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At least 667 records · Page 37Linked to original sources

PubMed2003

Opsoclonus: an early sign of neonatal herpes encephalitis.

Preferential involvement of certain central nervous systems areas by specific viruses provides a valuable guide to the selection of antiviral agents. We report a neonate that developed opsoclonus 7 days prior to the diagnosis of herpes simplex type 2 cerebellitis. The course of the opsoclonus paralleled the clinical course and radiologic evolution of the infection. The purpose of this report is to describe opsoclonus as a possible early sign of herpes simplex type 2 central nervous system infection.

Cerebellum↗

PubMed1992

Women healers of the middle ages: selected aspects of their history.

The stellar role of women as healers during the Middle Ages has received some attention from medical historians but remains little known or appreciated. In the three centuries preceding the Renaissance, this role was heightened by two roughly parallel developments. The first was the evolution of European universities and their professional schools that, for the most part, systematically excluded women as students, thereby creating a legal male monopoly of the practice of medicine. Ineligible as healers, women waged a lengthy battle to maintain their right to care for the sick and injured. The 1322 case of Jacqueline Felicie, one of many healers charged with illegally practicing medicine, raises serious questions about the motives of male physicians in discrediting these women as incompetent and dangerous. The second development was the campaign--promoted by the church and supported by both clerical and civil authorities--to brand women healers as witches. Perhaps the church perceived these women, with their special, often esoteric, healing skills, as a threat to its supremacy in the lives of its parishioners. The result was the brutal persecution of unknown numbers of mostly peasant women.

Clinical Medicine↗

PubMedDate not supplied

Delayed MR imaging changes in acute disseminated encephalomyelitis.

BACKGROUND AND PURPOSE: White matter lesions on MR images obtained from patients with acute disseminated encephalomyelitis (ADEM) have been reported to appear shortly after symptom onset, and their resolution has been claimed to parallel recovery. To elucidate the temporal evolution of these lesions and to associate the changes on MR images to the patients' clinical condition, we performed serial MR imaging on patients with ADEM. METHODS: Several consecutive T2-weighted and fluid-attenuated inversion recovery scans were obtained from four previously healthy adult patients with ADEM within the first days after the onset of symptoms and again during the recovery period. MR imaging was done first on a weekly to biweekly basis and later at 1- to 2-month intervals for up to 8 months. RESULTS: MR scans of three of these patients did not show any specific abnormalities until several weeks after the onset of the disease. As the lesions later appeared, their number increased during the recovery period. CONCLUSION: MR imaging performed during the first days after the onset of the disease may not reveal any pathologic findings. The appearance of the ADEM-associated MR imaging changes may be associated with recovery rather than decline. It remains to be studied whether the new MR imaging techniques reveal the lesions associated with ADEM faster than the conventional T2-weighted imaging.

Adult↗

PubMed1980

Aromatic amines (serotonin and histamine) and magnesium deficiency in the rat.

Rats were made deficient by giving a 4 mg Mg/100 g diet. The control diet content was 40 mg Mg/100 g. Serotonin injected to magnesium deficient and control rats was metabolized at the same rate in both groups and the urinary derivatives were similar. Serotonin catabolism can occur in liver as shown by isolated hepatocyte technique. Hyperemia of the ears and dermatosis appeared in magnesium deficient rats, while histaminemia rised. This allergy-like crisis was delayed and milder, when the food intake was reduced. The evolution of histaminemia was studied in parallel with the different white blood cells, during three periods of magnesium deficiency. An important rise of total white blood cells, specially poly morphonuclear and eosinophil cells was observed. The peak for eosinophils occured before the histaminemia and basophils peaks. Basophils cells found only in magnesium deficient group were partly degranualted.

Animals↗

PubMed1993

IgA antibodies to a protective antigen in human Schistosomiasis mansoni.

The specific IgA antibody responses to the protective recombinant Schistosoma mansoni 28-kDa glutathione-S-transferase (Sm28GST) Ag and to derived synthetic peptides have been evaluated before and 6 mo after chemotherapy in S. mansoni-infected patients from Kenya. These studies revealed a parallelism between the age-dependent evolution of IgA antibody levels to Sm28GST and to one synthetic peptide (115-131) and the acquisition of resistance to reinfection. Functional analysis revealed that IgA antibodies to Sm28GST displayed a potent neutralizing effect on the enzymatic properties of the molecule, and also markedly impaired schistosome fecundity, by limiting both the egg laying of mature worms and the hatching capacity of schistosome eggs into viable miracidia. These results suggest that, in addition to IgE, IgA antibodies might participate in the protective immune response against schistosomiasis.

Adolescent↗

PubMed1995

Calcium modulates the photoassembly of photosystem II (Mn)4-clusters by preventing ligation of nonfunctional high-valency states of manganese.

The requirement for Ca2+ in the Mn(2+)-dependent photoactivation of oxygen evolution was re-evaluated using 17 kDa/24 kDa-less photosystem II (PSII) membranes depleted of (Mn)4-clusters by NH2OH extraction. At optimum conditions (1 mM Mn2+/10 microM 2,6-dichlorphenolindophenol (DCIP)/20 mM Ca2+), the light-induced increase of oxygen-evolution activity, the increase of membrane-bound Mn, and the B-band thermoluminescence emission intensity occurred in parallel. The extent of recovery of the oxygen-evolution activity was equivalent to 88% and 66% of the activity shown by parent NaCl-extracted PSII membranes and by PSII membranes, respectively. Neither photodamage of primary electron transport nor photoligation of nonfunctional Mn > or = 3+ occurred. Analyses of the Ca2+ concentration dependence for the maximum recovery of oxygen evolution activity gave evidence for Ca(2+)-binding site(s) having Km values of approximately 38 and approximately 1300 microM. Illumination of membranes in the strict absence of Ca2+ resulted in large increases (up to 18 Mn/200 chlorophyll) of EDTA nonextractable, EPR silent, nonfunctional membrane-bound Mn > or = 3+ and small increases of oxygen-evolution capability, dependent on pH and concentrations of Mn2+ and DCIP. No photodamage of primary electron transport and only approximately 17% decrease of AT-band thermoluminescence occurred during the photoligation of the Mn > or = 3%. In the strict absence of Ca2+, significant recovery of oxygen-evolution activity was obtained under a limited set of conditions permitting photoligation of a limited abundance of the nonfunctional Mn > or = 3+. Small (NH2-OH, H2O2) as well as bulky external reductants readily reduced and dissociated the Mn > or = 3+ from the membranes. Reillumination of these membranes under optimal conditions for photoactivation (plus Ca2+) gave a high yield of (Mn)4-clusters and oxygen-evolution capability. Similarly, simple addition of Ca2+ to membranes containing nonfunctional Mn > or = 3+ followed by reillumination resulted in the conversion of Mn > or = 3+ to (Mn)4-clusters. It is argued that Ca2+ promotes the conformational change involved in the conversion of the Mn2+ mononuclear intermediate to the Mn(3+)-Mn2+ binuclear intermediate in the photoactivation mechanism, thereby permitting photoassembly of (Mn)4-clusters and preventing photo-inactivation by Mn > or = 3+ ions.

2,6-Dichloroindophenol↗

PubMed2006

[Art and nose].

The author describes over a period of five thousands years the evolution of the esthetical criteria of the artists, painters and sculptors who have represented the nasal pyramid. Starting from prehistorical times to great civilisations: Roman and Greek, then to the age of the Renaissance, and to end in the modern times with impressionism, cubism and surrealism. As a conclusion, he draws a parallel between rhinoplasty and the different technical evolutions, according to the esthetic patterns of the rhinoplasticians and the different human qualities they should have to master this technique.

Art↗

PubMed1996

[Cutaneous manifestations of acromegaly: 4 cases].

INTRODUCTION: Some skin changes in acromegaly belong to the classical dysmorphic syndrome. Furthermore, other minor skin changes can be associated. OBSERVATIONS: We report 3 patients consulting in the department of Dermatology for various skin changes that have lead to the diagnosis of acromegaly. However these patients have also typical dysmorphic syndrome that they have failed to recognize. The fourth patient associated a cutaneous mastocytosis and acromegaly, as reported only once in literature. The evolution of the minor skin changes was parallel with the endocrinopathy. Moreover in one case, they have preceded the recurrence of the acromegaly. COMMENTS: Our observations demonstrate the importance of the minor skin changes that lead the patient to consult more than the dysmorphic syndrome. Moreover these changes that depend of growth hormone and other associated growth factors can be evolutive signs for endocrinopathy.

Acromegaly↗

PubMed1982

[C-reactive protein and orosomucoid as parameters of developmental monitoring and therapeutic effectiveness in neonatal sepsis].

Authors develop a comparative study of two acute phase reactants behaviour, in the follow up on 27 neonates with confirmed sepsis of favourable evolution and in 15 cases with fatal evolution. Results show that sera levels C-reactive-protein follow a parallel course with clinical significance in patients reaching normal concentrations soon after favourable evolution and persisting in high level or even increasing previous ones, in cases of lethal evolution. Orosomucoid did show the same clinical-biological correlation maintaining generally in high levels independent of normalization of symptoms and C-reactive protein. They propose serial determination of C-reactive-protein and an efficient control of treatment in neonatal sepsis.

Anti-Bacterial Agents↗

PubMed2005

A biogeographic pattern in sparrow bill morphology: parallel adaptation to tidal marshes.

The study of ecological convergence, the evolution of similar traits on multiple occasions in response to similar conditions, is a powerful method for developing and testing adaptive hypotheses. However, despite the great attention paid to geographic variation and the foraging ecology of birds, surprisingly few cases of convergent or parallel feeding adaptations have been adequately documented. In this study, we document a biogeographic pattern of parallel bill morphology across 10 sparrow taxa endemic to tidal marshes. All North American tidal marsh sparrows display parallel differentiation from close relatives in other habitats, suggesting that selection on bill morphology is strong. Relative to their body mass, tidal marsh sparrows have longer, thinner bills than their non-tidal marsh counterparts, which is likely an adaptation for consuming more invertebrates and fewer seeds, as well as for probing in sediment crevices to capture prey. Published data on tidal marsh food resources and diet of the relevant taxa support this hypothesis. This morphological differentiation is most pronounced between sister taxa with the greatest estimated divergence times, but is found even in taxa that show little or no structure in molecular genetic markers. We, therefore, speculate that tidal marsh ecosystems are likely settings for ecological speciation.

Adaptation, Biological↗

PubMed2006

[Yawning: from birth to senescence].

Yawning is one of the most under-appreciated behaviors. It is a stereotyped and often repetitive motor act, characterized by gaping of the mouth accompanied by a long inspiration, a brief acme followed by a short expiration. The vigor of the act may increase arousal. Although socially offensive to many, yawns often bring pleasure to the yawner. While influenced by several neurotransmitters, yawning is strongly affected by dopamine. Dopamine activates oxytocin production in the paraventricular nucleus of the hypothalamus, oxytocin may then activate cholinergic neurotransmission in the hippocampus and the reticular formation of the brainstem. Acethylcholine induces yawning via the muscarinic receptors of effectors. Other neurotransmitters can modulate its occurence like serotonin, neuropeptides, hypocretin and sexual hormones. The decrease of yawning in the elderly suggests an associated decrease of dopaminergic activity. Yawning and stretching have related phylogenetic old origins. Ethologists agree that most vertebrates yawn. Yawning is morphologically similar in reptiles, birds, mammals and fishes. They may be ancestral vestiges surviving throughout evolution with little variation. In the human embryo, yawning occurs as early as 12 weeks after conception and remains relatively unchanged throughout life. Across the life span, night sleep undergoes several age-related modifications. Theses changes concern sleep duration and the amount of REM and NREM sleep. We can describe, for the duration of REM sleep, a curvilinear trend with a steep descending slope in the last time of fetus life and the first year of life, a plateau level across childhood and adulthood, slowly lowering until age. A parallel curve demonstrates the similarity of the evolution of yawn's frequency and the amount of REM sleep. Thus, from ontogeny, phylogeny and this modelling approach emerges a pivotal link between yawning and REM sleep. Yawning is modified in some pathologies associated with aging.

Adolescent↗

PubMed2004

Integrating the genotype and phenotype in hominid paleontology.

Competing interpretations of human origins and evolution have recently proliferated despite the accelerated pace of fossil discovery. These controversies parallel those involving other vertebrate families and result from the difficulty of studying evolution among closely related species. Recent advances in developmental and quantitative genetics show that some conventions routinely used by hominid and other mammalian paleontologists are unwarranted. These same advances provide ways to integrate knowledge of the genotype into the study of the phenotype. The result is an approach that promises to yield a fuller understanding of evolution below the family level.

Animals↗

PubMed1984

Experimental determination of the respiration associated with soybean/rhizobium nitrogenase function, nodule maintenance, and total nodule nitrogen fixation.

The total metabolic cost of soybean (Glycine max L. Mer Clark) nodule nitrogen fixation was empirically separated into respiration associated with electron flow through nitrogenase and respiration associated with maintenance of nodule function.Rates of CO(2) evolution and H(2) evolution from intact, nodulated root systems under Ar:O(2) atmospheres decreased in parallel when plants were maintained in an extended dark period. While H(2) evolution approached zero after 36 hours of darkness at 22 degrees C, CO(2) evolution rate remained at 38 degrees of the rate measured in light. Of the remaining CO(2) evolution, 62% was estimated to originate from the nodules and represents a measure of nodule maintenance respiration. The nodule maintenance requirement was temperature dependent and was estimated at 79 and 137 micromoles CO(2) (per gram dry weight nodule) per hour at 22 degrees C and 30 degrees C, respectively.The cost of N(2) fixation in terms of CO(2) evolved per electron pair utilized by nitrogenase was estimated from the slope of H(2) evolution rate versus CO(2) evolution rate. The cost was 2 moles CO(2) evolved per mole H(2) evolved and was independent of temperature.In this symbiosis, nodule maintenance consumed 22% of total respiratory energy while the functioning of nitrogenase consumed a further 52%. The remaining respiratory energy was calculated to be associated with ammonia assimilation, transport of reduced N, and H(2) evolution.

Journal Article↗

PubMed2006

Pattern of gene duplication in the Cotesia congregata Bracovirus.

Polydnaviruses (PDVs) are a family of double-stranded DNA viruses genetically linked to their wasp hosts. These viruses utilize the transcriptional machinery of the wasp cells to manufacture viral particles which contain circular segments of DNA. The female wasp, hosting the polydnavirus, lays its eggs along with the viral particles inside a caterpillar. Because no replication of the virus occurs while inside the caterpillar, fixed genetic changes occur solely inside the female wasp, as an integrated portion of its genome. Therefore, evolution of the polydnavirus is expected to parallel that of the wasp. Phylogenetic analysis of the polydnavirus genome showed a pattern of gene duplication consistent with the "birth-and-death" process frequently observed in eukaryotic genomes. Phylogenies provided no unequivocal evidence of horizontal gene transfer between the wasp host and the polydnavirus, but in some cases there were suggestions of such gene transfer.

Animals↗

PubMed2005

Atrazine and alachlor inputs to surface and ground waters in irrigated corn cultivation areas of Castilla-Leon region, Spain.

The inputs of atrazine and alachlor herbicides to surface and ground waters from irrigated areas dedicated to corn cultivation in the Castilla-León (C-L) region (Spain) as related to the application of both herbicides were studied. Enzyme-linked immunosorbent assays (ELISA) were used for monitoring the atrazine and alachlor concentrations in 98 water samples taken from these areas. Seventy-nine of the samples were of ground waters and 19 were of surface waters. The concentration ranges of the herbicides detected in the study period (October 1997-October 1998) were 0.04-25.3 microg L(-1) in the surface waters and 0.04-3.45 microg L(-1) in the ground waters for atrazine, and 0.06-31.9 microg L(-1) in the surface waters and 0.05-4.85 microg L(-1) in the ground waters in the case of alachlor. The highly significant correlation observed between the concentrations of both herbicides in the surface waters (r = 0.89, p < 0.001) pointed to a parallel transport of atrazine and alachlor to these waters. A study was made of the temporal evolution of the concentrations of both herbicides, and it was found a maximum recharge of atrazine in the ground waters for April 1998 and of alachlor in October 1997 and October 1998. The temporal evolution of the concentrations of both herbicides in surface waters was parallel. The highly significant correlations observed between atrazine concentrations determined by ELISA and by HPLC (r = 0.92, p < 0.001) and between alachlor concentrations also determined by both methods (r = 0.96, p < 0.001) confirmed the usefulness of ELISA for monitoring both herbicides in an elevated number of samples. Using HPLC, the presence in some waters of the alachlor ethanesulfonate (ESA) metabolite was found at a concentration range of 0.52-4.01 microg L(-1). However the interference of ESA in the determination of alachlor by ELISA was negligible. The inputs of atrazine and alachlor to waters found in this study, especially the inputs to ground waters, could pose a risk for human health considering that some waters, though sporadically, are even used for human consumption.

Acetamides↗

PubMed1983

Light-Stimulated Changes in the Acidity of Suspensions of Oat Protoplasts: Dependence upon Photosynthesis.

Light induced an alkalinization and stimulated a subsequent acidification of the medium surrounding oat (Avena sativa L. cv Garry) leaf protoplasts. Blue light was less effective than would be predicted from photosynthetic action spectra. Nonetheless, 3-(3,4-dichlorophenyl)-1,1-dimethylurea prevented alkalinization and reduced acidification to the dark rate for protoplast suspensions exposed to all light regimes tested.Alkalinization increased in parallel with initial rates of O(2) evolution as the quantum flux density of white light was raised to 75 microeinsteins per square meter per second. Alkalinization was accompanied by a decrease in the CO(2) content of the medium; therefore, it was attributed to photosynthetically induced CO(2) uptake. The effect of CO(2) depletion on the acidity of the medium appeared to be mainly restricted to the first 15 minutes of exposure to light. Consequently, subsequent pH changes primarily reflected a constant net proton efflux. Acidification occurred in the dark, but rates of acidification increased in response to increased light approximately in parallel with changes in a concomitant net O(2) efflux. The results indicated that protoplasts could acidify the medium in response to nonphotosynthetic activity, but that photosynthesis mediated light stimulation of acidification.

Journal Article↗

PubMed1996

Memory, sleep, and dynamic stabilization of neural circuitry: evolutionary perspectives.

Some aspects of the evolution of mechanisms for enhancement and maintenance of synaptic efficacy are treated. After the origin of use-dependent synaptic plasticity, frequent synaptic activation (dynamic stabilization, DS) probably prolonged transient efficacy enhancements induced by single activations. In many "primitive" invertebrates inhabiting essentially unvarying aqueous environments, DS of synapses occurs primarily in the course of frequent functional use. In advanced locomoting ectotherms encountering highly varied environments, DS is thought to occur both through frequent functional use and by spontaneous "non-utilitarian" activations that occur primarily during rest. Non-utilitarian activations are induced by endogenous oscillatory neuronal activity, the need for which might have been one of the sources of selective pressure for the evolution of neurons with oscillatory firing capacities. As non-sleeping animals evolved increasingly complex brains, ever greater amounts of circuitry encoding inherited and experiential information (memories) required maintenance. The selective pressure for the evolution of sleep may have been the need to depress perception and processing of sensory inputs to minimize interference with DS of this circuitry. As the higher body temperatures and metabolic rates of endothermy evolved, mere skeletal muscle hypotonia evidently did not suffice to prevent sleep-disrupting skeletal muscle contractions during DS of motor circuitry. Selection against sleep disruption may have led to the evolution of further decreases in muscle tone, paralleling the increase in metabolic rate, and culminating in the postural atonia of REM (rapid eye movement) sleep. Phasic variations in heart and respiratory rates during REM sleep may result from superposition of activations accomplishing non-utilitarian DS of redundant and modulatory motor circuitry on the rhythmic autonomic control mechanisms. Accompanying non-utilitarian DS of circuitry during sleep, authentic and variously modified information encoded in the circuitry achieves the level of unconscious awareness as dreams and other sleep mentation.

Animals↗

PubMed2005

Comparing two evolutionary mechanisms of modern tRNAs.

All modern tRNA gene families have a high similarity in their primary structure, and share the same cloverleaf secondary structure and an inverted L tertiary structure, which provide the clues for the study of their origin and evolution. There are two important mechanisms of the tRNA sequences evolution. One is point mutation, another is complementary duplication method. Both of them are supported by some specific examples. To find out the superior one of the two mechanisms or find out the most suitable mechanism for modern tRNAs evolution, we constructed two types of networks, parallel and antiparallel networks, based on the two mechanisms respectively, and then compared the degree distribution and clustering coefficient of networks constructed by the tRNA sequences of the single anticodon group, single isoaccepting group, and the whole tRNAs group of the two types of networks. The result of the comparison seems consistent with the idea that modern tRNA sequences evolved primarily by the mechanism of complementary method, and point mutation is an important and indispensable auxiliary mechanism during the evolutionary event.

Base Pairing↗