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Results for “Continuous Evolution”

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PubMed1999

Antigen-driven CD4+ T cell and HIV-1 dynamics: residual viral replication under highly active antiretroviral therapy.

Antigen-induced stimulation of the immune system can generate heterogeneity in CD4+ T cell division rates capable of explaining the temporal patterns seen in the decay of HIV-1 plasma RNA levels during highly active antiretroviral therapy. Posttreatment increases in peripheral CD4+ T cell counts are consistent with a mathematical model in which host cell redistribution between lymph nodes and peripheral blood is a function of viral burden. Model fits to patient data suggest that, although therapy reduces HIV replication below replacement levels, substantial residual replication continues. This residual replication has important consequences for long-term therapy and the evolution of drug resistance and represents a challenge for future treatment strategies.

Anti-HIV Agents↗

PubMed2004

Pneumocephalus in neonatal meningitis: diffuse, necrotizing meningo-encephalitis in Citrobacter meningitis presenting with pneumatosis oculi and pneumocephalus.

UNLABELLED: OBJECTIVE/PATIENT: Gas-containing encephalitis is rarely associated with neonatal meningitis. We report a case of a 19-day-old baby who presented with a rapid onset of septic shock complicated by progressively increasing gas accumulation within the brain and anterior chamber of the eye. We describe the evolution of the clinical picture and the management. INTERVENTIONS: Ventilatory support, fluid resuscitation, and continuous venovenous hemofiltration were provided in view of multiple system failure. Despite effective antibiotic therapy and supportive management, the patient died with worsening accumulation of gas within the brain, resulting in brainstem death. RESULTS: Computed tomographic images were characteristic of diffuse necrotizing meningo-encephalitis. Postmortem examination showed friable brain tissue with venous infarction and extensive gas accumulation. Citrobacter koseri was identified from the blood and cerebrospinal fluid cultures. CONCLUSION: This case re-emphasises the importance of C. koseri as both a community-acquired and nosocomial neonatal pathogen. Radiologic evidence suggestive of diffuse necrotizing meningo-encephalitis in combination with pneumocephalus and pneumatosis oculi in Citrobacter infections has never been described before. Diagnostic imaging with computed tomographic scanning of the brain and initiation of broad-spectrum antibiotics with good penetration into cerebrospinal fluid are indicated as soon as infection with Citrobacter species is suspected clinically, with appearance of pneumatosis oculi as a rare, late finding.

Citrobacter koseri↗

PubMed2001

Coexistence of large amplitude stationary structures in a model of reaction-diffusion system.

The two-variable reaction-diffusion model of a chemical system describing the spatiotemporal evolution to large amplitude stationary periodical structures in a one-dimensional open, continuous-flow, unstirred reactor is investigated. Numerical solutions show that the structures are generated by divisions of the traveling impulse and its stopping at the boundary of the system. Analyses of projections of numerical solutions on the phase plane of two variables elaborated in the present paper allow qualitative explanation of the results. The coexistence of the large amplitude stationary periodical structures is shown. A number of coexisting structures grows strongly with increasing length of the reactor and may be as large as one wishes. The relationship of these results to biological systems is stressed.

Journal Article↗

PubMed2002

Lattice Boltzmann simulation of chemical dissolution in porous media.

In this paper, we develop a lattice Boltzmann model for simulating the transport and reaction of fluids in porous media. To simulate such a system, we account for the interaction of forced convection, molecular diffusion, and surface reaction. The problem is complicated by the evolution of the porous media geometry due to chemical reactions, which may significantly and continuously modify the hydrologic properties of the media. The particular application that motivates the present study is acid stimulation, a common technique used to increase production from petroleum reservoirs. This technique involves the injection of acid (e.g., hydrochloric acid, HCl, acetic acid, HAc) into the formation to dissolve minerals comprising the rock. As acid is injected, highly conductive channels or "wormholes" may be formed. The dissolution of carbonate rocks in 0.5M HCl and 0.5M HAc is simulated with the lattice Boltzmann model developed in this study. The dependence of dissolution process and the geometry of the final wormhole pattern on the acid type and the injection rate is studied. The results agree qualitatively with the experimental and theoretical analyses of others and substantiate the previous finding that there exists an optimal injection rate at which the wormhole is formed as well as the number of pore volumes of the injected fluid to break through is minimized. This study also confirms the experimentally observed phenomenon that the optimal injection rate decreases and the corresponding minimized number of pore volumes to break through increases as the acid is changed from HCl to HAc. Simulations suggest that the proposed lattice Boltzmann model may serve as an alternative reliable quantitative approach to study chemical dissolution in porous media.

Journal Article↗

PubMed2006

Addiction: a journal and its Invisible College.

UNLABELLED: PROVENANCE: This paper derives from a lecture given before the Society for the Study of Addiction in November 2004, on the author's retirement from the position of Editor-in-Chief of Addiction, one of the Society's journals. AIM: To identify the live processes which have influenced the journal's evolution since its foundation in 1884. CONCLUSIONS: Over the 120-year period a strong, continuing historical thread has been the fluctuating success of the journal's engagement with its 'Invisible College', the community which it seeks to serve. It is argued that the journal's future success will depend on its capacity to explore and nurture further this two-way relationship. Addiction is a journal with an active and clearly articulated, multiple vision of it purpose, and this vision is outlined. It dares to try to influence its future with the authority so to do rooted in its ability to reflect the aspirations and concerns of its readers. It is 'a journal of the second kind'.

Behavior, Addictive↗

PubMed1990

Nucleolar organizer regions in gastric carcinoma and its precursor stages.

A silver technique for nucleolar organizer regions (AgNOR) was applied to sections from 156 gastric biopsies and gastrectomy specimens. These included normal controls, normal gastric mucosa from carcinoma-bearing stomachs, intestinal metaplasia types I and III, dysplasia and carcinoma. AgNOR counts gradually increased from normal, through intestinal metaplasia, to carcinoma. This finding supports the chronic atrophic gastritis-intestinal metaplasia-dysplasia-carcinoma sequence concept for gastric carcinogenesis. Normal gastric mucosa was different from all lesions, including normal mucosa from carcinoma-bearing stomachs. Significantly higher AgNOR counts were observed in tumours compared to all other lesions except dysplasia. Dysplasia differed from intestinal metaplasia type I but not from type III. Eighty-five per cent of metaplasia cases overlapped with carcinoma and 19% with normal controls. The spread of AgNOR values in intestinal metaplasia reinforces the concept that this lesion is a heterogeneous entity reflecting a dynamic and continuous process. The AgNOR technique may contribute to the assessment of the stage of evolution of 'borderline' lesions.

Biopsy↗

PubMedDate not supplied

Early treatment and prognosis of epilepsy.

Community-based studies and our own prospective hospital-based studies suggest that the prognosis for control of epilepsy is more favorable than previously reported. Approximately three quarters of newly diagnosed patients can enter prolonged remission on currently available medication. The first 2 years of treatment are crucial in determining the subsequent course of epilepsy. The longer seizures continue, the less likely they are to be controlled. Factors that contribute to the evolution of chronic epilepsy are the presence of brain lesions, neuropsychiatric handicaps, and poor compliance. Early effective treatment may also be important in preventing the evolution of chronic epilepsy. Recent studies have not revealed any significant differences in efficacy between the major antiepileptic drugs, and the choice of drug will therefore be influenced by costs and side effects, especially cognitive and behavioral effects. The majority of patients with a single unprovoked tonic-clonic seizure go on to develop epilepsy. Studies are required to evaluate the need for and outcome of therapy in such patients. Information about the natural history of untreated epilepsy, and also the possible influence of drug therapy on the prospects for spontaneous remission, is lacking.

Adolescent↗

PubMed1997

Follow-up results of different treatment programs for obese children.

OBJECTIVE: Many approaches have been tried in order to tackle the problem of obesity in children, but most of them have failed to achieve long-term weight loss. Cognitive behaviour therapy tends to predict good prospects. So far, no studies have investigated the surplus value of introducing a "healthy-eating" lifestyle program instead of a strict diet prescription, in combination with the principles of cognitive behaviour therapy. Therefore, a new program was designed. The second aim of the study was to evaluate the impact of different forms of therapeutic contact. SUBJECTS AND METHODS: The obese group consisted of 205 children seeking treatment, and a control group of 54 obese school children. The effects of the program were evaluated by means of a pre-test/post-test design with a 1-y follow-up. Subjects were assigned to different therapeutic conditions: group therapy, individual therapy, summer camp or "advice in one session". RESULTS: A progressive and significant loss of weight for all therapeutic conditions was noticeable. The reduction continued at least 6 months after completing therapy. The control group, however, showed weight evolution in the opposite sense. CONCLUSIONS: A replication of the positive effect of CBT was found in a broad sample of clinically obese children, even without strict diet prescription. Our hypothesis that group approach will result in a better outcome is borne out.

Adolescent↗

PubMed1987

Stress, competence, and development: continuities in the study of schizophrenic adults, children vulnerable to psychopathology, and the search for stress-resistant children.

The evolution of an ongoing research study into stress-resistant factors in children is traced from the early work on adult schizophrenia through the identification of risk factors in children vulnerable to stress. Future directions for the research are explored, including the necessity for defenses against possible politicization of the findings.

Child↗

PubMed2006

Streamlining and simplification of microbial genome architecture.

The genomes of unicellular species, particularly prokaryotes, are greatly reduced in size and simplified in terms of gene structure relative to those of multicellular eukaryotes. Arguments proposed to explain this disparity include selection for metabolic efficiency and elevated rates of deletion in microbes, but the evidence in support of these hypotheses is at best equivocal. An alternative explanation based on fundamental population-genetic principles is proposed here. By increasing the mutational target sizes of associated genes, most forms of nonfunctional DNA are opposed by weak selection. Free-living microbial species have elevated effective population sizes, and the consequent reduction in the power of random genetic drift appears to be sufficient to enable natural selection to inhibit the accumulation of excess DNA. This hypothesis provides a potentially unifying explanation for the continuity in genomic scaling from prokaryotes to multicellular eukaryotes, the divergent patterns of mitochondrial evolution in animals and land plants, and various aspects of genomic modification in microbial endosymbionts.

Animals↗

PubMed1981

Exercise hemodynamics 1 month, 2 months and 1 year after myocardial infarction: prognostic considerations.

Sequential electrocardiographic and hemodynamic changes were studied at rest and during symptom-limited bicycle exercise in oligo-asymptomatic patients after myocardial infarction (MI). The exercise tests were performed after the acute episode on days 29 +/- 4 (E1) and 62 +/- 6 (E2) in 128 patients; on days 37 +/- 5 (E1) and 380 +/- 4 (E3) in 97 patients; on days 37 +/- 4 (E1), 72 +/- 6 (E2) and 394 +/- 30 (E3) in 44 patients. All patients underwent an intensive physical training during the second month after the MI. All groups showed a significant increase in work capacity and reduction in heart rate and rate-pressure product at similar work load (E2 and E3 vs. E1). These changes were independent from the level of exercise pulmonary wedge pressure (E-PWP). On the average a reduction of PWP was observed in more compromised patients after training, which became more marked at 1 year. At similar work load 1 year after MI the cardiac index reduced in less compromised patients (E1-PWP greater than 30 mm Hg) while it remained unchanged in patients with E1-PWP less than or equal to 30 mm Hg. Continuation or interruption of the physical training did not seem to affect the hemodynamic evolution. The incidence of ST-segment depression did not change from 1 month to 2 months and 1 year after MI, while both incidence and amount of ST-segment elevation significantly decreased and the sum of R-wave voltages in 12 lead ECG increased at 1 year. In conclusion, oligo-asymptomatic patients, trained and treated by drugs, trend to improve in the first year post-infarct.

Adult↗

PubMed2005

Clinical lactation practice: 20 years of evidence.

Lactation consultants depend on a vast multidisciplinary knowledge base to support their practices. To coincide with the 20-year anniversary of the International Lactation Consultant Association, the authors sought to highlight the knowledge base to demonstrate how practice has been affected. Using standard databases, they extracted English-language scientific literature related to breastfeeding and maternal and infant health outcomes; factors associated with breastfeeding initiation, exclusivity, and duration; lactation physiology; common breastfeeding challenges; breastfeeding practices within vulnerable populations; health professional support of breastfeeding; and breastfeeding practices in developing countries of Africa. Summaries of research are provided to demonstrate scientific method and knowledge evolution. As the knowledge of the biological, behavioral, and environmental factors that affect breastfeeding continues to grow, researchers and lactation consultants will identify additional research areas. Thus, the cycle of describing and explaining phenomena, testing interventions to improve practice, and ultimately improving breastfeeding outcomes worldwide will continue.

Breast Feeding↗

PubMed2003

Seasonal evolution of faecal egg output by gastrointestinal worms in goats on communal farms in eastern Namibia.

As a more detailed continuation of a previous study, faecal samples for worm egg counts were collected per rectum from ten marked adult animals in selected flocks of goats, in each of six villages evenly spread out in the communal farming district of Okakarara in eastern Namibia. The study was conducted on a monthly basis from August 1999 to July 2000. Average faecal worm egg counts (FECs) were highest during the warm-wet season, much lower during the cold-dry months and moderate during the hot-dry season. Least square means of FECs were 2140, 430 and 653 per gram of faeces for the three seasons, respectively. Seasonal variation in egg counts was significant (P < 0.0001). Gastrointestinal strongyles, and to a lesser extent Strongyloides species, were the predominant parasite groups identified in goats. Kidding rates peaked in the cold-dry season and mortality rates in the hot-dry season. Results of this study suggest that gastrointestinal parasitism may be a problem that accentuates the effect of poor nutrition on small ruminants during the season of food shortages in the east of Namibia and that the use of FECs per se to assess the severity of gastrointestinal parasitic infection in goats followed by chemoprophylactic strategic and/or tactical treatment, may not be the best approach to addressing the worm problem under resource-poor conditions. The use of the FAMACHA system that identifies severely affected animals for treatment is technically a better option for communal farmers.

Animals↗

PubMedDate not supplied

How can we implement current therapies and interventions to achieve glycemic control?

OBJECTIVE: To discuss the appropriate use of oral therapies to achieve and sustain glycemic targets in patients with type 2 diabetes. METHODS: The stages in the development and progression of type 2 diabetes are reviewed, and the limitations of single-drug therapy are addressed. RESULTS: The development of diabetes is a staged progression; affected patients show evolution through numerous stages of glucose intolerance before clinical diabetes manifests. Beta cell function continues to deteriorate until absolute failure occurs; however, other factors, such as glucose and lipid toxicities, insulin resistance in peripheral tissues, and loss of the first-phase insulin response, further impair the body's ability to regulate release of insulin in response to glucose. Traditional treatment algorithms often fail to address the progressive, multifaceted nature of type 2 diabetes, with its numerous related abnormalities. Combination therapy with orally administered agents can be used to manage glucose concentrations and other risk factors safely and effectively. CONCLUSION: The therapeutic goal in type 2 diabetes is to achieve and maintain a physiologic profile as close to normal as possible. This outcome necessitates treatment of multiple defects with use of various combinations of orally administered agents. Clinicians should focus on effective treatment of these defects to achieve established targets.

Algorithms↗

PubMedDate not supplied

Performance appraisal in the age of TQM.

Performance evaluation is often used as a tool to determine salary adjustment as well as an opportunity to improve job performance. When inappropriately applied, performance evaluations may be perceived as being unfair, wasteful, and demeaning. In some organizations, there has been a trend to break down job functions to their most detailed level, weight each activity, judge it, and then add up all the invalid numbers to achieve a more invalid judgment of a person's performance. This non-Gestalt evaluation is an inspection philosophy that has not served manufacturing or health care very effectively. Over the past four years, we have evolved a performance evaluation process at Minneapolis Children's Medical Center for physicians in both patient care and management roles. In this article, we will describe the evolution to the present system and discuss its dovetailing with customer service-driven continuous quality improvement efforts and our plans to improve the process.

Employee Performance Appraisal↗

PubMed1998

The evolution of a German teleradiology system.

This paper describes the evolution of a german teleradiology system. The development started from simple image file transfer, continued with a dedicated teleradiology system and ended up with a general radiology workstation with teleradiology features. The main features, advantages and drawbacks of the different generations are described. The own developments are compared with developments at other places. The influence by standards is also included in this investigation. The latest systems are mainly used by the radiologists and the image transfer for scientific cooperation is nowadays just one of several application fields of teleradiology.

Germany↗

PubMed1976

Closed head injury: a simplified approach.

In early evaluation of the head-injured patient one must continuously be alert for signs requiring operative intervention. If a neurologic deficit is in evolution, it should manifest itself by producing a change which will not be missed by careful frequent clinical evaluation.

Airway Obstruction↗

PubMed2001

[Pre-eclampsia and eclampsia. Experience at the Centro Médico Nacional de Torreón].

OBJECTIVE: To assess the epidemiological aspects of the patient with preeclampsia assisted in the Centro Medico Nacional Torreón, of the IMSS. MATERIAL AND METHOD: We carried out a retrospective and descriptive survey of 138 consecutive admissions to the Department of Gynecology and Obstetrics, between January first to December 31, 1997 with diagnosis of preeclampsia according to the criteria of the ACOG. Maternal and perinatal secondary complications of this pathology were determined. Mortality and lethality rates were also estimated. Descriptive statistics were used for the analysis. RESULTS: The prevalence rate of preeclampsia was 2.1%. The age of the patients was 23.2 years (SD 3.05) and the gestational age at the moment of the diagnosis of preeclampsia of 36.4 weeks (SD 3.2). Only 41.3% of the patients received regular prenatal control. The prevalence rate of maternal complications was 29.0%. Mortality rate was 0.15 x 1,000, lethality rate was 0.72%. The weight average of the new born were 2.011 kg (SD 0.429), the Apgar to the first minute 7.72 (SD 0.98) and 8.66 (SD 1.10) to the fifth minute. The prevalence rate of perinatal complications was 35.5%. There were 15 neonatal deaths (10.9%) and one fetal lost. CONCLUSIONS: The preeclampsia-eclampsia is still a disorder with a great influence in the maternal and perinatal morbidity and mortality rates. It is necessary to continue working for find out the way of preventing their appearance or modifying their evolution avoiding the eclampsia or other serious forms of this illness.

Adult↗