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PubMed1979

[Evaluation of mechanical ventilation in meconial aspiration syndrome].

Twenty seven newborn with serious meconial aspiration syndrome are studied. Two groups are stablish weather they require or not mechanical ventilation during evolution. When comparing various perinatal and clinical data, only the Silverman test showed statistically significant differences; pH and gases in blood during the first hours of life did not showed differences. Pneumothorax incidency in both groups was 33%. Twelve newborn required mechanical ventilation. The starting age was 24 hours of life range 3-54 hours. Most frequent indication was hipoxemia and apnea. Use of intermitent positive pressure improved PaCO2 with a light increase in PaO2 though it also increased alveolo-arterial oxygen gradient. Hipoxemia was the most relevant data in evolution of these patients. In seven cases continuous distending pressure was applied, with a light increase in PaO2 only in three patients. No patient suffered pneumothorax during mechanical ventilation. In patients with mechanical ventilation mortality was 25%. The possibility of an addition in certain cases of pulmonary hypertension with right-to-left shunting ductal and atrial is reported.

Age Factors↗

PubMed2004

Evolution of multicellularity in Metazoa: comparative analysis of the subcellular localization of proteins in Saccharomyces, Drosophila and Caenorhabditis.

A comparison of the subcellular assignments of proteins between the unicellular Saccharomyces cerevisiae and the multicellular Drosophila melanogaster and Caenorhabditis elegans was performed using a computational tool for the prediction of subcellular localization. Nine subcellular compartments were studied: (1) extracellular domain, (2) cell membrane, (3) cytoplasm, (4) endoplasmic reticulum, (5) Golgi apparatus, (6) lysosome, (7) peroxisome, (8) mitochondria, and (9) nucleus. The transition to multicellularity was found to be characterized by an increase in the total number of proteins encoded by the genome. Interestingly, this increase is distributed unevenly among the subcellular compartments. That is, a disproportionate increase in the number of proteins in the extracellular domain, the cell membrane, and the cytoplasm is observed in multicellular organisms, while no such increase is seen in other subcellular compartments. A possible explanation involves signal transduction. In terms of protein numbers, signal transduction pathways may be roughly described as a pyramid with an expansive base in the extracellular domain (the numerous extracellular signal proteins), progressively narrowing at the cell membrane and cytoplasmic levels, and ending in a narrow tip consisting of only a handful of transcription modulators in the nucleus. Our observations suggest that extracellular signaling interactions among metazoan cells account for the uneven increase in the numbers of proteins among subcellular compartments during the transition to multicellularity.

Animals↗

PubMed1982

Comparative morphological features of the caecilian inner ear with comments on the evolution of amphibian auditory structures.

Comparative fine structural studies of amphibian auditory structures in urodeles have been extended to include examination of the papilliform end-organs (amphibian, neglecta and basilar) that variably occur in species selected from three families of caecilians (Gymnophiona). The species investigated were Ichthyophis kohtaoensis (Ichthyophiidae), Dermophis mexicanus (Caeciliidae) and Typhlonectes natans (Typhlonectidae). Ichthyophis is the only form to display all three papillae; both Dermophis and Typhlonectes lack a basilar papilla but all three species show both neglecta and amphibiorum. In these forms, the amphibian papilla contained the most sensory cells with ciliary bundles organized into two proximal and distal groups polarized toward a mid-line papillar axis. The papilla neglecta contained slightly fewer sensory cells and ciliary bundles oriented predominantly posteriorly. In Ichthyophis, the basilar papilla contained the lowest sensory cell counts of any papilla. Here, basilar sensory cilia were unidirectionally polarized away from the saccule. All papillae were overlain by an essentially similar, extracellular tectorial body. When compared to auditory end-organs in the urodeles and anurans, similar conditions in caecilians are suggestive of a common ancestry for the basilar and amphibian papillae; features of the amphibiorum indicate further that it may represent part of a "displaced" papilla neglecta.

Amphibians↗

PubMed2005

Methods for studying the evolution of plant reproductive structures: comparative gene expression techniques.

A major component of evolutionary developmental (evo-devo) genetics is the analysis of gene expression patterns in nonmodel species. This comparative approach can take many forms, including reverse-transcriptase polymerase chain reaction, Northern blot hybridization, and in situ hybridization. The choice of technique depends on several issues such as the availability of fresh tissue, as well as the expected expression level and pattern of the candidate gene in question. Although the protocols for these procedures are fairly standard, optimization is often required because of the specific characteristics of the species under analysis. This chapter describes several methods commonly used to determine gene expression patterns in angiosperms, particularly in floral tissues. Suggestions for adapting basic protocols for diverse taxa and troubleshooting are also extensively discussed.

Biological Evolution↗

PubMed2005

Cognitive function in bulbar- and spinal-onset amyotrophic lateral sclerosis. A longitudinal study in 52 patients.

We performed a longitudinal study of frontal and temporal lobe functions in patients with amyotrophic lateral sclerosis (ALS) and compared the evolution of cognitive performance with that of motor deficits in patients with spinal and bulbar-onset of the disease. Fifty two patients suffering from sporadic ALS according to the El Escorial criteria were examined; 37 patients had a spinal, 15 a bulbar onset of the disease. The data profile included examinations at entry (E1), every four months at follow-up (E2, E3, E4) and after 18 months (E5), if possible. Neuropsychological testing covered the domains of executive functions, memory and attentional control. ALS patients showed executive dysfunctions that were most prominently represented by deficits of non-verbal and verbal fluency and concept formation. Memory-related deficits were also present but less expressed. The same held true for phasic and tonic alertness and divided attention. In contrast to motor functions declining concomitantly with disease progression, cognitive deficits appeared in early disease, were essentially present at initial testing and did not substantially decline on follow-up. A subgroup analysis revealed that bulbar-onset ALS patients performed consistently poorer in many cognitive tests than spinal-onset ones with special reference to verbal and non-verbal fluency and interference control. This subgroup difference persisted or even increased throughout follow-up. We conclude that there is a fronto-temporal pattern of cognitive dysfunction in ALS expressing itself early in the course of the disease and mainly with bulbar forms. The cognitive deficits do not progress in synchrony with motor decline, but distinctly more slowly. We suggest that cognitive dysfunctions reflect functional and possibly morphological deficits outside the primary motor system that is specific for the nature and evolution of the disease and might also give clues to etiopathogenesis.

Aged↗

PubMed1998

A stochastic model for the rapid emergence of specific vertebrate immunity incorporating horizontal transfer of systems enabling duplication and combinational diversification.

Recent molecular data indicate that the antigen-specific combinatorial immune response is restricted to jawed vertebrates where it is found in representatives of all class from cartilagenous fishes to mammals. Here, we analyse the relatively rapid emergence of the combinatorial system terms of three stochastic process, with the system reaching essentially full capacity in immunoglobulin recognition elements and diversification and recombination of gene segments in an evolutionary span of time of less than 20 million years. The mechanisms for inducibility were coopted from ancient and widely spread processes in phylogeny for regulation of cell division. The proposed process of formation entailed the evolution of unknown ancestral genes into those specifying bona fide immunoglobulin domains, and the generation of multiple copies of these via a series of events facilitated by horizontal transfer of site-specific recombinases and recombination signal sequences most probably from microbial and fungal sources. The second process is one of rapid "decay" (evolution) which occurred in about 10 million year under stringent selective conditions to generate proper conserved canonical sequences. The third process is that of the long term evolution of these characteristic immunoglobulin domains over the 450 million years since their emergence. As a first approximation the rates of these three processes were computed using first order differential equations. The rate of formation has a magnitude of 10-7 substitutions per site per year, and that of rapid modifications is 10-8 substitutions per site per year. The long term rate of immunoglobulin evolution is comparable to that of other moderately conserved proteins, (1-3) x 10-9 substitutions per site per year). This model is testable by searching for "footprints" of microbial and fungal DNA processing enzymes and recombination mechanisms. The hypothesis raises the general concept that horizontal transfer of genes facilitating rearrangement and duplication can catalyse major steps of macroevolution.

Animals↗

PubMed2004

Comparative analysis of gene expression for convergent evolution of camera eye between octopus and human.

Although the camera eye of the octopus is very similar to that of humans, phylogenetic and embryological analyses have suggested that their camera eyes have been acquired independently. It has been known as a typical example of convergent evolution. To study the molecular basis of convergent evolution of camera eyes, we conducted a comparative analysis of gene expression in octopus and human camera eyes. We sequenced 16,432 ESTs of the octopus eye, leading to 1052 nonredundant genes that have matches in the protein database. Comparing these 1052 genes with 13,303 already-known ESTs of the human eye, 729 (69.3%) genes were commonly expressed between the human and octopus eyes. On the contrary, when we compared octopus eye ESTs with human connective tissue ESTs, the expression similarity was quite low. To trace the evolutionary changes that are potentially responsible for camera eye formation, we also compared octopus-eye ESTs with the completed genome sequences of other organisms. We found that 1019 out of the 1052 genes had already existed at the common ancestor of bilateria, and 875 genes were conserved between humans and octopuses. It suggests that a larger number of conserved genes and their similar gene expression may be responsible for the convergent evolution of the camera eye.

Animals↗

PubMed2004

The sex-ratio trait and its evolution in Drosophila simulans: a comparative approach.

Sex-ratio X chromosomes, which prevent the production of Y-bearing sperm, have been identified in a dozen Drosophila species covering a wide phylogenetic range. It has not yet been established whether the same ancestral genetic system underlies this type of meiotic drive across the genus, but the biological characteristics and the evolutionary history of species undoubtedly determine the fate of X-linked drivers. The intragenomic conflict they trigger contributes to geographical variation in D. simulans, which shows a sharp contrast between ancestral-stock derived and recently introduced populations. In the former, sex-ratio X chromosomes are widespread and sometimes reach a high frequency, but they are inactivated by strong Y-linked and autosomal drive suppressors. In recently-introduced populations, sex-ratio X chromosomes are generally rare and suppressors are moderate or absent. We discuss how this pattern could be related to the recent geographical expansion of D. simulans, and consider possible reasons why sex-ratio drive apparently does not occur in D. melanogaster.

Animals↗

PubMed1995

Variable cell positions and cell contacts underlie morphological evolution of the rays in the male tails of nematodes related to Caenorhabditis elegans.

As a first step toward understanding their mechanism of morphological evolution, we compare the morphology and development of the male genitalia in 10 species of Rhabditidae, the family of nematodes that includes Caenorhabditis elegans. We describe a number of variable morphological characteristics and focus in particular on the differing arrangements of the caudal papillae or rays within the acellular fan. We analyze the development of the ray cells within the epidermis of the last larval stage and identify changes in cell positions and cell contacts that underlie evolutionary changes in the arrangement of the rays. Epidermal cell positions were determined by means of indirect immunofluorescence staining with a monoclonal antibody directed towards adherens junctions. Similarities between the species in the cellular arrangements during the earliest developmental stages allow us to propose homologies between the rays in different species. Evolutionary changes in the positions and order of homologous rays are correlated with shifts in cell positions during development. The results suggest that genes for cell recognition or adhesion proteins, or pattern formation genes that regulate cell recognition or adhesion proteins, may be important foci of evolutionary change affecting morphology.

Animals↗

PubMed1999

Isolation and sequence of a cDNA coding for the heavy chain constant region of IgG from the Australian brushtail possum, Trichosurus vulpecula.

A brushtail possum (Trichosurus vulpecula) mesenteric lymph node cDNA library was screened with a South American short-tailed opossum (Monodlelphis domestica) immunoglobulin gamma heavy chain constant region (Cgamma) probe, resulting in the isolation of a 1518 nucleotide cDNA clone. The sequence corresponds to exons 1-3 of Cgamma. The Australian marsupial (T. vulpeculla) sequence is 70% identical at the amino acid level with the American marsupial (M. domestica) sequence, but less similar to the eutherian mammals (45-50%). These data provide the opportunity to compare the evolution of IgG between orders of marsupials separated by at least 75 million years and confirm the appearance of IgG prior to the metatherian/eutherian divergence.

Amino Acid Sequence↗

PubMed2001

A comparative analysis of the immunological evolution of antibody 28B4.

In an effort to gain greater insight into the evolution of the redox active, catalytic antibody 28B4, the germline genes used by the mouse to generate this antibody were cloned and expressed, and the X-ray crystal structures of the unliganded and hapten-bound germline Fab of antibody 28B4 were determined. Comparison with the previously determined structures of the unliganded and hapten-bound affinity-matured Fab [Hsieh-Wilson, L. C., Schultz, P. G., and Stevens, R. C. (1996) Proc. Natl. Acad. Sci. U.S.A. 93, 5363] shows that the germline antibody binds the p-nitrophenyl ring of hapten 3 in an orientation significantly different from that seen in the affinity-matured antibody, whereas the phosphonate moiety is bound in a similar mode by both antibodies. The affinity-matured antibody 28B4 has more electrostatic and hydrophobic interactions with hapten 3 than the germline antibody and binds the hapten in a lock-and-key fashion. In contrast, significant conformational changes occur in the loops of CDR H3 and CDR L1 upon hapten binding to the germline antibody, consistent with the notion of structural plasticity in the germline antibody-combining site [Wedemayer, G. J., Patten, P. A., Wang, L. H., Schultz, P. G., and Stevens, R. C. (1997) Science 276, 1665]. The structural differences are reflected in the differential binding affinities of the germline Fab (K(d) = 25 microM) and 28B4 Fab (K(d) = 37 nM) to hapten 3. Nine replacement mutations were found to accumulate in the affinity-matured antibody 28B4 compared to its germline precursor. The effects of each mutation on the binding affinity of the antibody to hapten 3 were characterized in detail in the contexts of both the germline and the affinity-matured antibodies. One of the mutations, Asp95(H)Trp, leads to a change in the orientation of the bound hapten, and its presence is a prerequisite for other somatic mutations to enhance the binding affinity of the germline antibody for hapten 3. Thus, the germline antibody of 28B4 acquired functionally important mutations in a stepwise manner, which fits into a multicycle mutation, affinity selection, and clonal expansion model for germline antibody evolution. Two other antibodies, 20-1 and NZA6, with very different antigen specificities were found to be highly homologous to the germline antibody of 28B4, consistent with the notion that certain germline variable-region gene combinations can give rise to polyspecific hapten binding sites [Romesberg, F. E., Spiller, B., Schultz, P. G., and Stevens, R. C. (1998) Science 279, 1929]. The ultimate specificity of the polyspecific germline antibody appears to be defined by CDR H3 variability and subsequent somatic mutation. Insights into the evolution of antibody-combining sites provided by this and other structural studies are discussed.

Amino Acid Sequence↗

PubMed1989

Mode of Action of the Massively Accumulated beta-Carotene of Dunaliella bardawil in Protecting the Alga against Damage by Excess Irradiation.

When grown under defined conditions Dunaliella bardawil accumulates a high concentration of beta-carotene, which is composed primarily of two isomers, all-trans and 9-cis beta-carotene. The high beta-carotene alga is substantially resistant to photoinhibition of photosynthetic oxygen evolution when compared with low beta-carotene D. bardawil or with Dunaliella salina which is incapable of accumulating beta-carotene. Protection against photoinhibition in the high beta-carotene D. bardawil is very strong when blue light is used as the photoinhibitory agent, intermediate with white light, and nonexistent with red light. These observations suggest that the massively accumulated beta-carotene in D. bardawil protects the alga against damage by high irradiation by screening through absorption of the blue region of the spectrum. Irradiation of D. bardawil by high intensity blue light results in the following temporal sequence of events: photoinhibition of oxygen evolution, photodestruction of 9-cis beta-carotene, photodestruction of all-trans beta-carotene, photodestruction of chlorophyll and cell death.

Journal Article↗

PubMed2003

Nodular leprosy of childhood and tuberculoid leprosy: a comparative, morphologic, immunopathologic and quantitative study of skin tissue reaction.

Nodular leprosy of childhood (NL) is a benign clinical variant of tuberculoid leprosy that affects breast-feeding infants and children that remained in a highly infected environment. The lesions resolve with complete healing and NL has been considered a manifestation of allergy and congenital immunity to Mycobacteria leprae. We studied the tissue reaction, Mycobacterial antigen frequency, and the lymphocyte subsets (CD45RO+, CD4+, CD8+, B, NK), dendritic cells (epidermal CD1a+ cells and S100+ dermal dendrocytes), and macrophages in skin lesions of a clinically well characterized NL group (N = 11). Results were compared to children (N = 23) and adults (N = 24) with classical tuberculoid leprosy. NL lesion histopathology was characterized by dense granulomatous inflammatory reaction, with a greater number of confluent tubercles when compared to the other groups. Neural compromise was seen in all biopsies. The frequency of Mycobacterium antigen was similar in all groups. The population of CD45RO+, CD4+ and CD8+ T lymphocytes, natural killer cells, B lymphocytes, CD1a+ epidermal cells, and macrophages of NL lesions did not differ from the other groups. The number of S100+ dermal dendritic cells of the NL group was smaller than that of the adult group, although it did not differ from the other group of children. Except for the confluent tubercules, our data could not disclose any other difference in the tissue reaction of NL, in spite of its peculiar clinical features and evolution when compared with the classical tuberculoid leprosy. The localization of NL lesions may be the result of the intimate skin contact with lepromatous parents or relatives, in areas such as cheeks, arms, buttocks, and limbs, and the innoculation of M. leprae into skin may strongly stimulate cell mediated immunity (CMI) against the bacilli. These circumstances might explain the good CMI response leading to high resistance, stability, and auto-resolution of nodular leprosy of childhood.

Adolescent↗

PubMed1987

Molecular studies of marsupial X chromosomes reveal limited sequence homology of mammalian X-linked genes.

To explore the extent to which the X chromosome has been conserved during mammalian evolution, we compared six loci that are X-linked in the human genome with the corresponding genes of the North American marsupial, the Virginia opossum (Didelphis virginiana). Our analysis shows that in the opossum genome there are sequences highly homologous to those of human cDNAs for housekeeping genes, glucose-6-phosphoribosyltransferase (HPRT), phosphoglycerate kinase A (PGK1), and alpha-galactosidase A (GLA). However, ornithine transcarbamylase and blood clotting Factor IX--tissue-specific genes that are X-linked in eutherians mammals--have no highly conserved homologs in the marsupial genome. By cloning opossum G6PD and HPRT, we found that these genes are X-linked in the opossum and that homologous sequences are limited to coding regions. As all genomic fragments hybridizing with the human GLA probe show dosage effects, it is likely that the opossum counterpart is X-linked. Finally, the pattern of hybridization suggests that the autosomal pseudogenes of HPRT and PGK1 in the opossum have remained highly homologous to the human X-linked genes.

Animals↗

PubMed1997

Occult spinal dysraphism: neurogenic voiding dysfunction and long-term urologic follow-up

From 1976 to 1994, we followed 55 children with occult spinal dysraphism (OSD). The average age at diagnosis was 4.5 years (range: 24 days - 21 years). In 13 cases the OSD was associated with anorectal anomalies. Urologic symptoms were present at diagnosis in 24 children (43%), but urinary incontinence affected all patients in the evolution of the OSD. At diagnosis, all children underwent complete neurourologic and urodynamic evaluation. Nine required early neurosurgical correction, before 3 years of age. During follow-up, intermittent clean catheterization was started in all patients. Vesicoureteral reflux was present or developed in 17 patients: 15 underwent endoscopic procedures and 2 required bladder augmentation because of upper-tract and renal-function deterioration. Endoscopic treatment for urinary incontinence was performed in 3 children. At long-term follow-up (6 to 18 years), socially acceptable continence was achieved in 78% of the children; renal failure occurred in 8. The long-term results were analyzed in order to compare the evolution of urinary continence and renal function in children with OSD with or without neurosurgery.

Journal Article↗

PubMed1997

Occult spinal dysraphism: neurogenic voiding dysfunction and long-term urologic follow-up.

Adolescent↗

PubMed1996

Coronary stenosis progression differs in patients with stable angina pectoris with and without a previous history of unstable angina.

OBJECTIVES: To compare the evolution of stenoses responsible for acute coronary events with those not associated with acute coronary syndromes. METHODS AND RESULTS: We prospectively studied angiographic stenosis progression in 190 stable angina patients, with single vessel disease, who were awaiting non-urgent coronary angioplasty. Sixty four patients had a previous history of unstable angina (Group 1) and 126 patients had no history of unstable angina (Group 2). Culprit stenoses were classified as "complex' or "smooth'. At restudy, 8 +/- 4 months after the first angiogram, 12 of 63 culprit stenoses in Group 1 had progressed and seven of 125 in Group 2 (19% vs 6%, P = 0.0044). Thirteen of 68 complex culprit stenoses had progressed, compared with only 6 of 120 smooth culprit stenoses (19% vs 5%, P = 0.003). Coronary events occurred in 12 Group 1 patients and nine Group 2 patients (P = 0.02). CONCLUSIONS: In patients with stable angina, stenoses associated with previous episodes of unstable angina are more likely to progress than stenoses not associated with previous unstable angina. Unstable coronary atherosclerotic plaques, even those that have been clinically stable for more than 3 months, may retain the potential for rapid progression to total occlusion.

Adult↗

PubMed2003

[Triple-blind clinical trial with placebo control to evaluate the efficacy of a heparin of low molecular weight (bemiparin) for treating slow-responding ulcers in diabetic foot in primary care].

OBJECTIVES: To establish the degree of efficacy of bemiparin treatment over 3 months in the improvement of slow-responding ulcers in diabetic foot. Also, to evaluate the safety of bemiparin and quality of life and to compare the evolution of retinopathy and nephropathy against placebo. DESIGN: Stage III clinical trial to evaluate efficacy and safety in a new indication of a medicine already on the market, parallel in two branches, randomised, triple-blind, and controlled with placebo. SETTING: Health care centres in Mallorca, Spain. PARTICIPANTS: 42 patients per branch, over 18, with type-1 or 2 DM of over 3 years evolution, and one or more first or second-degree ulcers on the Wagner scale, distal to the knee, that did not heal in three months of health care. Randomised allocation in blocks of four.Interventions. The experimental drug was bemiparin (heparin of low molecular weight), injected subcutaneously at 3500 IU/day for the first 10 days and 2500 IU/day up to 90 days. As control, physiological serum was injected sub-cutaneously in a similar volume for masking. MAIN MEASUREMENTS: An "effect"was defined as a reduction of at least 50% in its surface area and/or a favourable evolution in status to a degree between the control at the start of treatment and at three months. Other measurements included proteinuria, retinography and quality of life (SF-36). Analysis of efficacy through principle of intention to treat.

Adult↗