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Results for “Continuous Evolution”

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PubMedDate not supplied

Minilaparoscopic versus laparoscopic cholecystectomy: a randomised controlled trial.

Since its introduction in 1987, the technique of cholecystectomy has continued to undergo evolution. Surgeons have reduced the port size and number or both to achieve improvement in postoperative pain control, rapid return to activity and better cosmetic results. Therefore, this study was done to compare the standard 4 port laparoscopic cholecystectomy (LC) with the 3 port laparoscopic cholecystectomy using a 5 mm telescope instead of 10 mm telescope (mini laparoscopic cholecystectomy - MLC). Forty patients were randomised to each group. Mean operating time, intraoperative and postoperative complications, mean period to resume walking, eating and return to normal activities and mean hospital stay were similar in the two groups. The level of postoperative pain was significantly lower in the MLC group. Patients who underwent MLC required a significantly lower dose of analgesics. In conclusion mini laparoscopic cholecystectomy is a feasible and safe procedure with less postoperative pain and better cosmesis and without increased complications.

Adolescent↗

PubMed1987

The clinical pharmacist in drug research and development. Pharmacodynamics.

Today, clinical pharmacists are involved in various types of pharmacodynamic research. Fellowship training programs encompassing research on pharmacodynamics, pharmacokinetics, and their relationships are becoming more prevalent. The training needs of future clinical pharmacist investigators require careful consideration, especially with regard to standards for fellowship programs and the evolving science of pharmacodynamic-pharmacokinetic modeling. Liability and legal issues as well as stable sources of funding for fellowships are current concerns of clinical pharmacist investigators. These issues notwithstanding, the prospect of continued growth and evolution of the clinical pharmacists' role in pharmacodynamic research looks bright.

Drug Therapy↗

PubMedDate not supplied

[Pulmonary radiographic changes in the course of otomastoid diseases with minimally symptomatic clinical evolution (in infants and young children)].

Otomastoiditis of infants and young children, masked in its evolution by antibiotics, continues to be increasingly met with. Diagnostic difficulties are caused by the paucity of the symptomatology in such cases. The present study included 111 cases of otomastoiditis admitted to the ORL Clinic for Children; routine X-ray of the lungs was performed. The results showed particular pulmonary alterations (interstitial design, diffuse or segmentary opacities, emphysema), without corresponding clinical pulmonary distress.

Child, Preschool↗

PubMed1993

Current studies on tooth enamel development in lower vertebrates.

The tooth enamel is a unique tissue in the human body on many characteristic features, in both morphological and developmental aspects. This tissue is widely distributed in the vertebrate world. This hard tissue is divided into two groups, mainly from the developmental feature. One is the enamel in the upper classes of the adult amphibian, called true or ectodermal enamel. The other mainly distributes in fish (both of osteichytyes and chondroichtyes), called enameloid or mesodermal enamel. Enameloid seen in fish has many characteristics compared with enamel, although enameloid after eruption is analog tissue to enamel. Many studies on the enameloid with a long history show its character. (1) The enameloid matrix is mainly composed of collagen fibrils to make thick bundles, most of which are interwoven in a complicated manner. (2) Mineralization of enameloid is initiated by the matrix vesicles similar to bone and dentine. (3) Growth of crystals does not stop the retention of their thin needle shape as with bone and dentine during mineralization, but finally begins to show a large hexagonal shape, as seen in the mature enamel of mammals. (4) Enameloid contains much fluoride and the fluoride exists as a fluoroapatite in enameloid. Many of the recent studies on this subject applied various histochemical methods, especially immunohistochemical studies, which show some evidence that enameloid and enamel might not be continuous in enamel evolution. It is now necessary to reconsider the enameloid from the phylogenetic aspect.

Amphibians↗

PubMed1993

Leishmaniasis.

Leishmanial infections include three major clinical syndromes: visceral, cutaneous, and mucosal leishmaniasis. Visceral leishmaniasis, usually due to Leishmania donovani, has received increasing attention in the United States because of the growing number of cases seen in AIDS patients and the occurrence of viscerotropic L. tropica disease among Persian Gulf war participants. Cutaneous leishmaniasis is a relatively benign disease caused by L. Mexicana and L. (Viannia) species in the New World, and L. major, L. tropica, and L. aethiopica in the Old World. Many of these cutaneous lesions are self-healing, and treatment recommendations vary and continue to undergo evolution and study. Mucosal disease, caused by Leishmania (V.) braziliensis, is difficult to diagnose as well as to treat. A practical approach to the clinical presentation, diagnostic measures, and some treatment options of these syndromes is presented in relation to specific case studies.

AIDS-Related Opportunistic Infections↗

PubMed1993

Pelvic relaxation involving the middle compartment.

Loss of pelvic support involving the 'middle compartment' is manifested by herniation through the central pelvic floor in proximity to the intersection of an imaginary line from the public symphysis to the coccyx with another from one ischial spine to opposite ischial spine. Loss of middle compartment support may exist in association with 'anterior compartment' defects, 'posterior compartment' defects, or both. The severity of middle compartment relaxation ranges from mild uterine descensus to total uterovaginal prolapse when the uterus is present. When the uterus has been removed, it may range from vaginal vault descent to total vaginal eversion and includes all grades of enterocele. Middle compartment defects are usually not isolated. The recent literature relevant to middle compartment defects consists primarily of additional reports on surgical management, including continued modification and evolution of surgical techniques. Larger surgical series with longer follow-up periods have been reported. Cadaveric and histologic studies have appeared which have added to the understanding of normal anatomy and the disruptions thereof, which can cause middle compartment defects. Sophisticated diagnostic imaging techniques have generated preliminary reports which are of interest.

Female↗

PubMed1993

Management of total nasopharyngeal stenosis following UPPP.

UPPP has emerged over the past decade as a surgical procedure to improve or possibly eliminate Obstructive Sleep Apnea. The procedure itself is not uniformly successful and the technique continues to undergo evolution. Most complications occur in the acute post-operative period and are not unusual. Late complications are seen much less frequently: less than 100 cases of severe nasopharyngeal stenosis have been reported. Several authors have previously identified this problem and have published "avoidance strategies" and we recommend that the UPPP surgeon be well aware of these pitfalls and the ways to avoid them. Stenosis repair using pharyngeal flaps should be the primary technique used to correct this problem. The radial forearm free flap provides the surgeon with another technique for repair of acquired nasopharyngeal stenosis in problem cases in which pharyngeal flap procedures have failed. As with any surgery, the surgeon must have a thorough understanding of the wound healing process.

Adult↗

PubMed1995

Achievements and new directions in continuous renal replacement therapies.

The evolution of renal replacement therapy has permitted the treatment of critically ill patients with acute renal failure. In intensive care settings, continuous renal replacement therapies have been shown to be better tolerated and clinically useful. Continuous hemofiltration is now performed with blood pumps and double-lumen venous catheters, thus avoiding the complications found in previous arteriovenous treatments. The use of countercurrent dialysate flow has overcome problems related to low treatment efficiency. High clearances can now be obtained during continuous hemodialysis or hemodiafiltration, and adequate blood purification can be achieved even in severely catabolic patients. New replacement solutions allow for a more effective correction of acidosis and electrolyte imbalances. Finally, newly designed machines permit continuous therapies while minimizing staff workload. Continuous therapies are today moving toward newer indications and applications. The ability to remove proinflammatory substances by filtration and/or adsorption has opened a series of potential indications. The concept that renal support and protection take place during hemofiltration suggests that very early use of this technique is desirable, even before the onset of oliguria or azotemia.

Acute Kidney Injury↗

PubMed2005

Phylogenetic reconstruction of ancestral character states for gene expression and mRNA splicing data.

BACKGROUND: As genomes evolve after speciation, gene content, coding sequence, gene expression, and splicing all diverge with time from ancestors with close relatives. A minimum evolution general method for continuous character analysis in a phylogenetic perspective is presented that allows for reconstruction of ancestral character states and for measuring along branch evolution. RESULTS: A software package for reconstruction of continuous character traits, like relative gene expression levels or alternative splice site usage data is presented and is available for download at http://www.rossnes.org/phyrex. This program was applied to a primate gene expression dataset to detect transcription factor binding sites that have undergone substitution, potentially having driven lineage-specific differences in gene expression. CONCLUSION: Systematic analysis of lineage-specific evolution is becoming the cornerstone of comparative genomics. New methods, like phyrex, extend the capabilities of comparative genomics by tracing the evolution of additional biomolecular processes.

Alternative Splicing↗

PubMedDate not supplied

Cellulose triacetate: another membrane for continuous renal replacement therapy.

The evolution of technology and biomaterials has permitted a parallel development of renal replacement therapies in the acute, critically ill patient. From the original continuous artero-venous hemofiltration method new techniques such as continuous veno-venous hemofiltration, hemodiafiltration and high-flux dialysis have been developed and are clinically used. Similar progress has been made with artificial membranes. We investigated the possibility of using a modified cellulosic membrane for continuous therapies, assessing the hydraulic characteristics and clearance performances of high-flux cellulose triacetate hemodiafilter (0.7 m2) in vitro and in vivo. The flowdynamic characteristics of the filter suggest its optimal use in veno-venous pump-drive techniques. Efficiency was excellent, with urea daily clearances as high as 50 liters or more. The high permeability and porosity of the membrane also increased the clearances of larger solutes such as creatinine and inulin. No side effects occurred during treatment and we conclude that cellulose triacetate may be considered a good alternative to synthetic membranes in continuous renal replacement therapies.

Acute Kidney Injury↗

PubMed2001

Initiation of therapy during primary HIV type 1 infection results in a continuous decay of proviral DNA and a highly restricted viral evolution.

A latent pool of HIV-1 is established early in memory CD4+ T lymphocytes and persists during antiretroviral therapy. Also, viral replication may continue in subjects despite undetectable viremia. However, it remains unclear whether this residual replication results in any significant sequence evolution. We were therefore interested in studying the viral evolution and HIV-1 DNA dynamics in subjects with primary infection receiving or not receiving early potent antiretroviral therapy. In 16 subjects, HIV-1 DNA load was monitored from 1 to 23 days, up to 1253 days, after onset of symptoms. Extensive sequential cloning and sequence analysis of the V3 region was performed in four subjects. In the treated subjects a continuous decline in the proviral load was found, corresponding to a half-life of about 6 months. As expected in newly infected individuals the founder virus populations showed high intrasubject sequence similarity. Also, a limited increase in the viral divergence was detected during the first 6 months in three treated subjects. Thereafter, no significant sequence changes were found despite analysis of a large number of clones. Our data thus suggest that early and successful therapy in compliant subjects with primary HIV-1 infection results in a highly restricted viral evolution and a decline in the proviral load close to the decay rate of human memory T lymphocytes.

DNA, Viral↗

PubMed1993

Reconstructing the evolution of mind.

Since Darwin, the idea of intellectual continuity has gripped comparative psychology. Psychological evolution has been viewed as the accumulation of gradual changes over time, resulting in an unbroken chain of mental capacities throughout the diversity of life. Some researchers have even maintained that no fundamental psychological differences exist among species. An alternative model argues that a rather profound new psychology related to mental state attribution may have evolved recently in the primate order. The author explores recent experimental research from chimpanzees, rhesus monkeys, and children that is consistent with this second model of psychological evolution. Drawing on the fields of developmental, comparative, and social psychology, as well as evolutionary and developmental biology, the author outlines a research agenda aimed at reconstructing the evolution of metacognition.

Animals↗

PubMedDate not supplied

Evolution of an operation.

The story of the origin of Matas' endoaneurysmorrhaphy with suggestions for maintaining or restoring arterial continuity and their gradual evolution into the technique of intrasaccular interpolation of grafts in managing aneurysms provides another example of the increased utility of an operative procedure by its modification and expansion.

Aneurysm↗

PubMed1994

Introns: evolution and function.

The debate continues on the issue of whether nuclear introns were present in eukaryotic protein-coding genes from the beginning (introns-early) or invaded them later in evolution (introns-late). Recent studies concerning the location of introns with respect to gene and protein structure have been interpreted as providing strong support for both positions, but the weight of argument is clearly moving in favour of the latter. Consistent with this, there is now good evidence that introns can function as transposable elements, and that nuclear introns derived from self-splicing group II introns, which then evolved in partnership with the spliceosome. This was only made possible by the separation of transcription and translation. If introns did colonize eukaryotic genes after their divergence from prokaryotes, the original question as to the evolutionary forces that have seen these sequences flourish in the higher organisms, and their significance in eukaryotic biology, is again thrown open. I suggest that introns, once established in eukaryotic genomes, might have explored new genetic space and acquired functions which provided a positive pressure for their expansion. I further suggest that there are now two types of information produced by eukaryotic genes--mRNA and iRNA--and that this was a critical step in the development of multicellular organisms.

Animals↗

PubMed1984

Serum concentration and peritoneal transfer of aluminum during treatment by continuous ambulatory peritoneal dialysis.

The evolution of the aluminum (A1) serum levels during a 2-year follow-up and the peritoneal transfer of A1 were studied in 22 patients treated by continuous ambulatory peritoneal dialysis (CAPD), using a dialysate with a very low A1 concentration (r = 0.25 - 0.30 mumoles/liter). Patients were divided in three groups. A transfer of A1 from the patient to the dialysate was observed in all patients. In group 1, patients exclusively treated by CAPD and who have never received aluminum-containing phosphate binders (ACPB), mean level (+/- SD) of serum A1 stabilized within a safe range (0.60 +/- 0.28 mumoles/liter). In group 2 the oral administration of ACPB in patients exclusively treated by CAPD induced a slow and progressive increase of A1 serum concentration despite the increase of the A1 excretion through the peritoneal route. In group 3, patients previously treated by hemodialysis and receiving ACPB, the high serum A1 levels observed before treatment by CAPD decreased rapidly on CAPD. A1 removal through the peritoneum was higher in group 3 than in group 2 despite serum A1 levels not statistically different in both groups. A1 removal through the peritoneum is mainly influenced by serum and dialysate A1 concentration. A1 body stores could play a role in the transfer of A1 through the peritoneum. Three cases of A1 poisoning due to the accidental use of a dialysate with a high A1 content are reported.

Adult↗

PubMed2001

Improving serum albumin levels in hemodialysis patients by a continuous quality improvement project.

Protein nutrition and serum albumins predict present and future mortality and morbidity. The North East Albuquerque Dialysis Center undertook a quality improvement project to improve serum albumin levels in hemodialysis patients. The dialysis facility's quality assurance team evolved into a continuous quality improvement team just before this project. The timeline and steps in this evolution are presented. The continuous quality improvement project process analysis, interventions, and outcome rates are also described. The project has resulted in a rate of less than or equal to 10% of hemodialysis patients with serum albumins less than 3.4 for the past 3 years.

Humans↗

PubMed2004

Drifting diffusion on a circle as continuous limit of a multiurn Ehrenfest model.

We study the continuous limit of a multibox Erhenfest urn model proposed before by the authors. The evolution of the resulting continuous system is governed by a differential equation, which describes a diffusion process on a circle with a nonzero drifting velocity. The short time behavior of this diffusion process is obtained directly by solving the equation, while the long time behavior is derived using the Poisson summation formula. They reproduce the previous results in the large M (number of boxes) limit. We also discuss the connection between this diffusion equation and the Schrödinger equation of some quantum mechanical problems.

Journal Article↗

PubMed2002

Hemagglutinin sequence clusters and the antigenic evolution of influenza A virus.

Continual mutations to the hemagglutinin (HA) gene of influenza A virus generate novel antigenic strains that cause annual epidemics. Using a database of 560 viral RNA sequences, we study the structure and tempo of HA evolution over the past two decades. We detect a critical length scale, in amino acid space, at which HA sequences aggregate into clusters, or swarms. We investigate the spatio-temporal distribution of viral swarms and compare it to the time series of the influenza vaccines recommended by the World Health Organization. We introduce a method for predicting future dominant HA amino acid sequences and discuss its potential relevance to vaccine choice. We also investigate the relationship between cluster structure and the primary antibody-combining regions of the HA protein.

Antibodies↗