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1.
The relationship between phylogenetic reconstruction and evolutionary theory is reassessed. It is argued here that phylogenies, and evolutionary principles, should be analysed initially as independently from each other as possible. Only then can they be used to test one another. If the phylogenies and evolutionary principles are totally consistent with one another, this consilience of independent lines of evidence increases confidence in both. If, however, there is a conflict, then one should assess the relative support for each hypothesis, and tentatively accept the more strongly supported one. We review examples where the phylogenetic hypothesis is preferred over the evolutionary principle, and vice versa, and instances where the conflict cannot be readily resolved. Because the analyses of pattern and process must initially be kept separate, the temporal order in which they are performed is unimportant. Therefore, the widespread methodology of always proceeding from cladogram to evolutionary 'scenario' cannot be justified philosophically. Such an approach means that cladograms cannot be properly tested against evolutionary principles, and that evolutionary 'scenarios' have no independent standing. Instead, we propose the 'consilience' approach where phylogenetic and evolutionary hypotheses are formulated independently from each other and then examined for agreement.  相似文献   

2.
To examine the relationship between recall and recognition memory in amnesia, the authors conducted 2 experiments in which recognition memory was equated between patients with amnesia and control participants. It was then determined whether recall was also similar across groups. In Experiment 1, recognition was equated by providing amnesic patients with additional study exposures; in Experiment 2, recognition was equated by testing controls following a longer delay. These different methods of equating recognition across groups led to divergent results because amnesic patients' recall performance was lower than controls' recall performance in Experiment 1 but not in Experiment 2. These findings are accounted for by considering the differential contribution of recollection and familiarity to the performance of amnesic patients and controls in the 2 experiments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

3.
Testicular and ovarian fragments of Carassius auratus, taken during the reproductively active prespawning phase (June) of its annual reproductive cycle, were incubated with different concentrations (0 mg/ml, 0 ppm; 0.001 mg/ml, 1 ppm; 0.01 mg/ml, 10 ppm; and 0.02 mg/ml, 20 ppm) of gamma-hexachlorocyclohexane (gamma-HCH) in the presence of either exogenous precursor [3H]-17-hydroxyprogesterone ([3H]17-P) or carp hypophyseal homogenate. The free (unconjugated) and conjugated metabolites (glucuronides and sulfates) of [3H]-17-P [androstenedione (AD), androstenetrione, 17-hydroxyprogesterone, testosterone (T), 11-deoxycortisol (S), 17, 20alpha-dihydroxy-4-pregnen-3-one (17,20alphaP), 17, 20beta-dihydroxy-4-pregnen-3-one (17,20betaP), 7alpha-pregnanetetrols (7alpha-P), and other polar metabolites] were separated by thin-layer chromatography and high-performance liquid chromatography. The endogenous production of unconjugated (free) steroids T, 17,20betaP, S, and 11-ketotestosterone (11-KT) in response to gamma-HCH were measured by radioimmunoassay. Among the in vitro metabolism of [3H]-17-P, in males, free steroids of AD, T, 17,20alphaP, S, and polar-free steroids were increased with the decreased yield of 11-KT. Percentage yield of testosterone glucuronide (TG) was increased with highly significant decreased yields of polar glucuronide steroids. The sulfate steroids of 17, 20alphaP, 17,20betaP, S, and 11-KT remain unchanged. In females, the decreased percentage of yield of AD and S and elevated T were noticed. The yield of TG was increased with decreased yield of 7alpha-P glucuronides. The percentage yield of AD sulfate and sulfate steroids of 17,20alphaP, 17,20betaP, and S were noted to be increased, but the yield for S sulfate was very high. Endogenous production of T was increased in both sexes in the presence of gamma-HCH, but 11-KT in male and S in female were depressed. 17, 20betaP was stimulated at some concentrations in both sexes but levels were very low. Results indicate that gamma-HCH in vitro perturbed the steroid biosynthesis during this phase thereby affecting reproductive physiology.  相似文献   

4.
Chlamydia pneumoniae (C.pn.) is claimed to be of importance for the development of bronchial asthma in previously healthy individuals. This is a new and speculative theory. Earlier studies have mainly focused on C.pn. and exacerbation of asthma. If this new theory were true, one would expect titres of C.pn.-specific IgG to be higher or more common in patients compared with controls. It would also seem probable that pathobiological mechanisms as found in connection with other microorganisms could be demonstrated, i.e. presence of C.pn.-specific IgE and the capability of C.pn. to induce or enhance histamine release from basophil leukocytes. We therefore examined C.pn.-specific IgE, IgG and IgM in sera from 22 adults with bronchial asthma and 25 healthy controls. IgE was verified by passive sensitization of basophils from umbilical cord blood. The prevalence of IgE was approx. 69% and IgG approx. 23% in both groups. IgG-titres were between 1:16 and 1:64 in both groups. No IgM was found. Further, C.pn. could neither induce nor enhance histamine release from basophil leukocytes of patients or controls. We conclude that patients with bronchial asthma and healthy controls do not differ in relation to 1) C.pn.-specific IgE in sera, 2) the capability of C.pn. to induce or enhance histamine release from basophil leukocytes, since no such effect was found, or 3) previous C.pn. infection judged by the presence of specific IgG antibodies. Our results cannot support the theory that C.pn. is a cause of adult-onset asthma.  相似文献   

5.
Examined differences on 9 psychological measures among groups of 25 critically ill hospitalized patients, 25 noncritically ill hospitalized patients, and 25 normal well controls. The instruments used were the Purpose in Life Test, the Fundamental Interpersonal Relations Orientation-Behavior test, and 2 listening measures on which eye-blink rates were recorded. 4 multivariate discriminate function analyses were performed to determine those variables that discriminated groups of Ss. The critically ill group expressed (a) more "purpose in life," (b) an increased need for affection and inclusion, (c) a decreased "wanted control" from others, and (d) an increased rate of eye blinks in response to disease-related material. The critically ill group appeared to be psychologically unique, since there was little difference between the results of the other 2 S groups. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

6.
The analysis of nuclear-encoded chitinase sequences from various angiosperms has allowed the categorization of the chitinases into discrete classes. Nucleotide sequences of their catalytic domains were compared in this study to investigate the evolutionary relationships between chitinase classes. The functionally distinct class III chitinases appear to be more closely related to fungal enzymes involved in morphogenesis than to other plant chitinases. The ordering of other plant chitinases into additional classes mainly relied on the presence of auxiliary domains-namely, a chitin-binding domain and a carboxy-terminal extension-flanking the main catalytic domain. The results of our phylogenetic analyses showed that classes I and IV form discrete and well-supported monophyletic groups derived from a common ancestral sequence that predates the divergence of dicots and monocots. In contrast, other sequences included in classes I* and II, lacking one or both types of auxiliary domains, were nested within class I sequences, indicating that they have a polyphyletic origin. According to phylogenetic analyses and the calculation of evolutionary rates, these chitinases probably arose from different class I lineages by relatively recent deletion events. The occurrence of such evolutionary trends in cultivated plants and their potential involvement in host-pathogen interactions are discussed.  相似文献   

7.
BACKGROUND: The periodontal attachment apparatus consists of the periodontal ligament, alveolar bone, cementum and supra-crestal connective tissue. They are interdependent and provide protection and support to the dentition. It is theorized that the integrity of the periodontal apparatus can be maintained throughout life by exercising comprehensive oral hygiene practices and routine dental care. Additionally, it appears to be unaffected by aging. As a consequence, the investigators performed a study to determine the effects of chronological aging on alveolar bone loss. OBJECTIVE: The present study was conducted to determine the relationship between oral alveolar bone loss, oral hygiene, and aging among African-American and Caucasian populations. METHODS: The population consisted of 229 individuals. There were 131 men and 98 women. With respect to race there were 89 African-Americans and 140 Caucasians. Oral examinations, oral hygiene and missing teeth determinations and bitewing radiographs were performed on all the individuals. Radiographs were digitized and measurements were made from the cementum/enamel junction to the alveolar bone crest. Measurements were made for both the maxillary and mandibular jaws. RESULTS: The results of the study showed a significant multiple linear regression model relationship between oral bone loss and aging. Oral hygiene was a factor, but contributed only slightly to the overall model. Race, gender and the number of missing teeth were not significant variables in the overall model. CONCLUSION: The results of this study suggest age-related alveolar bone loss.  相似文献   

8.
Mental health services have been routinely underutilized. This study investigated the influence of parents' gender, race, and psychopathology on perceived barriers and attitudes toward mental health utilization for themselves and for their children. A unique contribution of this study is the examination of father, mother, and child factors influencing service utilization from the parents' perspective. A total of 194 African American and Caucasian parents were recruited from the community to participate. Parents completed measures on barriers and attitudes toward treatment for themselves and for their children, history of mental health service utilization for themselves and for their children, and their own current psychological symptoms. Results indicated that 36.3% and 19.4% of parents and children, respectively, had used mental health services during their lifetime. Parents perceived fewer barriers and had more positive attitudes toward seeking services for their children than for themselves. Race and gender differences were found in parents' perceptions of barriers and attitudes toward treatment. Furthermore, barriers, attitudes, and psychopathology predicted parents' plans for future utilization of mental health services. The clinical implications of this study and directions for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

9.
10.
In a retrospective analysis of 87 cases of Caucasian childhood non-Hodgkin malignant lymphoma (NHML) from Lyon, France, all the case were diffuse lymphomas, but 47 were diagnosed as monomorphic small non-cleaved NHML, pathologically indistinguishable from Burkitt's lymphoma (BL). BL could then be the most frequent childhood lymphoma in France. This homogeneous series allows better definition of the characteristics of BL within NHML. Age distribution is similar to that of endemic BL, with a sex ratio of 3.7/1. Abdominal masses are initially present in 68% of the cases, whereas jaw is involved in only 4%. The disease is characterized by its overwhelming evolution in the absence of therapy. However, complete remission (CR) is usually obtained after the first chemtherapy regimen. Most relapses occur at 3-8 months. Death could be related to cerebrospinal fluid (CSF) involvement, local recurrence or secondary marrow involvement. Ninety per cent of the patients alive with no evidence of disease (NED) 8 months after CR can be considered as definitely cured. Our study on Caucasian children with NHML indicates that, from histological and clinical criteria, nearly half the cases are very similar to African BL. Even though EBV rarely associated with our cases, BL could be a worldwide lymphoma.  相似文献   

11.
Leptin is a recently isolated peptide hormone released from adipocytes that has been postulated to play a role in appetite regulation and energy metabolism. Aging affects both food intake and body composition. Body composition is also affected by ethnicity. We have evaluated the relationships between serum leptin levels, age, body composition (by dual-energy x-ray absorptiometry), and hormonal parameters in a cross-sectional study of 94 women, 53 African-American (AAF) and 41 Caucasian (CF). Our hypotheses were as follows: (1) changes in body composition would be related to age in a sinusoidal pattern, (2) changes in serum leptin would parallel changes in body fat, (3) serum leptin levels would be influenced by body fat distribution, and (4) serum leptin would be related to serum concentrations of sex hormones. Serum leptin paralleled changes in body fat and body mass index (BMI) with age. In the entire group, serum leptin correlated closely with measures of body fat, including BMI and total fat mass, and there was no difference in leptin levels between the two ethnic groups. In simple regression analysis, serum leptin was related to both serum estradiol and testosterone. The relationship between serum leptin and trunk fat was linear in both groups, but significantly different in AAF and CF (P = .014). Serum leptin was associated with the trunk to lower-extremity fat ratio in CF (r = .67, P = .001) but not in AAF. Body fat was increased with advancing age until about 65 years and then declined. Measures of lean body mass declined linearly with age in the entire group, as well as both subgroups. In the entire group, total lean body mass and lean body mass corrected for BMI (lean body mass/BMI) were inversely related to age. In subjects aged less than 60 years AAF were stronger (P < .05) and had both a larger BMI and fat mass (P < .05) than CF. However, the patterns of age-related changes in fat body mass, lean body mass, and BMI were similar in both groups. In the entire group, multiple regression analysis indicated that the age, free thyroxine index (FTI), and leptin concentration were predictors of the body composition and distribution of trunk to lower-body fat. These observations indicate that there is a sinusoidal relationship between body fat and age, with a decline in body fat in extreme old age in both AAF and CF, and that serum leptin concentrations are more closely related to body fat and BMI than to age or ethnicity.  相似文献   

12.
The three-dimensional structure of bacterial sphingomyelinase (SMase) was predicted using a protein fold recognition method; the search of a library of known structures showed that the SMase sequence is highly compatible with the mammalian DNase I structure, which suggested that SMase adopts a structure similar to that of DNase I. The amino acid sequence alignment based on the prediction revealed that, despite the lack of overall sequence similarity (less than 10% identity), those residues of DNase I that are involved in the hydrolysis of the phosphodiester bond, including two histidine residues (His 134 and His 252) of the active center, are conserved in SMase. In addition, a conserved pentapeptide sequence motif was found, which includes two catalytically critical residues, Asp 251 and His 252. A sequence database search showed that the motif is highly specific to mammalian DNase I and bacterial SMase. The functional roles of SMase residues identified by the sequence comparison were consistent with the results from mutant studies. Two Bacillus cereus SMase mutants (H134A and H252A) were constructed by site-directed mutagenesis. They completely abolished their catalytic activity. A model for the SMase-sphingomyelin complex structure was built to investigate how the SMase specifically recognizes its substrate. The model suggested that a set of residues conserved among bacterial SMases, including Trp 28 and Phe 55, might be important in the substrate recognition. The predicted structural similarity and the conservation of the functionally important residues strongly suggest a distant evolutionary relationship between bacterial SMase and mammalian DNase I. These two phosphodiesterases must have acquired the specificity for different substrates in the course of evolution.  相似文献   

13.
Endoscopy is not significantly better than fiberoscopy for the diagnosis of minute cancers of the digestive tract. However, labeling of these lesions with an agent that can be detected videoendoscopically, with subsequent computer processing of the electronic signals, should facilitate endoscopic diagnosis of microlesions. We developed an antibody labeled with an indocyanine green(ICG) derivative that has a specific fluorescence emission at 807 nm upon excitation at 768 nm. The physiochemical characteristics of this labeled antibody resemble those of ICG. The activity of the antibody is suitable for immunohistochemical staining, and the antibody fluoresces under infrared ray excitation. This antibody should prove useful for performing vital immunostaining for infrared endoscopy.  相似文献   

14.
Similar conserved structures appear in apparently unrelated protein families. Thus, the superfamily of insulin shows an evolutionary relationship with the alpha-conotoxins of marine fish-hunting snails as indicated by methods of protein comparison. In order to reach statistical significance, the A-chains of different insulins, insulin-like growth factors, relaxins, insulin related peptides from invertebrates were drawn for comparison. These data were correlated with sequences from randomly chosen proteins. The alpha-conotoxins show identity scores up to 37.5% and similarity up to 56.2% toward the members of the insulin-superfamily. These scores conform to values achieved by comparing the relaxin and the insulin/IGF-sequences. The data show clearly that the identity and similarity values obtained in the comparison with the insulins are significantly higher than the scores of randomly chosen protein primary structures. According to our calculated data, this hormone system regulating metabolism and growth in vertebrates and the mentioned toxin-receptor system share the same evolutionary ancestor. However, this statistical approach has to be substantiated on gene level.  相似文献   

15.
Objective: Previous work suggests that elevated trait anger-out exacerbates pain responses in part through endogenous opioid dysfunction. The authors examined whether this opioid dysfunction affects not only perceived pain intensity, but also emotional responses to being hurt. Design: 79 chronic low back pain (LBP) patients and 46 healthy controls received opioid blockade (8 mg naloxone i.v.) and placebo in randomized, counterbalanced order in separate sessions. During each session, participants sequentially experienced finger pressure pain and ischemic forearm pain tasks, with emotional state assessed at baseline and postpain. Main Outcome Measures: Blockade effects indexing opioid modulation of emotional reactivity were derived by subtracting placebo from blockade condition emotional reactivity. Results: Significant Participant Type × Anger-Out interactions on blockade effects indicated that in LBP participants but not in controls, greater anger-out was associated with deficient opioid modulation of anxiety, anger, and fear reactivity to noxious stimulation. Across participant types, greater anger-in was associated with impaired opioid modulation of anxiety and fear reactivity. Anger-in opioid effects were partially due to overlap with general negative affect. Conclusions: Opioid dysfunction associated with trait anger-out may affect not only perceived pain intensity, but also pain-related suffering in individuals with chronic pain conditions. Implications for understanding the health effects of anger management styles are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

16.
17.
Psychological dependence was induced in rats by a 1-year intermittent exposure to intoxicating doses of ethanol, and recorded by the rat's ability to later take the same dose of ethanol independent of the offered concentration. Citalopram (10 or 40 mg/kg/day) was given for 3 weeks with ethanol available only the first and the last day; 10 mg/kg had no effect. On the first treatment day 40 mg/kg decreased ethanol intake. On the last treatment day 40 mg/kg had no effect. The following week the ethanol intake was higher than before the treatment in the 40 mg/kg group. During the four posttreatment weeks the ethanol intake of the 40 mg/kg group dropped significantly. Citalopram was retested 18 weeks after the first treatment during 1 week, with continuous access to ethanol; 10 mg/kg had no effect and 40 mg/kg decreased ethanol intake at day 1, reaching a minimum in day 3. A tolerance to this effect was seen at the end of the week. Thus, in this model an acute dose of citalopram can decrease ethanol intake, but tolerance to this effect develops when citalopram is given both with and without access to ethanol.  相似文献   

18.
The genome of physalis mottle tymovirus (PhMV) is 6673 nucleotides long and is rich in cytosine residues (40.58%) like other tymoviruses. The organization of the genes is also similar to that of five other tymoviruses whose sequences are known. However, PhMV has the longest 3' noncoding region as well as the longest replicase (RP) ORF. The RP sequences are similar to those of other tymoviruses (48-60% identity) whereas the coat proteins (CP) and the overlapping proteins (OP) are conserved to a lesser extent (30-50% and 26-34% respectively). A tetra peptide "GILG" was found to be present in all the tymoviral OPs. The PhMV RP also possesses the methyl transferase, polymerase and the helicase motifs found in all the Sindbis-like super group of plant viruses. A phylogenetic analysis of the six tymoviral sequences revealed that they do not have a rigid hierarchical similarity relationship.  相似文献   

19.
The reconstructed evolutionary process   总被引:1,自引:0,他引:1  
Phylogenies reconstructed from contemporary taxa do not contain information about lineages that have gone extinct. We derive probability models for such phylogenies, allowing real data to be compared with specified null models of evolution, and lineage birth and death rates to be estimated.  相似文献   

20.
Examined the relationship between theoretical orientation and research attitudes and interests among 233 doctoral students in clinical psychology. Responses to a survey sent to 10 doctoral training programs indicated that behaviorally oriented students are more interested in conducting research and are more likely to endorse the basic tenets of science than those students expressing a preference for psychodynamic or humanistic orientations. Behavioral students were also younger and more likely to have majored in psychology as undergraduates, suggesting an earlier commitment to a career in psychology. The results are discussed in terms of their implications for the role of training programs in encouraging clinical psychology graduate students to become better consumers of scientific literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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