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PubMedDate not supplied

[Evolution of acute leukemia in myelodysplastic syndromes: prognostic histopathological factors in a series of bone marrow biopsies].

Out of 9,324 bone marrow biopsies, 250 cases of myelodysplastic syndromes (MDS) and 514 of acute non-lymphoid leukemia (AL) were collected. Twenty AL represented an evolution of MDS: the marrow had a mean cellularity of 58.5%, a mean percentage of blasts of 19% (55% of the cases had more than 10% of blasts in the marrow); only in one case (5%) benign lymphoid nodules (LN) were present. In 42 cases of MDS deceased without an evolution to overt AL, the bone marrow showed a cellularity of 60%, a mean percentage of blasts of 14% (only 29% had more than 10% of blasts); in 13 cases (31%) LN were present. Our data indicate that the percentage of bone marrow blasts is the most significant criterion for predicting an evolution to AL, although in the single case such evolution is not foreseeable. The presence of LN mostly in MDS without a leukemic progression could indicate a protective effect of NL, perhaps by means of an immunologic mechanism.

Acute Disease↗

PubMedDate not supplied

[Correlation between E.N.G. changes and the evolution of the hematic constants in patients under prolonged hemodialysis and renal transplantation].

An evolutive study of the E.N.G. on 25 patients affected of chronic renal failure (c.r.f.) in their previous periods and during the dialysis programme was developed. At the same time a large study on various serum changes was carried on. It is observed that the motor conduction velocity (M.C.V.) shows a decreasing evolution during dialysis, which mathematical patters is a branch of an equilateral hyperbola, of equation: (see article) The Na and K evolutive curves are also significatively fitted to the same mathematical pattern. It is observed a direct and inverse lineal correlation between M.C.V. values and those ones of the Na and K respectively, with p less than 0,05 and p less than 0,01. It is not observed any correlation of significatively value with the other serum parameters studied (R.A., Cl, Urea, Total proteins, Hematocrit, Ca, P, Creatinine, fluids and acid-base equilibrium). After a renal transplantation the M.C.V. presents a growing trayectory of the same mathematical pattern described before, reaching normal values about a year post-transplantion. The levels of Sodium serum follow a parallel trayectory than that one of the M.C.V. The recovery of the remainders serum parameters after renal transplantion occour during the first week, except for the hematocrit. It only remains a parallelism between the evolutive changes of M.C.V./Natremia during dialysis stage and after renal transplantion. These results seem to show a close dependence between variation of M.C.V. and Natremia. The hipoxia role over the sodium pump and the consequent variations of Natremia are discussed.

Blood Chemical Analysis↗

PubMedDate not supplied

Stochastic model of the evolution of viral hepatitis morbidity.

Starting from the elementary epidemiological processes, the authors develop an evolution equation of the function generating the probability distribution of the number of viral hepatitis (VH) patients and susceptible subjects. Evolution equations for moments of order 1 and 2 - resulting from the equation of the generating function-are also discussed on the ground of certain simplifying hypotheses. The formulae are applied to the analysis of VH morbidity evolution in several children communities. The data on the evolution of the different moments and of the probability distributions are used from the specification of epidemiological transmissibility and susceptibility parameters.

Epidemiologic Methods↗

PubMedDate not supplied

[The late follow-up evolution of myocardial infarct].

The aim of this paper was to study the long term evolution of patients (one to five years) after an acute myocardial infarction. Three hundred and twenty questionnaires were sent to patients admitted and diagnosed as acute myocardial infarction in the private sector of the Instituto Nacional de Cardiología "Ignacio Chávez". One hundred seventy five useful answers were obtained. Of these patients, coronariography was performed in 132 during the acute episode. In 57 CABG was performed. Most of them had three vessels or main left coronary artery occlusions. In the late long term evolution 68 patients had angor pectoris, 16 had unstable angina, more advanced lesions were found in 14 of them in a new angiographic study. In nine CABG was performed, three were treated with angioplasty, in two there was no indication for intervention. One had a new myocardial infarction and one died. Only four patients had a new myocardial infarction, two of them died, and another one had heart failure. In three of them a new angiographic study showed significant occlusion of the main left coronary artery. Eight patients died between the second and fourth year of evolution, in two it was a sudden death, two had a new myocardial infarction, three had heart failure and in one the cause of death was a stroke. Ten patients died during the first year of evolution the main cause was sudden death.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Oral lichen planus. An evolutive clinical and histological study of 45 patients followed up on for five years.

A study is made of 45 patients clinically and histologically diagnosed of oral lichen planus, and followed up on for 5 years. The course of the disease was monitored after three months and one, two and five years. The patients were classified in terms of lesion evolution (healed, improved, stationary or worse). Two evolutive groups were established for statistical purposes: (a) favorable (healed or improved lesions) and unfavorable cases (stationary or worsened oral lesions); and (b) healed and non-healed cases. Statistical correlations were established between these evolutive groups and different clinical and histological parameters, in an attempt to identify parameters of predictive value in the course of the disease. No statistically significant results were obtained, with the exception of inflammatory infiltrate. Thus, the depth of this infiltrate was found to be greater in patients with an unfavorable evolution (p = 0.02) than in those with a favorable course. Likewise, the inflammatory infiltrate was greater in non-healed than in healed cases.

Adrenal Cortex Hormones↗

PubMed1994

Genomic instability of microsatellite repeats and its association with the evolution of chronic myelogenous leukemia.

Tumorigenesis has been shown to proceed through a series of genetic alterations involving protooncogenes and tumor-suppressor genes. Investigation of genomic instability of microsatellites has indicated a new mechanism for human carcinogenesis in hereditary nonpolyposis colorectal cancer and sporadic cancer and this instability has been shown to be related to inherited predisposition to cancer. This study was conducted to determine whether such microsatellite instability is associated with the evolution of chronic myelogenous leukemia (CML) to the blast crisis. Nineteen CML patients clinically progressing from the chronic phase to accelerated phase or blast crisis and 20 other patients in the CML chronic phase were studied. By polymerase chain reaction assay, DNAs for genomic instability in five separate microsatellites in chromosome arms 5q (Mfd27), 17p (Mfd41), 18q (DCC), 3p (CI3-9), and 8p (LPL) were examined. Differences in unrelated microsatellites of chronic and blastic phase DNAs in 14 of 19 patients (73.7%) were demonstrated. Somatic instability in five microsatellites, Mfd27, Mfd41, DCC, CI3-9, and LPL, was detected in 2 of 19 (10.5%), 8 of 19 (42.1%), 11 of 19 (57.9%), 4 of 17 (23.5%), and 4 of 17 (23.5%) cases. In 10 of 19 cases (52.6%), genetic instability in at least two of five microsatellites was observed and was categorized as replication error (RER+) phenotype. CML evolution cases with myeloid, lymphoid, and mixed phenotypes and the blast crisis and accelerated phase showed somatic instability in a number of microsatellites. No alterations in leukemic cells at the chronic phase could be detected in any microsatellites. These data indicate instability of microsatellites (RER+) but not familial predisposition to possibly be a late genetic event in the evolution of CML to blast crisis. In the microsatellite of the DCC gene, complicated alterations in band patterns caused by instability as well as loss of heterozygosity (LOH) were observed in 13 of 19 cases (68.4%): instability in 9 cases, instability plus LOH in 2 cases, and only LOH in 2 cases. These highly frequent alterations in microsatellites, including instability and LOH, suggesting that secondary events due possibly to loss of fidelity in replication and repair machinery may be significantly associated with CML evolution.

Adult↗

PubMedDate not supplied

The correlation of clinical and laboratory parameters of the acute phase with the evolution of poststreptococcal glomerulonephritis in adults.

Prospective clinical study included the group of 44 patients who had the acute phase of poststreptococcal glomerulonephritis (PSGN) between the age of 18 and 22 during their military service. After the acute phase the patients were followed up to 5 years in order to investigate the influence of some clinical and laboratory parameters in the acute phase of PSGN on the evolution of this disease. The evolution of the disease, estimated on the basis of pathological findings in urine (proteinuria and erhytrocyturia), was found in 61% of patients. It was shown that severity of the clinical picture and the degree of proteinuria in the acute phase of PSGN were in direct correlation with the evolution of disease. On the other hand, the elevated concentrations of circulatory immune complexes (CIC) and cryoglobulin in the acute phase did not significantly affect the evolution of the disease although in some degree it contributed to the severity of pathological findings in the urine.

Acute Disease↗

PubMedDate not supplied

[Evolution of fecundity in the Valencian community during the 1975-1990 period].

BACKGROUND: To study the evolution of specific cases of fertility by age groups in the Autonomous Region of Valencia, between 1975 and 1990, and compare this development with the evolution on a national level. METHODS: The specific fertility rates were calculated for seven 5-year age groups within the female fertility period (15-49 years). The number of births per age of mother (Natural Movement of the Spanish Population) has been used and the denominator is the female population calculated be geometrical interpolation from the figures provided by different censuses and electoral roles for each one of the age groups. The study period is 1975 to 1990. RESULTS: The evolution of the fertility rate in the Autonomous Region of Valencia is declining in all age groups except the 30-34 year age group, where fertility showed a slight increase at the end of the eighties, the same as in the rest of the country. Worthy of mentioned is the 15-19 year old group, with figures below the national level, and the 25-29 year old group, where the figures are greater than for the rest of the country as a whole. On a province (county) level, the development is similar to what has been described above. Alicante has the highest figure out of the three provinces (counties) for women in the 15-19 and 35-39 year age ranges. CONCLUSION: The evolution of the fertility rate in the Autonomous Community of Valencia is similar to the development in the rest of the country, a slight increase being detected in women in the 30 to 40 year group, which is similar to what has happened in other European countries.

Adolescent↗

PubMed1997

Evolutive study of the functional results after restorative proctocolectomy for ulcerative colitis.

AIM: Evolutive study of the functional results after restorative proctocolectomy for ulcerative colitis. PATIENTS AND METHODS: Prospective study in 24 patients with an ileoanal "J" pouch (n = 8: mucosectomy and hand-sewn anastomosis; n = 16: stapled anastomosis without mucosectomy). A clinical survey was carried out during two evolutive follow-ups of the functional pouch (medians: 14.5 and 39.0 months) as well as an anorectal manometry study during the preoperative period and in two follow-ups after the creation of the pouch (medians: 6.0 and 35.5 months). RESULTS: The mean frequency of defecation per 24 hours and per night was significantly reduced in the first follow-up (5.5 [24 h]; p < 0.003 and 1.0 [per night]; p < 0.009) compared with the postoperative period (7.9 [24 h] and 1.4 [per night]), with no significant changes in the second follow-up (5.5 [24 h] and 0.9 [per night]). At the same time, it has been significantly lower in patients with stapled anastomosis in the different evolutive follow-ups. One patient (4.2%) had major fecal incontinence in the two evolutive follow-ups and 7 (29.2%) and 6 (25%) patients had minor incontinence in the first and second follow-up respectively. The mean maximum resting anal pressure in the first follow-up was significantly lower (p = 0.002) in patients with mucosectomy than the values observed in patients with stapled anastomosis (35.4 vs 68.0 mmHg). In the second follow-up increased significantly (p = 0.046) only in patients with mucosectomy (55.1 mmHg). Recto-anal inhibitory reflex was present in 2 (10%) and 9 (45%) patients in the first and second follow-up respectively. CONCLUSIONS: The functional results improve significantly with the follow-up time, fundamentally during the first year of the functional pouch.

Adult↗

PubMed1998

Clinical features and evolution of antinuclear antibody positive individuals in a rheumatology outpatient clinic.

OBJECTIVE: To identify individuals with antinuclear antibodies (ANA) not fulfilling criteria for systemic lupus erythematosus (SLE) or other connective tissue diseases (CTD); to describe their clinical and serological features, to identify factors indicating evolution to SLE. METHODS: A case-control study, based on retrospective evaluation of clinical files. The cases were ANA positive individuals (n = 50) examined in a medical outpatient setting, for symptoms compatible with SLE, but not fulfilling SLE classification criteria. Two patients with SLE were matched to each case in terms of age at initial symptom onset and sex. Thyroid autoimmunity was assessed by detecting antithyroid antibodies. Fisher's exact test and conditional logistic regression were used to evaluate the predictive ability of initial findings for SLE development. RESULTS: ANA positive individuals suspected of having a CTD present a wide variety of symptoms and findings, usually at the 4th to 5th decade of life. Antibodies to Sm and U1RNP were absent; anti-Ro(SSA) and anti-La(SSB) occurred in 6%, while anti-dsDNA occurred in less than 10% of the cases. Arthritis, butterfly and discoid rash, Raynaud's phenomenon, and anti-Ro/SSA antibodies are the initial findings indicating evolution to SLE. Hematological abnormalities such as leukopenia and thrombocytopenia as well as constitutional symptoms such as easy fatigue and arthralgias are not associated with evolution to SLE. Antithyroid antibodies were detected in 16% of the cases and 2.3% of controls. CONCLUSION: ANA may connote a form of systemic autoimmunity that is expressed as a wide variety of complaints, even in the absence of a definite diagnosis of CTD. Arthritis, rash, Raynaud's phenomenon, and anti-Ro/SSA antibodies indicate evolution to SLE. Autoimmune thyroid disease occurs in ANA positive individuals not fulfilling SLE classification criteria rather than in patients with SLE.

Adult↗

PubMed2005

Fold recognition by combining sequence profiles derived from evolution and from depth-dependent structural alignment of fragments.

Recognizing structural similarity without significant sequence identity has proved to be a challenging task. Sequence-based and structure-based methods as well as their combinations have been developed. Here, we propose a fold-recognition method that incorporates structural information without the need of sequence-to-structure threading. This is accomplished by generating sequence profiles from protein structural fragments. The structure-derived sequence profiles allow a simple integration with evolution-derived sequence profiles and secondary-structural information for an optimized alignment by efficient dynamic programming. The resulting method (called SP(3)) is found to make a statistically significant improvement in both sensitivity of fold recognition and accuracy of alignment over the method based on evolution-derived sequence profiles alone (SP) and the method based on evolution-derived sequence profile and secondary structure profile (SP(2)). SP(3) was tested in SALIGN benchmark for alignment accuracy and Lindahl, PROSPECTOR 3.0, and LiveBench 8.0 benchmarks for remote-homology detection and model accuracy. SP(3) is found to be the most sensitive and accurate single-method server in all benchmarks tested where other methods are available for comparison (although its results are statistically indistinguishable from the next best in some cases and the comparison is subjected to the limitation of time-dependent sequence and/or structural library used by different methods.). In LiveBench 8.0, its accuracy rivals some of the consensus methods such as ShotGun-INBGU, Pmodeller3, Pcons4, and ROBETTA. SP(3) fold-recognition server is available on http://theory.med.buffalo.edu.

Algorithms↗

PubMed2002

The evolution of the ribonucleotide reductases: much ado about oxygen.

Ribonucleotide reduction is the only known biological means for de novo production of deoxyribonucleotides, the building blocks of DNA. These are produced from ribonucleotides, the building blocks of RNA, and the direction of this reaction has been taken to support the idea that, in evolution, RNA preceded DNA as genetic material. However, an understanding of the evolutionary relationships among the three modern-day classes of ribonucleotide reductase and how the first reductase arose early in evolution is still far off. We propose that the diversification of this class of enzymes is inherently tied to microbial colonization of aerobic and anaerobic niches. The work is of broader interest, as it also sheds light on the process of adaptation to oxygenic environments consequent to the evolution of atmospheric oxygen.

Allosteric Regulation↗

PubMed2005

Protein evolution in the context of Drosophila development.

The tempo at which a protein evolves depends not only on the rate at which mutations arise but also on the selective effects that those mutations have at the organismal level. It is intuitive that proteins functioning during different stages of development may be predisposed to having mutations of different selective effects. For example, it has been hypothesized that changes to proteins expressed during early development should have larger phenotypic consequences because later stages depend on them. Conversely, changes to proteins expressed much later in development should have smaller consequences at the organismal level. Here we assess whether proteins expressed at different times during Drosophila development vary systematically in their rates of evolution. We find that proteins expressed early in development and particularly during mid-late embryonic development evolve unusually slowly. In addition, proteins expressed in adult males show an elevated evolutionary rate. These two trends are independent of each other and cannot be explained by peculiar rates of mutation or levels of codon bias. Moreover, the observed patterns appear to hold across several functional classes of genes, although the exact developmental time of the slowest protein evolution differs among each class. We discuss our results in connection with data on the evolution of development.

Algorithms↗

PubMed2026

Satellite DNA evolution in Tytonidae (Aves: Strigiformes): dynamic repeat landscapes despite conserved karyotypes.

The elevated chromosome numbers observed in Tytonidae relative to the putative ancestral avian karyotype suggest that lineage-specific chromosomal fissions may have played an important role in the evolutionary history of this family. Here, we provide the first cytogenetic characterization of the American barn owl (Tyto furcata) and performs a comparative repeatome analysis across members of the Tytonidae, including other two species, the Western barn owl (Tyto alba), and the Oriental bay owl (Phodilus badius). The karyotype of T. furcata showed a 2n = 92, closely resembling that previously described for T. alba, indicating a high degree of chromosomal conservation within Tytonidae. Although T. furcata and T. alba exhibit similar karyotypic organization, comparative repeatomic analyses revealed differences in their composition, including variation in satellite DNA (satDNA) repertoires and abundance. Eight satDNA families were identified in T. furcata, nine in T. alba, and 28 in P. badius, highlighting the dynamic evolution of repetitive sequences. Several satDNA families were shared between T. furcata and T. alba, whereas some appeared species-specific, supporting the library hypothesis of satDNA evolution. In P. badius, multiple satDNAs exhibited similarity to transposable elements, suggesting that mobile elements contributed to their diversification. Cytogenetic analyses demonstrated centromeric heterochromatin distribution in T. furcata, as well as a large heterochromatic W chromosome enriched in DNA repeats. The localization of satDNAs in centromeric regions and the apparent accumulation of repeats on the W chromosome reinforce the role of repetitive sequences in chromosome organization and sex chromosome differentiation. Together, these findings reveal repeatome diversification despite conserved macrochromosomal structure and provide new insights into genome evolution and chromosomal dynamics in birds.

Animals↗

PubMed1983

Exponential evolution: implications for intelligent extraterrestrial life.

Some measures of biologic complexity, including maximal levels of brain development, are exponential functions of time through intervals of 10(6) to 10(9) yrs. Biological interactions apparently stimulate evolution but physical conditions determine the time required to achieve a given level of complexity. Trends in brain evolution suggest that other organisms could attain human levels within approximately 10(7) yrs. The number (N) and longevity (L) terms in appropriate modifications of the Drake Equation, together with trends in the evolution of biological complexity on Earth, could provide rough estimates of the prevalence of life forms at specified levels of complexity within the Galaxy. If life occurs throughout the cosmos, exponential evolutionary processes imply that higher intelligence will soon (10(9) yrs) become more prevalent than it now is. Changes in the physical universe become less rapid as time increases from the Big Bang. Changes in biological complexity may be most rapid at such later times. This lends a unique and symmetrical importance to early and late universal times.

Animals↗

PubMed2005

Directed evolution: selecting today's biocatalysts.

Directed evolution has become a full-grown tool in molecular biology nowadays. The methods that are involved in creating a mutant library are extensive and can be divided into several categories according to their basic ideas. Furthermore, both screening and selection can be used to target the enzyme towards the desired direction. Nowadays, this technique is broadly used in two major applications: (industrial) biocatalysis and research. In the first field enzymes are engineered in order to produce suitable biocatalysts with high catalytic activity and stability in an industrial environment. In the latter area methods are established to quickly engineer new enzymes for every possible catalytic step, thereby creating a universal biotechnological toolbox. Furthermore, directed evolution can be used to try to understand the natural evolutionary processes. This review deals with new mutagenesis and recombination strategies published recently. A full overview of new methods for creating more specialised mutant libraries is given. The importance of selection in directed evolution strategies is being exemplified by some current successes including the beta-lactam acylases.

Amidohydrolases↗

PubMed2006

Monte Carlo simulation of early molecular evolution in the RNA World.

The origin of life remains a highly speculative field, mainly due to the shortage of our knowledge on prebiotic chemistry and basic understanding on the essence of life. In this context, computer simulation is expected to play an important role. For instance, the scenario concerning the genesis of the widely accepted RNA World remains blurry, though we have gathered some circumstantial evidence and fragmented knowledge on several supposed stages, including formation of polynucleotides from a prebiotic nucleotide pool, emergence of RNA replicases (RNA molecules catalyzing their own replication), and evolution of RNA replicases. It is highly valuable to simulate the stages as a continuous process to evaluate the plausibility of the supposition and study the rules involved. Here we construct a computer simulation on the process using Monte Carlo method. It demonstrates that primordial RNA replicases may appear and spread in a nucleotide pool provided they could recognize their own sequence and their complements as catalytic targets, and then may evolve to more efficient RNA replicases. Apart from its indication on the genesis of the RNA World, the vivid simulation of emergence of the "first replicative molecules" and their subsequent evolution is impressive and may help to get insight into "how could self-replication and Darwinian evolution, two key features of life, emerge in a non-life background?" thus improve our understanding of "what is life" when studying origins of life.

Biological Evolution↗

PubMed2005

Are genes of human intelligence related to the metabolism of thyroid and steroids hormones? - endocrine changes may explain human evolution and higher intelligence.

We propose the hypothesis that genes of human intelligence are related with metabolism of thyroid and steroids hormones, which have a crucial role in brain development and function. First, there is evidence to support the idea that during hominid evolution small genetic differences were related with significant endocrine changes in thyroid and steroids hormones. Second, these neuroactive hormones are also related with unique features of human evolution such as body and brain size increase, penis and breast enlargement, pelvic sexual dimorphism, active sexuality, relative lack of hair and higher longevity. Besides underling many of the differences between humans and great apes, steroids hormones promote brain growth and development, are important in the myelination process, explain sexual dimorphisms in brain and intelligence and improve specific cognitive abilities in humans. Supporting our hypothesis, recent studies indicate differences in neuroactive hormones metabolism between humans and non-human primates. Furthermore, a link between X chromosome genes and sex steroids may explain why the frequency of genes affecting intelligence is so high on the X chromosome. This association suggests that, during hominid evolution, there was a positive feedback in both sexes on the same genes responsible for secondary sexual character development and intelligence. This interaction leads to acceleration of development of human brain and intelligence. Finally, we propose that neuroactive hormone therapy may provide significant improvement in some cognitive deficits in all stages of human life and in cases of neurodegenerative diseases. However, further investigation is needed, mainly in the enzymatic machinery, in order to understand the direct role of these hormones in intelligence.

Animals↗