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Grandmother hypothesis and primate life histories.

The adaptive significance of midlife menopause in human females has long engaged the attention of evolutionary anthropologists. In spite of extensive debate, the problem has only recently been examined in the context of primate life histories. Here I extend those investigations by comparing life history traits in 16 primate species to test predictions generated from life history theory. In humans, late ages of maturity and higher than expected birth rates are systematically associated with extended postmenopausal longevity. Links among these adjustments on the primate pattern can explain how selection could slow somatic senescence without favoring extension of the fertile span. This conclusion is consistent with the observation that our fertile spans are similar to those of other pongids. The shape of the argument herein demonstrates the utility of life history theory for solving problems of adaptive evolution in female life history traits, with consequences for broader arguments regarding human evolution.

Aging↗

Mediastinal lymphadenopathy in congestive heart failure: a sequential CT evaluation with clinical and echocardiographic correlations.

The aim of this study was to evaluate the frequency and evolution after treatment of mediastinal lymphadenopathy associated with congestive left heart failure on CT scans in correlation with clinical and echocardiographic findings. Thirty-one consecutive patients with subacute left heart failure underwent a clinical evaluation using the NYHA classification, a CT examination, and transthoracic echocardiography at the time of initial presentation (T1). After initiation of medical treatment (T2), follow-up CT scans were systematically obtained together with a clinical evaluation. At T1, all patients showed severe (type III: n=12, 39%; type IV: n=12, 39%) to moderate (type I, n=1, 3%; type II, n=6, 19%) dyspnea with a mean ejection fraction of 39% (range 22-74%). On initial CT scans, enlarged mediastinal lymph nodes were seen in 13 patients (42%) with blurred contours in 5 patients (16%) and hazy mediastinal fat in 1 patient (3%). Significant decrease in the size of lymphadenopathy was observed between T1 and T2 (T1, n=13, 42% vs T2, n=10, 32%; p<0.05) with a concurrent decrease in the severity of dyspnea (grade III-IV dyspnea at T1, n=24, 78% vs grade I-II dyspnea at T2, n=26, 83.5%). Patients with enlarged lymph nodes at T1 showed: (a) a significantly lower ejection fraction at echocardiography than those without lymphadenopathy (mean+/-SD value: 34+/-12.9 vs 43+/-13.8%; p=0.04); (b) a significantly larger diameter of the right superior pulmonary vein (mean+/-SD value: 17+/-2.75 vs 14+/-3.9 mm; p=0.04); and (c) a higher frequency of abnormal peribronchovascular thickening ( n=5 vs n=1; p=0.06). Mediastinal lymphadenopathy associated with subacute left heart failure was observed in 13 patients (42%), showing regression after initiation of treatment in 8 of 13 patients (62%).

Aged↗

Is there a rate-limiting step in the catalytic cycle of Ni-Fe hydrogenases?

The question of the existence of a rate-limiting step in the catalytic cycle of Ni-Fe hydrogenases was taken up by using the sets of data available in the case of two specific enzymes: the hydrogenase from Thiocapsa roseopercisina, in which isotope effects have been systematically investigated over a wide pH range, and the enzyme from Desulfovibrio fructosovorans, for which the activities and the redox properties have been studied in two different forms, the wild type and the P238C mutant. When these data are analyzed in the light of appropriate kinetic models, it is concluded that electron transfer and proton transfer are rate limiting in the H2 uptake and H2 evolution reactions, respectively. This proposal is consistent with the data available from other Ni-Fe enzymes.

Catalysis↗

Comparative aspects of gait, scaling and mechanics in mammals.

In phylogenetically based systematics, Mammalia is the nomenclatural term which designates the clade stemming from the most recent common ancestry of monotremes and theria [, Sys. Biol. 43 (1994) 497]. Considering that locomotor performance is a prevalent function to provide the necessary conditions to survive and transmit genes, it may be questioned if the diverse types of locomotion exhibited by extant mammals could have played a role in their evolution, or have only followed it. We may look after the structural and behavioural features which are involved in mammal locomotion compared to other tetrapods and test if they fit with the proposed phylogeny. Several factors may be checked: scaling effect in relation to gravitational constraints; geometrical distribution of masses in the body, and relative mechanical role of the limbs in the production of the external forces necessary to forward motion. Classically, it was thought that the fastest gaits used by terrestrial mammals were based upon a unique kind of limb motion co-ordination, called asymmetrical gaits, which in turn may be thought to be related to a peculiar neuronal wiring. Kinematic analysis brings an insight to this topic. Is the search for an ancestral mammalian locomotor pattern judicious? Notice the small size of many of the first mammals and their probable locomotor plasticity. (relation between grain size of the elements within the substrate and the organism scale). At a small size, the gravitational constraint is less important, and the distinction between terrestrial and arboreal has probably no sense when the limbs are the principal motor elements. There remains the importance of the geometrical distribution of body elements, the proportions of the limbs and of the head-neck complex, the tail merely as an appendix, a set of factors which may have generated the frame of constraints within which diverse locomotor modes have evolved.

Animals↗

Relaxation of H2O from its /04>- vibrational state in collisions with H2O, Ar, H2, N2, and O2.

We report rate coefficients at 293 K for the collisional relaxation of H2O molecules from the highly excited /04>(+/-) vibrational states in collisions with H2O, Ar, H2, N2, and O2. In our experiments, the mid R:04(-) state is populated by direct absorption of radiation from a pulsed dye laser tuned to approximately 719 nm. Evolution of the population in the (/04>(+/-)) levels is observed using the combination of a frequency-quadrupled Nd:YAG laser, which selectively photolyses H2O(/04>(+/-)), and a frequency-doubled dye laser, which observes the OH(v=0) produced by photodissociation via laser-induced fluorescence. The delay between the pulse from the pump laser and those from the photolysis and probe lasers was systematically varied to generate kinetic decays. The rate coefficients for relaxation of H2O(/04>(+/-)) obtained from these experiments, in units of cm3 molecule(-1) s(-1), are: k(H2O)=(4.1+/-1.2) x 10(-10), k(Ar)=(4.9+/-1.1) x 10(-12), k(H2)=(6.8+/-1.1) x 10(-12), k(N2)=(7.7+/-1.5) x 10(-12), k(O2)=(6.7+/-1.4) x 10(-12). The implications of these results for our previous reports of rate constants for the removal of H2O molecules in selected vibrational states by collisions with H atoms (P. W. Barnes et al., Faraday Discuss. Chem. Soc. 113, 167 (1999) and P. W. Barnes et al., J. Chem. Phys. 115, 4586 (2001).) are fully discussed.

Journal Article↗

Drag reduction by polymer additives in decaying turbulence.

We present results from a systematic numerical study of decaying turbulence in a dilute polymer solution by using a shell-model version of the finitely extensible nonlinear elastic and Peterlin equations. Our study leads to an appealing definition of the drag reduction for the case of decaying turbulence. We exhibit several new results, such as the potential-energy spectrum of the polymer, hitherto unobserved features in the temporal evolution of the kinetic-energy spectrum, and characterize intermittency in such systems. We compare our results with the Gledzer-Ohkitani-Yamada shell model for fluid turbulence.

Journal Article↗

Evolution of spontaneous atherosclerotic plaque rupture with medical therapy: long-term follow-up with intravascular ultrasound.

BACKGROUND: Ruptured coronary atheromatous plaque is generally considered to involve a high risk of subsequent clinical events. Few data are available on the natural evolution of non-culprit-lesion ruptured plaque. We therefore used serial intravascular ultrasound (IVUS) to study how such lesions, detected in the context of a first acute coronary syndrome with elevated troponin I levels, develop. METHODS AND RESULTS: Fourteen patients with 28 distinct plaque ruptures (2+/-1 per patient) without significant associated stenosis (minimal lumen cross-sectional area >4 mm2) were included and systematically treated with 40 mg statin and antiplatelet agent (clopidogrel and aspirin for > or =9 months). Mean clinical and IVUS follow-up was 22+/-13 months (median, 22 months). No clinical event related to the lesion under study occurred. On final IVUS examination, half (14 of 28) of the ruptured plaques had healed, and the degree of stenosis tended to diminish (stenosis, 22+/-17% versus 29+/-17% at baseline; P=0.056). No healing-prediction criterion could be identified. CONCLUSIONS: Nearly 2 years of follow-up found that spontaneous coronary atheromatous plaque rupture without significant stenosis detected on first acute coronary syndrome healed without significant plaque modification in 50% of cases with medical therapy.

Aged↗

[Pseudo-tumoral cerebellar infarction. Diagnostic, therapeutic and prognostic aspects in 12 cases (author's transl)].

In those 12 observations, without associated lesion in the brain stem, diagnosis is done 3 times at autopsy, 8 times at surgical time, and once before it, on clinical and radiographic arguments. Diagnosis must be systematically evoked in front of vestibular symptoms, before severe signs, related to intracranial hypertension and brain stem compression, become evident. Iodoventriculography (7 times) and principally computerized tomography (2 times) bring conclusive arguments for diagnosis. Those infarcts are situated 9 times in the territory of the postero-inferior cerebellar artery and 3 times in the area supplied by the antero-superior cerebellar artery. Spontaneous evolution is always lethal, but prognosis after surgery is still severe (4 long term survivals in 9 cases) for the vascular system of those patients remains fragile.

Adult↗

[Psychiatric manifestations as the only clinical sign of hypothyroidism. Apropos of a case].

This article intends to demonstrate, by presenting a clinical case, the importance of the thyroid examination in psychiatric practice. After a brief presentation of the evolution of the conceptions regarding the relation between thyroid insufficiency and psychiatric pathology, a clinical case is reported. This 63 years old man was admitted in a psychiatric ward because of his persecutive delusions and behavioral disorders (agitation, agressivity). Cognitive (namely memory) impairment was also present at the time of admission. The endocrine investigation has documented, in spite of the absence of any suggestive physical signs, a thyroid insufficiency. After the replacement treatment, all symptoms but the cognitive dysfunction disappeared. The patient's evolution is presented clinically, also rated on MMSE and MADRS scales, and biologically (TSH and T4 determination) for a 4 months period. The absence of any pathognomonical psychiatric finding, the possibility of the absence of other signs and symptoms (namely physical) in the hypothyroid state, the presence of potentially irreversible cognitive deterioration, as well as the inocuity and sensibility of thyroid hormones examination justify the systematic thyroid evaluation for all new psychiatric patients.

Cognition Disorders↗

Further evidence for cosmological evolution of the fine structure constant.

We describe the results of a search for time variability of the fine structure constant alpha using absorption systems in the spectra of distant quasars. Three large optical data sets and two 21 cm and mm absorption systems provide four independent samples, spanning approximately 23% to 87% of the age of the universe. Each sample yields a smaller alpha in the past and the optical sample shows a 4 sigma deviation: Delta alpha/alpha = -0.72+/-0.18 x 10(-5) over the redshift range 0.5<z<3.5. We find no systematic effects which can explain our results. The only potentially significant systematic effects push Delta alpha/alpha towards positive values; i.e., our results would become more significant were we to correct for them.

Journal Article↗

[Historical evolution of Marianao municipality: setting in which the fight against tuberculosis developed].

A research on the fight against tuberculosis in Marianao municipality was made. In Cuba, this campaign since its beginning was in the hands of private entities with limited resources that were inscrupulously managed. The Marianao municipality, established in 1878, had municipal administrations that implemented negative policies for the people's interests and propitiated the spreading of tuberculosis due to the terrible working and living conditions of the population. Since the triumph of the Revolution, in 1959, it was established in Cuba a systematic fight against tuberculosis with the introduction of the National Control Program that acts in a decentralized way from the municipal level. In this municipality, the incidence of tuberculosis has historically been a health problem, although at present there is a trend towards the decrease of this disease and it occupies the 13th place among the 15 municipalites of the province of Havana City.

Cuba↗

Speciation in Chlamydia: genomewide phylogenetic analyses identified a reliable set of acquired genes.

Horizontal gene transfer (HGT), a process through which genomes acquire sequences from distantly related organisms, is believed to be a major source of genetic diversity in bacteria. A central question concerning the impact of HGT on bacterial genome evolution is the proportion of horizontally transferred sequences within genomes. This issue, however, remains unresolved because the various methods developed to detect potential HGT events identify different sets of genes. The present-day consensus is that phylogenetic analysis of individual genes is still the most objective and accurate approach for determining the occurrence and directionality of HGT. Here we present a genome-scale phylogenetic analysis of protein-encoding genes from five closely related Chlamydia, identifying a reliable set of sequences that have arisen via HGT since the divergence of the Chlamydia lineage. According to our knowledge, this is the first systematic phylogenetic inference-based attempt to establish a reliable set of acquired genes in a bacterial genome. Although Chlamydia are obligate intracellular parasites of higher eukaryotes, and thus suspected to be isolated from HGT more than the free-living species, our results show that their diversification has involved the introduction of foreign sequences into their genome. Furthermore, we also identified a complete set of genes that have undergone deletion, duplication, or rearrangement during this evolutionary period leading to the radiation of Chlamydia species. Our analysis may provide a deeper insight into how these medically important pathogens emerged and evolved from a common ancestor.

Base Composition↗

The expression profiles of neurotrophins and their receptors in rat and chicken tissues during development.

Neurotrophic factors are target-derived proteins that promote the survival and differentiation of the innervating neurons. Increasing evidence indicate the involvement of these factors and receptors during the formation and maturation of the neuromuscular junction. To gain further insight on the expression pattern of these factors and receptors in developing spinal cord and skeletal muscle during the critical stages of synapse formation, a systematic study was performed with chicken and rat tissues using Northern blot analysis. The expression of all the neurotrophins was detected in skeletal muscle early in development, coincidental with the appearance of their corresponding receptors in the spinal cord. Taken together, the similar regulatory patterns observed in both rat and chicken tissues suggest that the potential roles of neurotrophins at the neuromuscular synapse are conserved throughout evolution.

Animals↗

Phylogenetic history of LINE-1 among arvicolid rodents.

The extent of restriction fragment sharing among arvicolid rodents was examined following Southern blotting with a reverse transcriptase region probe from long interspersed nuclear element 1 (LINE-1 or L1). DNAs from 30 species belonging to nine genera were digested with 11 restriction endonucleases. Following hybridization discrete bands were scored with respect to their presence or absence and intensity, and both within- and between-species comparisons were conducted. Intraspecific analyses revealed low but detectable levels of variation. Interspecific comparisons revealed three groups of bands: those present in all 30 species (6 out of a total of 248 bands), those phylogenetically informative in two or more species (130 out of 248), and those unique to a single species (114 out of 248). A multistate data matrix consisting of species by codes representing the intensities of informative bands was analyzed by maximum parsimony. Further, distance values between species were converted to rates using estimated fossil divergence times. Both the parsimony and rate analyses revealed differences between species in the extent of band sharing and in the intensities of common bands, indicating that the amplification and movement of LINE elements has occurred in episodic bursts during the history of this group. Systematic interpretations of the evolutionary trees were concordant with those previously obtained using other data sets, suggesting that although the amplification of repetitive sequences may occur episodically in this taxonomic group, there do appear to be some constraints.

Animals↗

Proteins of circularly permuted sequence present within the same organism: the major serine proteinase inhibitor from Capsicum annuum seeds.

The major serine proteinase inhibitor from bell pepper (Capsicum annuum, paprika) seeds was isolated, characterized, and sequenced, and its disulfide bond topology was determined. PSI-1.2 is a 52-amino-acid-long, cysteine-rich polypeptide that inhibits both trypsin (K(i) = 4.6 x 10(-9) M) and chymotrypsin (K(i) = 1.1 x 10(-8) M) and is a circularly permuted member of the potato type II inhibitor family. Mature proteins of this family are produced from precursor proteins containing two to eight repeat units that are proteolytically cleaved within, rather than between, the repeats. In contrast, PSI-1.2 corresponds to a complete repeat that was predicted as the putative ancestral protein of the potato type II family. To our knowledge, this is the first case in which two proteins related to each other by circular permutation are shown to exist in the same organism and are expressed within the same organ. PSI-1.2 is not derived from any of the known precursors, and it contains a unique amphiphilic segment in one of its loops. A systematic comparison of the related precursor repeat-sequences reveals common evolutionary patterns that are in agreement with the ancestral gene-duplication hypothesis.

Amino Acid Sequence↗

[Pica: a descriptive study of patients in a speciality medical center].

According to the DSM IV, pica is a trouble of alimentary behavior, which is characterized by the ingestion of non-nutriment substances during at least on the month. The main objective of this study conducted at the Clermont-de-l'Oise Interdepartmental Medical Center is to evaluate pica's prevalence for hospitalized patients. Secondary objectives are to describe clinical characteristics, complications and outcome upon the different therapeutic approaches. The patients hospitalized in the Adult and/or Pediatric Department of Psychiatry, which fulfilled the 4 criteria of the DSM IV, were considered eligible for the study. In order to better evaluate the severity of behavioral troubles evoked by item D of DSM IV definition, we elaborated specific severity and preoccupation scales. The severity scale reflects the complications due to the ingestion of the non-nutriment substances, the encountered risks in the case of persistence of these troubles as well as the patient's management. The preoccupation scale reflects the medical team's involvement towards the patient in order to prevent life-threatening complications. The two scales are graded from 0 to 5 according to the severity or to the degree of preoccupation, respectively. Only patients with scores 3 were considered as fulfilling the severity criteria. Among the 943 hospitalized patients at a selected time period, 23 adult patients have been considered eligible. According to these data, prevalence of pica was estimated at 2.44%. This value may seem an underestimation when compared to the values reported in the medical literature, which range from 9 to 25%. Additionally, among the 108 hospitalized infant patients, none fulfilled DSM IV criteria, which is surprising, as pica is relatively common in childhood. These results may be explained by the use of the more restrictive criteria of the DSM IV and also by the difficulties encountered in considering pica as an independent medical condition. Indeed, pica is often a secondary diagnosis associated with other psychiatric conditions characterized by profound mental deterioration. Two pathogenic factors were constantly searched in the medical records: iron-deficiency anemia and psychopathology. Cultural factors can be a priori eliminated, as most of these patients are in rupture with their family environment since low ages. Only two patients presented with iron-deficiency anemia and its correction did not result in pica's improvement. These findings do not support the -studies presenting pica as an iron-deficiency anemia induced trouble, which regress after a well-conducted iron replacement. Most patients were found to have precocious lack of affect in their medical history. All patients presented other associated psychiatric troubles including severe mental impairment (48%) and dysharmonic development (26%), as well as autistic troubles and schizophrenia. These data concur with other studies, which associate pica to other psychiatric disorders. Gluttony is a widely represented symptom in our study population (87%) and predisposes to food aspiration. It is the mark of frenetic orality and concerns comestible as well as non-comestible compounds. The ingestion of non-nutriment compounds could therefore be considered as an incapacity of discerning among different mouth-introduced substances. Auto- and hetero-aggressive disorders have been reported in 77% of the patients. These behaviors arise mostly in the phase of seeking of substances, especially if these are particularly attractive. The enhancement of the -anxiety, which often arises in the eventuality of hindering of the act, as well as the soothing effect of the ingestion, suggests a compulsive activity. This compulsive activity could be related to an addictive conduct. Pica could therefore be related to obsessive-compulsive disorders and benefit from its specific therapy, either behavioral or chemotherapy with serotonin-recapture inhibitors. The most common clinical forms of pica were phytophagia and geophagia, probably due to the facility of access to these substances. However, 31 distinct substances have been identified in our study. Pica's evolution often implies severe complications, which are sometimes life threatening in spite of a well-conducted treatment. Severity factors include the iteration of medical and surgical complications, as well as the type of ingested products. Our results show a high incidence of surgical complications, essentially gastro-intestinal. Due to the elevated incidence of complications and to the high rate of mortality, some authors proposed systematical search of pica for any gastro-intestinal troubles arising in patients suffering from mental disorders. For these patients for whom anamnesis is often difficult, a standard X-ray of the abdomen is an essential imaging study. Respiratory complications come in second position and infectious complications are seen mostly for the geo- and coprophagia-suffering patients, which contract intestinal parasitosis. Because of its multifactor causality, treatment of pica is complex, and results are often deceiving. Symptomatic neuroleptic therapy results in transient improvement and is indicated especially in delirious patients. Psychotherapy with behavioral approaches and different institutional approaches can be proposed. Indeed, pica could be considered as an acquired behavior, which could benefit from cognitive and behavioral therapies. Institutional management including supportive and compassionate care, restoration of self-confidence is interesting for these patients. Some authors even suggest that pica might be considered as a good indicator of the institution's care quality.

Adolescent↗

Evolution of serum amylase, lipase and immunoreactive trypsin during pancreatitis attacks.

The characteristics of the blood curves of alpha-amylase (SA), pancreatic lipase (SL) and immunoreactive trypsin (SIT) have been analyzed in a series of patients daily explored throughout the evolution of pancreatitis attacks; urines were also collected to estimate the amylase-creatinine clearance ratio (ACCR). The following results were obtained. a). The 3 enzymes profiles ran roughly parallel during an acute attack. b). SL rose far higher than SA at the onset of the attack but its decay displayed a shorter half-life than the latter; these features resulted in an absence of systematic difference between their times of return to normal levels at the end of the attack. c). SIT more closely correlated with SL than with SA. d). In common hospital practice, simultaneous SA and SL determinations were proving a more reliable help to diagnose pancreatitis attack than ACCR.

Acute Disease↗

Myelodysplastic syndromes: the pediatric point of view.

Myelodysplastic syndromes (MDS) are clonal disorders of the multipotent hematopoietic stem cell characterized by ineffective hematopoiesis and associated with marrow hypercellularity, increased intramedullary cell death and peripheral cytopenias of varying severity. Patients with myelodysplasia have a propensity (20% to 30% of cases) to undergo transformation into acute myeloid leukemia (AML), and a large body of evidence indicates that MDS represent steps in the multiphasic evolution of AML. Progression of the disease is characterized by expansion of the abnormal clone and inhibition of normal hematopoiesis leading to deterioration of the blood cell count and/or development of AML. MDS are relatively unusual in childhood, representing only 3% of pediatric hematological malignancies, although it has been reported that up to 17% of pediatric AML cases may have a previous myelodysplastic phase. The first systematic attempt at morphological classification of MDS was provided by the French-American-British (FAB) group. However, the FAB classification of MDS is only partially applicable in children. Some variants are extremely rare or absent (refractory anemia with ring sideroblasts and chronic myelomonocytic leukemia), and other peculiar pediatric disorders, represented by juvenile chronic myelogenous leukemia (JCML) and the monosomy 7 syndrome, are not included. Moreover, since there is a partial overlap between pediatric MDS and myeloproliferative disorders and the variants occurring in young children have rather specific features, some confusion still surrounds the nosographical definition of childhood MDS, so that none of the proposed classifications are widely accepted and used. Characteristically, some genetic conditions such as Fanconi's anemia, Shwachman's and Down's syndromes predispose to the development of MDS in childhood. The most common variants of childhood MDS are represented by JCML and the monosomy 7 syndrome, both disorders typically occurring in young children. JCML is characterized by a spontaneous growth of granulocyte-macrophage progenitors that show a striking hypersensitivity to granulocyte-macrophage colony-stimulating factor. Clinical presentation resembles that of some myeloproliferative disorders, with massive organomegaly usually not observed in the classically reported variants of MDS. Clinical features of the monosomy 7 syndrome resemble those observed in JCML and a differential diagnosis between these two entities relies upon the higher percentage of fetal hemoglobin, the more pronounced decrease in platelet count and, in some cases, the lack of the peculiar cytogenetic abnormality in the latter. With the number of children being cured of cancer constantly rising, a significant increase in secondary or chemotherapy-related myelodysplasia is being observed, and these disorders represent a formidable challenge for pediatric hematologists due to their poor response to chemotherapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Child↗