of cell cultures from human amniotic fluid.

The growth pattern of cell cultures originating from 11 amniotic fluid specimens have been observed. From each specimen 2 to 12 primary cultures were set up. In most cases growth started simultaneously in the primary cultures originating from one sample. The primary cultures lasted from 7 to 30 days. A variation was found both between cultures from different pregnancies as well as among cultures obtained from single amniotic fluids. The growth period from setting up the cultures until harvest of the cell lines for biochemical analysis ranged from 20 to 54 days. No connexion was noticed between the time spent in primary culture and the behaviour of the cell line before harvest. The effects of two types of serum (fetal calf serum and pooled human serum) on the behaviour of the cultures were compared. The cells grown in human serum were harvested a few days before those grown in fetal calf serum. The influence of different batches of medium was also examined; no significant effect of the growth pattern was found. The appearance of epithelial-like and fibroblast-like cells in cultures from 6 specimens was observed concurrently. At the time of harvest the cell lines originating from the same amniotic specimen contained the cell types in different proportions.

Amniocentesis↗