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PubMed1995

Recording the sleep EEG with periorbital skin electrodes.

The aim of the study was to examine whether the typical changes of the EEG in the course of a sleep episode can be recorded by skin electrodes placed at the outer canthi of the eyes. In sleep recording from young, healthy subjects, the signals from the electro-oculogram (EOG, E1-A2) derivation and a central scalp EEG derivation (C3-A2) were compared. Sleep stage scores obtained separately from each of the two signals yielded highly corresponding values with the exception of stages 2 and 4, for which there were discrepancies. Both signals were subjected to spectral analysis to compare the spectra and their evolution during sleep. An automated detection routine served to identify and eliminate epochs contaminated by eye movement potentials. The typical time course of EEG slow-wave activity (SWA; power density in the 0.75-4.5 Hz range) could be derived from both signals with only minor differences between the data sets. However, compared to the EEG spectra, power density of the EOG spectra was attenuated in frequencies higher than 2 Hz and the typical changes in the spindle frequency range were not evident. The results show that the major sleep parameters as well as the dynamics of SWA can be reliably determined from signals recorded from periorbital skin electrodes.

Adult↗
PubMed1991

Management of the hypotonous cyclodialysis cleft.

Authoritative experience in the management of hypotonous cyclodialysis clefts is difficult to obtain because of their rarity. In this study, the authors describe nine patients with hypotonous cyclodialyses clefts: six patients were treated successfully with argon laser photocoagulation to the cleft surfaces; in one patient, cleft diathermy was used to seal an incompletely closed cleft after a single argon laser treatment; one patient responded to conservative management; another patient did not require treatment. Four cases followed ocular trauma and five occurred after extracapsular cataract extraction and posterior chamber intraocular lens implantation. In three patients, the anterior chamber was too shallow to permit gonioscopy; sodium hyaluronate (Healon) was used to reform the anterior chamber, to delineate the extent of the cyclodialysis cleft, and to provide maximal access for the argon laser treatment. In another patient, laser cleft consolidation was successful only after fully opening the cleft with sodium hyaluronate. The evolution of the laser photocoagulation technique used by the authors is described. Laser cyclodialysis cleft consolidation can be repeated easily and safely. The authors recommend argon laser photocoagulation as the primary management approach. Intracameral viscoelastic agents are useful adjuncts. The complications of cleft lasering are minor, although a hypertensive episode commonly occurs in the early postoperative period as the cleft closes. Major intraocular surgeries usually can be avoided.

Adult↗
PubMed2003

Clinical management of HCV carriers with normal aminotransferase levels.

An ad hoc committee appointed by the Italian Association for the Study of the Liver (AISF) proposed these Practice Guidelines for the management of HCV carriers with persistently normal aminotransferase levels. Only stringent ALT determinations will make it possible to distinguish these subjects from those in temporary biochemical remission. The overall prevalence in Italy has been estimated between 1.5 and 10.6%. HCV RNA quantitation and genotype determination are not predictors of the presence and severity of liver damage nor correlate with the outcome of the disease, and should not be used in clinical practice for the management and surveillance of HCV carriers with normal ALT. Only a minority of HCV carriers with normal ALT levels show a normal morphological picture (true 'healthy carriers'). Disease activity is mild in most cases; fibrosis is generally mild and cirrhosis is very rare. Histological activity, as monitored by sequential liver biopsies, seems to have very slow evolution. HCV carriers should not undergo liver biopsy on a routine basis. Liver biopsy can be reasonably proposed only in selected cases. Until the results of studies with PEG interferon plus ribavirin are available, HCV carriers should not receive antiviral treatment outside controlled experimental studies.

Alanine Transaminase↗
PubMed1994

The D-E region of the D1 protein is involved in multiple quinone and herbicide interactions in photosystem II.

The region between helices D and E (D-E region) of the D1 protein of photosystem II (PSII) is exposed at the stromal side of the photosynthetic membrane, contains the secondary plastoquinone (QB) binding niche, and is involved in processes at the reducing side of PSII. The role of the D-E region was studied in 27 site-directed mutants generated in the psbAII gene of the cyanobacterium Synechocystis sp. PCC 6803. The photochemical performance of the modified PSII reaction centers was assessed with respect to photoautotrophic growth, oxygen evolution, fluorescence induction, and herbicide inhibition. A few mutations, located at positions presumably involved in essential interactions in the QB binding niche, greatly interfered with PSII performance. On the other hand, mutations in the presumptive loop region between helices D and de resulted in relatively minor effects, indicating a flexible region not critical for photochemical function. Indeed, although more than 80% of the D-E region is phylogenetically invariant, the bulk of the mutations affected the measured parameters only moderately. The significance of the conserved residues appears to be in subtle interactions that optimize the thermodynamic balance between some of the redox components of PSII, as indicated by mild changes in the steady state fluorescence. Many mutations modified tolerances to PSII herbicides. The dispersion of these mutations throughout the D-E region indicates the complex nature of the interactions, direct and indirect, affecting herbicide binding in the QB niche. Mutation of codons Ser221 and Ser222 to Leu221 and Ala222 revealed a new location coordinating the herbicide diuron in the D1 protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1999

Chromosomal localization of 5S rDNA genes in Leporinus fish (Anostomidae, Characiformes).

The large 45S rDNA chromosome sites have often been analyzed in fish. In contrast, little is known about the 5S genes in this animal group. In the genus Leporinus, the NOR chromosomal location has been shown to be very diverse. In the present work, chromosome mapping of 5S rDNA in three anostomids, Leporinus elongatus, L. obtusidens and L. friderici, is investigated using fluorescence in-situ hybridization (FISH) with PCR-obtained 5S probes and primed in-situ labeling (PRINS). Major 5S rDNA chromosomal sites were found to be subterminally located in a small metacentric pair, while minor ones were detected near the centromeric region of a medium-sized submetacentric pair in all studied species. The 5S rDNA genes were not associated with the NORs or sex chromosomes. A highly conserved chromosomal location of these genes appears to characterize the karyotype evolution of this fish group.

Animals↗
PubMed1994

The circumstellar environment of IRAS 05338-0624.

Millimeter continuum and spectral line observations with 10", 30", and 60" resolution are used to characterize the structure and chemistry of the gas around the young, embedded star, IRAS 05338-0624. On arcminute scales, emission from dense gas tracers outline an isolated condensation centered on the IRAS source position. The condensation is characterized by a size of approximately 60", a density of 2 x 10(5) cm-3, and a virial mass of 40 M solar. Interferometric CS J = 2-1 observations show two peaks, one toward the continuum peak and the other toward a position 14" west and 8" south. Single-dish maps of SO, CH3OH, and SiO show pronounced wing emission to the west of the IRAS source, which interferometer observations reveal to be a compact region of outflow activity. CS emission as redshifted and blueshifted velocities reveals a bipolar outflow oriented with a position angle of 45 degrees, while SiO emission appears to be tracing a fast shock interaction region at the CS red-lobe peak, 14" west and 8" south of the IRAS source. Finally, H13CO+ emission traces clumps of quiescent gas toward the IRAS source and adjacent to the blue lobe of the outflow. Column densities and molecular fractional abundances are derived to explore the interaction between the surrounding condensation and the young stellar object. We find evidence for gas phase depletions within the overall condensation in several gas tracers (CO, CS, HCN, SO) but not in the region immediately around the young stellar object. Enhanced abundances of SO, CH3OH, and SiO (by factors of 4, >100, >1000, respectively) are observed in the shocked gas; these enhancements may be explained in terms of a nondissociative shock liberating mantle materials that contain some amount of refractory materials, a moderate velocity dissociative shock in which only minor sputtering of Si occurs, or a shock that impacts surrounding material with a range of speeds.

Astronomy↗
PubMed2004

Sexual function after rectal excision.

BACKGROUND: Rectal excision is associated with a risk of autonomic nerve damage and associated sexual dysfunction (SD). The evolution of our understanding of the anatomy and physiology of sexual function together with continual refinement of surgery for both benign and malignant disease has led to a decrease in the incidence of SD after rectal surgery. A knowledge of the degree of risk of postoperative SD is important both for the patient and as a benchmark for audit of individual colorectal practice. METHODS: The available literature on the anatomy, physiology and surgical aspects of this topic has been researched through the Medline database. The more recently available data are reviewed in the context of the historical evolution of surgery for benign and malignant rectal disease. RESULTS AND CONCLUSIONS: In the best hands, permanent impotence occurs in less than 2% of patients following restorative proctocolectomy and at a similarly low rate after proctocolectomy and ileostomy. Isolated ejaculatory dysfunction is also numerically a minor problem post operation for benign disease. Patient age is the most important predictor of SD after surgery for rectal cancer. The incidence of permanent impotence remains high (>40%) after abdomino-perineal excision of the rectum (APE) but the continued decline in the use of this operation in favour of low anterior resection (LAR), which carries about half the risk of impotence compared to sphincter ablating surgery, is likely to have resulted in a fall in the absolute number of patients rendered impotent as a result of rectal cancer surgery. Anatomical dissection of the pelvis with preservation of the named autonomic fibres results in a low and predictable rate of sexual morbidity. Surgeons could profitably spend more time with their patients discussing the possible effects of surgery on sexual function. Further research is required to determine the effects of adjuvant therapy for rectal cancer on sexual function.

Autonomic Nervous System Diseases↗
PubMed2003

Infestation and distribution of the mite Varroa destructor in colonies of Africanized bees.

Whereas in several parts of the world varroa is the major pest affecting apiculture, in others the parasite is unknown to many beekeepers because its damage to bees is minor. The impact of the mite Varroa destructor is related to the climatic conditions and the races of Apis mellifera bees in each region where the pest exists. In the present study, the current level of infestation by the mite was assessed to determine the evolution of the pest in Africanized bee colonies in Southern Brazil. This level of infestation was considered low: approximately two mites per one hundred adult bees. This result is similar to that obtained for the same apiary almost five years ago and for others distributed in various regions of Brazil. In the present study, we also estimated the total varroa population and its distribution among brood and adults in each bee colony.

Animals↗
PubMed1993

School drug education programming: in search of a new direction.

School drug abuse prevention programs represent an enormous educational resource. Recent perceptions of an epidemic of drug abuse among the nation's youth have fueled the escalation in expenditures for drug prevention programming. An important question that needs to be addressed concerns whether broad ranging drug education efforts directed at all public and private school students are efficient and effective uses of available resources? After a brief survey of the evolution of drug education programming in the U.S., this article examines recent longitudinal research regarding the antecedents of drug abuse among young people. Based on this research, suggestions are made for a new approach to drug education programs which would direct intensive interventions at the minority of youth who are identifiable in early childhood as particularly susceptible to problems with drug abuse.

Adolescent↗
PubMed1991

Structure and diversity of class I antigen presenting molecules in the mouse.

Sequence comparisons among class I genes provide insight into the nature and origins of diversity in the human and mouse MHC. The profiles of diversity among alleles and between different loci indicate that genetic interactions among class I genes generate sequence diversity in both species. Humans and mice differ in the extent that sequence transfer occurs between loci. In mice, sequences encoding the antigen binding domain show little evidence of locus specificity. A series of mouse class I mutants have been analyzed, providing strong evidence that interlocus gene conversion plays a significant role in the exchange of sequences among class I genes. A similar process is suspected in human class I and both mouse and human class II genes. However, the transfer of sequence among genes in these groups appears to occur predominantly between alleles and only to a minor extent between loci.

Amino Acid Sequence↗
PubMed1996

Faconi anemia and bone marrow clonal chromosome abnormalities.

Clonal chromosome abnormalities were detected in bone marrow cells of 20 patients with Fanconi anemia investigated at various stages of the disease. Two presented with acute leukemia, six with myelodysplastic syndrome, and 12 had minor or no morphological abnormalities of hematopoietic cells. Abnormalities of chromosome 7 were detected in nine patients (monosomy, isochromosome, or other structural rearrangement), and chromosome 1 was rearranged in four. The types and the significance of clonal chromosome abnormalities which may be present without apparent evolution toward acute leukemia or myelodysplastic syndrome in Fanconi anemia patients are discussed.

Adolescent↗
PubMed1998

[Isolated fracture of the ulnar diaphysis, from plate osteosynthesis to intramedullary nailing].

PURPOSE OF THE STUDY: The authors report a study from a series of 113 adults treated by osteosynthesis in a seven year period, for an adult isolated ulnar shaft fracture by osteosynthesis. These patients were divided into two groups: 57 patients treated by open reduction and AO plate fixation (group n(o) 1), and 56 patients operated by percutaneous intramedullary nailing, according to Böhler technique, with a simple Kirschner pin suited into the medullary canal (group n(o) 2). MATERIAL AND METHODS: For this ulnar fracture, the proportion of men and women was equal, with an average age of 37 years, predominant on the left limb (61 per cent). The most common cause was direct trauma (71 per cent): Böhler's "parry fracture", followed by traffic accidents (14 per cent), and 6 per cent by falls. We never found, in this series, indirect fractures by fall on the hand palm, and never clinical or radiological objective signs for a suspected lesion of the proximal and distal joints. Both operative procedures are described, with a particular emphasis on the simplicity of the nailing technique. No immobilization, of any kind, was applied, and patients were allowed to start full movements of the wrist and elbow, immediately after surgery. RESULTS: There were no early post operative complications, but great differences in the evolution between both groups. In group n(o) 1, there was a 29.8 per cent complication rate, 47 per cent of this was considered as "major" including osteomyelitis, non union, plate breakage, screw loosening, refractures. Patients in group n(o) 2, suffered only a few "minor" complications. Functional and anatomical results were also better in group 2 with earlier return to work. DISCUSSION: Isolated fracture of the ulnar shaft in the adult is known as a problematic fracture which needs long time to unite and often ends in non union. If opinion varies between plaster or internal fixation, we have abandoned the conservative treatment for the osteosynthesis. In order to demonstrate that intramedullary nailing technique gives a "sufficient" fixation, the authors pointed out the biomechanical importance of soft tissues structure preservation. CONCLUSION: Percutaneous intramedullary nailing of isolated ulnar shaft fractures in adult, is a simple and inexpensive technique, which gives predictable bone union, without particular complication and without drawbacks of other internal fixation techniques.

Adolescent↗
PubMed1993

Convergent evolution of similar enzymatic function on different protein folds: the hexokinase, ribokinase, and galactokinase families of sugar kinases.

Kinases that catalyze phosphorylation of sugars, called here sugar kinases, can be divided into at least three distinct nonhomologous families. The first is the hexokinase family, which contains many prokaryotic and eukaryotic sugar kinases with diverse specificities, including a new member, rhamnokinase from Salmonella typhimurium. The three-dimensional structure of hexokinase is known and can be used to build models of functionally important regions of other kinases in this family. The second is the ribokinase family, of unknown three-dimensional structure, and comprises pro- and eukaryotic ribokinases, bacterial fructokinases, the minor 6-phosphofructokinase 2 from Escherichia coli, 6-phosphotagatokinase, 1-phosphofructokinase, and, possibly, inosine-guanosine kinase. The third family, also of unknown three-dimensional structure, contains several bacterial and yeast galactokinases and eukaryotic mevalonate and phosphomevalonate kinases and may have a substrate binding region in common with homoserine kinases. Each of the three families of sugar kinases appears to have a distinct three-dimensional fold, since conserved sequence patterns are strikingly different for the three families. Yet each catalyzes chemically equivalent reactions on similar or identical substrates. The enzymatic function of sugar phosphorylation appears to have evolved independently on the three distinct structural frameworks, by convergent evolution. In addition, evolutionary trees reveal that (1) fructokinase specificity has evolved independently in both the hexokinase and ribokinase families and (2) glucose specificity has evolved independently in different branches of the hexokinase family. These are examples of independent Darwinian adaptation of a structure to the same substrate at different evolutionary times. The flexible combination of active sites and three-dimensional folds observed in nature can be exploited by protein engineers in designing and optimizing enzymatic function.

Amino Acid Sequence↗
PubMed2004

Evolution and phylogenetic utility of CAD (rudimentary) among Mesozoic-aged Eremoneuran Diptera (Insecta).

We sequenced nearly the entire carbomoylphosphate synthase (CPS) domain of CAD, or rudimentary, (ca. 4 kb) from 29 species of flies representing all major clades within Eremoneura, or higher flies, and several orthorrhaphous brachyceran outgroups. We compared these sequences with orthologs from Anopheles gambiae and Drosophila melanogaster to assess structure, compositional bias, and phylogenetic utility. CAD is large (6.6+ kb), complex (comprised of three major and myriad minor functional domains) and relatively free of introns, extreme nucleotide bias (except third codon positions), and large hypervariable regions. The CPS domain possesses moderate levels of nonsynonymous divergence among taxa of intermediate evolutionary age and conveys considerable phylogenetic signal. Phylogenetic analysis of CPS sequences under varying methods and assumptions resulted in well-resolved, strongly supported trees concordant with many traditional ideas about higher dipteran phylogeny and with prior inferences from 28S rDNA. The most robustly supported major eremoneuran clades were Cyclorrhapha, Platypezoidea, Eumuscomorpha, Empidoidea, Atelestidae, Empidoidea exclusive of Atelestidae, Hybotidae s.l., Microphoridae+Dolichopodidae, and Empididae s. str. Because CAD is ubiquitous, apparently single copy (at least within holometabolous insects), readily obtained from several insect orders using primers described herein, and exhibits considerable phylogenetic utility, it should have wide applicability in insect molecular systematics.

Animals↗
PubMed1981

[Biochemistry of the evolutive cycle of Triatoma infestans (vinchuca). V. Volatile fatty acids emission].

The composition of the volatile fatty acids emitted by Triatoma infestans of both sexes was studied. They were constituted by a mixture of the acids acetic, propionic, butyric, isobutyric, isovaleric, valeric and traces of isohexanoic and octanoic. Acetic acid was predominant followed by isobutyric and then by propionic acid. The other fatty acids are minor constituents. When acetic acid was discounted, the remaining composition was similar to the volatile fatty acid distribution pattern of Brindley gland. Both sexes showed a similar composition and therefore discard the possibility that they may function as sexual pheromones.

Acetates↗
PubMed2005

A high-resolution whole-genome cattle-human comparative map reveals details of mammalian chromosome evolution.

Approximately 3,000 cattle bacterial artificial chromosome (BAC)-end sequences were added to the Illinois-Texas 5,000-rad RH (RH, radiation hybrid) map. The BAC-end sequences selected for mapping are approximately 1 Mbp apart on the human chromosomes as determined by blastn analysis. The map has 3,484 ordered markers, of which 3,204 are anchored in the human genome. Two hundred-and-one homologous synteny blocks (HSBs) were identified, of which 27 are previously undiscovered, 79 are extended, 26 were formed by previously unrecognized breakpoints in 18 previously defined HSBs, and 23 are the result of fusions. The comparative coverage relative to the human genome is approximately 91%, or 97% of the theoretical maximum. The positions of 64% of all cattle centromeres and telomeres were reassigned relative to their positions on the previous map, thus facilitating a more detailed comparative analysis of centromere and telomere evolution. As an example of the utility of the high-resolution map, 22 cattle BAC fingerprint contigs were directly anchored to cattle chromosome 19 [Bos taurus, (BTA) 19]. The order of markers on the cattle RH and fingerprint maps of BTA19 and the sequence-based map of human chromosome 17 [Homo sapiens, (HSA) 17] were found to be highly consistent, with only two minor ordering discrepancies between the RH map and fingerprint contigs. The high-resolution Illinois-Texas 5,000-rad RH and comparative maps will facilitate identification of candidate genes for economically important traits, the phylogenomic analysis of mammalian chromosomes, proofing of the BAC fingerprint map and, ultimately, aid the assembly of cattle whole-genome sequence.

Animals↗
PubMed1999

Th1 predominance and perforin expression in minor salivary glands from patients with primary Sjögren's syndrome.

Objectives of this study were to examine the cytokine and perforin mRNA expression in minor salivary glands from patients with primary Sjögren's syndrome (pSS), searching for possible correlation with clinical parameters and to identify the dominant cytokine pattern in the different groups. Oral mucosa biopsy samples from 42 pSS patients were studied. Total RNA was analysed by normalized RT-PCR using oligo-dT as the RT primer and IL-2, IFN-gamma, IL-12, IL-18, IL-4, IL-10, TGF-beta, TNF-alpha and perforin-specific primers for amplification. Results were analysed taking into account: (1) biopsy grade I to IV (Chisholm's classification); (2) diagnosis of either definite pSS (n=30) or probable pSS (n=12), following the European classification criteria (ECC), and (3) length of disease evolution from the beginning of symptoms to the time of biopsy, using an arbitrary cut-off point of 12 months. This studied showed that Th1-related cytokines (IL-2, IFN-gamma, IL-12, IL-18, TNF-alpha) and perforin were present in most samples. IL-4 (Th2) was totally absent but other Th2 and regulatory cytokines (IL-10, TGF-beta) were detected in the majority of samples. No significant differences were found between definite and probable pSS nor between grades II, III, IV and fibrous tissue biopsies. A statistically significant increase of IL-2 (P=0.012) and IFN-gamma (P=0.019) was observed in samples from patients with longer disease evolution, whereas the two Th1-inducer cytokines IL-12 and IL-18 were equally and highly expressed in all samples. In conclusion, a predominant Th1 pattern of cytokines was observed in all pSS samples, irrespective of biopsy classification. In addition, a significant increase of Th1 cytokine expression frequency was associated with longer disease evolution.

Adult↗
PubMed2006

Emergence of the universal genetic code imprinted in an RNA record.

The molecular basis of the genetic code manifests itself in the interaction of the aminoacyl-tRNA synthetases and their cognate tRNAs. The fundamental biological question regarding these enzymes' role in the evolution of the genetic code remains open. Here we probe this question in a system in which the same tRNA species is aminoacylated by two unrelated synthetases. Should this tRNA possess major identity elements common to both enzymes, this would favor a scenario where the aminoacyl-tRNA synthetases evolved in the context of preestablished tRNA identity, i.e., after the universal genetic code emerged. An experimental system is provided by the recently discovered O-phosphoseryl-tRNA synthetase (SepRS), which acylates tRNA(Cys) with phosphoserine (Sep), and the well known cysteinyl-tRNA synthetase, which charges the same tRNA with cysteine. We determined the identity elements of Methanocaldococcus jannaschii tRNA(Cys) in the aminoacylation reaction for the two Methanococcus maripaludis synthetases SepRS (forming Sep-tRNA(Cys)) and cysteinyl-tRNA synthetase (forming Cys-tRNA(Cys)). The major elements, the discriminator base and the three anticodon bases, are shared by both tRNA synthetases. An evolutionary analysis of archaeal, bacterial, and eukaryotic tRNA(Cys) sequences predicted additional SepRS-specific minor identity elements (G37, A47, and A59) and suggested the dominance of vertical inheritance for tRNA(Cys) from a single common ancestor. Transplantation of the identified identity elements into the Escherichia coli tRNA(Gly) scaffold endowed facile phosphoserylation activity on the resulting chimera. Thus, tRNA(Cys) identity is an ancient RNA record that depicts the emergence of the universal genetic code before the evolution of the modern aminoacylation systems.

Aminoacylation↗