Sexual conflict and speciation

We review the significance of two forms of sexual conflict (different evolutionary interests of the two sexes) for genetic differentiation of populations and the evolution of reproductive isolation. Conflicting selection on the alleles at a single locus can occur in males and females if the sexes have different optima for a trait, and there are pleiotropic genetic correlations between the sexes for it. There will then be selection for sex limitation and hence sexual dimorphism. This sex limitation could break down in hybrids and reduce their fitness. Pleiotropic genetic correlations between the sexes could also affect the likelihood of mating in interpopulation encounters. Conflict can also occur between (sex-limited) loci that determine behaviour in males and those that determine behaviour in females. Reproductive isolation may occur by rapid coevolution of male trait and female mating preference. This would tend to generate assortative mating on secondary contact, hence promoting speciation. Sexual conflict resulting from sensory exploitation, polyspermy and the cost of mating could result in high levels of interpopulation mating. If females evolve resistance to make pre- and postmating manipulation, males from one population could be more successful with females from the other, because females would have evolved resistance to their own (but not to the allopatric) males. Between-locus sexual conflict could also occur as a result of conflict between males and females of different populations over the production of unfit hybrids. We develop models which show that females are in general selected to resist such matings and males to persist, and this could have a bearing on both the initial level of interpopulation matings and the likelihood that reinforcement will occur. In effect, selection on males usually acts to promote gene flow and to restrict premating isolation, whereas selection on females usually acts in the reverse direction. We review theoretical models relevant to resolution of this conflict. The winning role depends on a balance between the 'value of winning' and 'power' (relating to contest or armament costs): the winning role is likely to correlate with high value of winning and low costs. Sperm-ovum (or sperm-female tract) conflicts (and their plant parallels) are likely to obey the same principles. Males may typically have higher values of winning, but it is difficult to quantify 'power', and females may often be able to resist mating more cheaply than males can force it. We tentatively predict that sexual conflict will typically result in a higher rate of speciation in 'female-win' clades, that females will be responsible for premating isolation through reinforcement, and that 'female-win' populations will be less genetically diverse.     

Effect of radiographic positioning on interpretation of cubital joint congruity in dogs

OBJECTIVE: To ascertain effects of x-ray beam centering and limb position on apparent congruity of a normal cubital joint (elbow). ANIMALS: 6 skeletally mature male Treeing Walker Coonhounds without physical, radiographic, or gross evidence of elbow abnormalities. PROCEDURE: Relative movement among humerus, radius, and ulna and measured joint space width on mediolateral and craniocaudal radiographic views was compared, using various x-ray beam centering and limb positions. RESULTS: Highest agreement and greatest certainty on subjective determination of congruity was for the flexed 90 degrees mediolateral radiographic view with the x-ray beam centered on the elbow. Distortion artifact of the proximal ulnar measurements was significant when the x-ray beam was centered on the midpoint of the radius. On the mediolateral view, the humeroradial joint space became significantly wide when the elbow was flexed. On the craniocaudal view, maximal humeroradial joint space width was obtained when the x-ray beam bisected the angle of the joint or was angled +30 degrees toward the humerus. CONCLUSIONS: Artifact distortion of joint width affected objective and subjective assessment of elbow congruity when the limb was placed in extreme flexion or extension or when the x-ray beam was not centered over the area of interest. Optimal visualization of the humeroradial joint space on the craniocaudal view was achieved when the x-ray beam bisected the angle of the elbow or was slightly angled toward the humerus. CLINICAL RELEVANCE: Elbow congruity was best assessed on the flexed 90 degrees lateral radiographic view with the x-ray beam centered on the joint.     

The relational self revealed: Integrative conceptualization and implications for interpersonal life.

The authors offer a new, integrative conceptualization of the relational self based on a synthesis of recent approaches to the self and significant others. This conceptualization provides a sharper and fuller definition of the relational self than does any existing approach alone and a common framework to interpret findings from separate literatures. The authors then present 5 propositions and evidence to support the thesis that relational selves exert a pervasive influence on interpersonal life. Specifically, relational selves (a) shape a wide range of psychological processes and outcomes, (b) exert their influence automatically, (c) serve basic orientation and meaning functions, (d) provide continuity and context-specific variability in personality, and (e) carry implications for psychological well-being. Discussion focuses on remaining issues and implications for future research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Angiotensin II and insulin induce growth of ciliary artery smooth muscle: effects of AT1/AT2 antagonists

PURPOSE: Abnormal growth of smooth muscle cells (SMCs) in small arteries of the eye is associated with hypertension and diabetes, and the complications that they induce. Migration and proliferation of SMCs into the intima are primary mechanisms involved in neointima formation. In aortic SMCs, angiotensin II (AII)-induced proliferation is inhibited by angiotensin type 1 (AT1) receptor antagonist. However, in small artery SMCs, in particular in the circulation of the eye, the effects of AII on migration and proliferation are unknown. METHODS: The effects of AII (10(-6) to 10(-10) M) on migration and proliferation of growth-arrested SMCs of porcine ciliary arteries were studied in the presence and absence of insulin (5 x 10(-10) M) by assaying DNA synthesis (3H-thymidine incorporation), cell number, and movement of SMCs across the membrane of a modified Boyden chamber. RESULTS: In the absence of insulin, only high concentrations (10(-6) to 10(-8) M) of AII induced DNA synthesis and increased cell number (P < 0.05); however, in the presence of insulin (5 x 10(-10) M), AII induced DNA synthesis and cell number at low concentrations (10(-10) M) and in a concentration-dependent manner (P < 0.05). In contrast to proliferation, AII induced SMC migration in a concentration-dependent manner in the absence of insulin (P < 0.05). The AT1 antagonist CGP48933 (10(-8) to 10(-12) M), but not the AT2 antagonist CGP42112 (10(-8) to 10(-12) M), inhibited AII (10(-8) M)-induced proliferation and migration in a concentration-dependent manner (P < 0.05). CONCLUSIONS: Our results suggest that AII is a potent mitogen for SMCs of ophthalmic arteries, an effect that is enhanced in the presence of insulin, and that it may be an important contributor to structural vascular changes in the ophthalmic circulation in hypertension associated with non-insulin dependent diabetes. The inhibition of AII-induced growth by an AT1 antagonist suggests that these drugs may be important therapeutic tools to prevent structural vascular changes in the ophthalmic vasculature under these conditions.     

Substance abuse issues in cancer patients. Part 2: Evaluation and treatment

The relationship between the therapeutic use of potentially abusable drugs for symptom control and the multifaceted nature of abuse and addiction is extremely complex. Research is only beginning to elucidate the nature of this relationship and its clinical implications. At present, practical management is based primarily on clinical experience and anecdotal observations. In part I of this two-part series (published last month), the authors explored the epidemiology of substance abuse in the cancer population, provided definitions of addiction and abuse appropriate for the oncology setting, and offered guidelines for the assessment of aberrant drug-taking behavior. In this second part, the authors provide recommendations for the evaluation and treatment of patients with cancer who have a history of substance abuse. Suggested therapeutic goals are outlined, and plans for inpatient and outpatient management and detailed.     

The HLD (CalMod) index and the index question

Twenty free-ranging guanaco (Lama guanicoe) in Chubut Province, Argentina, were immobilized for health evaluations. All but two animals appeared to be in good condition. Hematology, serum chemistry, and vitamin and mineral levels were measured, and feces were evaluated for parasites. Serology tests included bluetongue, brucellosis, bovine respiratory syncitial virus, bovine viral diarrhea/mucosal disease, equine herpesvirus 1, infectious bovine rhinotracheitis, Johne's disease (Mycobacterium paratuberculosis), foot and mouth disease, leptospirosis (17 serovars), parainfluenza-3, and vesicular stomatitis. Blood samples from 20 domestic sheep (Ovis aries) maintained in the same reserve with the guanaco were also collected at the same time for serology tests. No guanaco had positive serologic tests. Sheep were found to have antibody titers to bovine respiratory syncytial virus, Johne's disease, leptospirosis, and parainfluenza-3. There was no apparent difference in external appearance or condition, or statistical difference in blood test values, between the animals that were positive or negative for parasite ova.     

A1 is a constitutive and inducible Bcl-2 homologue in mature human neutrophils

Digestion of blood within the mosquito midgut is mediated primarily by a series of proteases, and several previous studies have described protease activity within homogenates of the midgut of the malaria vector Anopheles stephensi. We have expanded on these previous data by resolving protease isoforms from the midgut as well as the hemolymph of adult An. stephensi mosquitoes via gel electrophoresis and zymography. Using this procedure, we have been able to identify multiple isozymes of trypsin, chymotrypsin, and aminopeptidase. We were able to detect an increase in the intensity of some of these protease bands plus the appearance of new bands 24 hr after mosquitoes had taken a blood meal. Furthermore, we detected 2 endogenous trypsin isozymes within the hemolymph. There was no upregulation of these hemolymph isozymes after a blood meal, thus suggesting that they may not be involved in digestion of the blood meal by the mosquito.     

10 years' neuroblastoma screening in Europe: preliminary results of a clinical and biological review from the Study Group for Evaluation of Neuroblastoma Screening in Europe (SENSE)

Between January 1986 and May 1996, 870,313 children were tested in European neuroblastoma (NB) screening programmes. Among these children, 82 cases of NB (age range 4-24 months, median 11 months) were detected by screening. 83% of the patients had localised NB and 17% were diagnosed with generalised NB (stage 4, 10%; stage 4s, 7%). Unfavourable biological markers (MYCN amplification, loss of heterozygosity (LOH) 1p36, DNA di/tetraploidy) were observed in 14% of 76 biologically examined cases. The median follow-up time of all the patients was 21.5 months (range 1-101 months). To date, 69 patients are in complete remission (CR) and 2 patients have died due to therapy (stage 4, 1 patient; stage 3, 1 patient with unfavourable markers). Apart from screened patients, 16 other patients with NB were found who had previously had a normal screening test, i.e. 'false negative' patients (age range 10-41 months, median 31.5 months). The median interval between screening and diagnosis was 24.5 months (range 6-35 months). 11 of the 'false negative' patients suffered from generalised NB (stage 4) and 5 had localised NB at diagnosis. Unfavourable biological markers were observed in 7/12 patients. 5 patients have died, 2 achieved partial remission and 9 CR. 9 of the 11 patients with unfavourable biological markers diagnosed due to NB screening are currently in CR. It is very likely that, among the patients without unfavourable biological markers, we detected tumours which may have regressed spontaneously. These children may have undergone 'unnecessary,' but unavoidable, diagnostic procedures and therapy. To reduce the number of 'false negative' patients, a later screening could be helpful and should be evaluated.     

Influence of bearing stiffness on the static properties of a planetary gear system with manufacturing errors

Hybrid finite element analysis was used to analyze the influence of bearing stiffness on the static properties of a planetary gear system with manufacturing errors. The effects of changes in stiffness were similar for most of the manufacturing errors. State variables were most affected by the stiffness of the planet bearings. Floating either the sun or carrier helps to equal load sharing and minimizes the critical tooth stress. The effects of a floating sun and carrier are similar, but it is not recommended that both float, because this can induce greater critical tooth stress. Planet bearing stiffness should be optimized. Both load sharing and critical tooth stress should be considered to determine optimal bearing stiffness.