Infanticide risk and the evolution of male-female association in primates

Year-round association between adult males and females is common in primates, even though internal gestation and lactation predispose males to mate-desertion in the majority of mammals. Because there is little a priori support for alternative explanations, we hypothesized that permanent male-female association in primates serves to reduce the risk of infanticide by strange males whenever females and infants are closely associated. For a phylogenetic test of this hypothesis, we reconstructed the evolution of male-female and female-infant association among primates. The results of Maddison's concentrated changes test confirmed the prediction that mother-infant association, as opposed to infant parking, and female-male association did not evolve independently. Changes in litter size and activity, in contrast, were not significantly associated with evolutionary changes in male-female association. Thus, we demonstrate a fundamental link between primate life history and social behaviour, explain the most basic type of variation in primate social organization, and propose an additional determinant of social organization that may also operate in other mammals.     

Mapping functional brain development: Building a social brain through interactive specialization.

The authors review a viewpoint on human functional brain development, interactive specialization (IS), and its application to the emerging network of cortical regions referred to as the social brain. They advance the IS view in 2 new ways. First, they extend IS into a domain to which it has not previously been applied--the emergence of social cognition and mentalizing computations in the brain. Second, they extend the implications of the IS view from the emergence of specialized functions within a cortical region to a focus on how different cortical regions with complementary functions become orchestrated into networks during human postnatal development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Accelerated evolution of cytochrome b in simian primates: adaptive evolution in concert with other mitochondrial proteins?

We have devised a practical, sensitive and specific method for simultaneous measurement of free thyroxine (FT4) and free triiodothyronine (FT3) in undiluted serum by direct equilibrium dialysis radioimmunoassay (RIA). Two hundred microliters serum sample was dialyzed against buffer (pH 7.4) for 20 hours at 37 degrees C and approximately 800 microL of the dialysate was used for measuring FT4 and FT3 simultaneously. The assay was set up in polystyrene tubes coated with anti-T4 antibody and available commercially for FT4 measurement (Quest-Nichols Institute, San Juan Capistrano, CA). The mean +/- SE (range) FT4 concentration (ng/dL) was 1.2 +/- 0.04 (0.7.0 to 2.30) in 54 normal subjects. It was significantly increased (3.6 +/- 0.4 [1.8 to 9.6], n = 20) in hyperthyroidism and clearly decreased (0.40 +/- 0.04 [1.10 to 0.70], n = 26] in hypothyroidism. All nonthyroid illness (NTI) patients had normal FT4 except 3, 2 of whom were on amiodarone and 1 had received heparin. Serum FT4 concentration was minimally elevated in 18 newborn cord blood serum (1.40 +/- 0.08 [0.90 to 2.2], cf. normal p < .05). The mean serum FT3 concentration (pg/dL) was 285 +/- 10 (134 to 454) in 54 normal sera. It was clearly increased in hyperthyroidism (1033 +/- 98 [593 to 2134], n = 20, p < .001). However, serum FT3 varied widely in hypothyroidism (27 to 597, mean 235 +/- 24, NS) as did serum total T3 (19 to 175). Interestingly, however, the mean serum FT3 concentration was normal (273 +/- 28 [62 to 575, NS]) in 25 NTI patients. All of these patients had low serum total T3 (46 +/- 5.0 [10 to 84], ng/dL; normal 84 to 160, p < 0.001), while FT3 was clearly normal in 21 of 25 patients and low in the remaining 4 patients. Similarly, among 18 newborn cord blood sera serum FT3 concentration was normal in 15 and subnormal only in the remaining 3 while all had clearly subnormal total T3 (28 to 74 ng/dL). CONCLUSIONS: (1) A practical, sensitive, and specific assay for simultaneous measurement of FT4 and FT3 is described; (2) FT3 is consistently elevated in hyperthyroidism while FT4 is elevated in most (approximately 85%) cases; (3) FT4 is consistently decreased in hypothyroidism but FT3 varies widely; (4). Serum FT3 concentration is normal in approximately 83% of patients with the low T3 syndrome in NTI and newborn cord blood serum. These data suggest that normal FT3 may explain clinical euthyroidism in many patients with the low T3 syndrome.     

Organization and evolution of C4 and CYP21 genes in primates: importance of genomic segments

The evolutionary relationship between two central major histocompatibility complex (MHC) genes, C4 and CYP21, was investigated by employing pulsed field gel electrophoresis (PFGE) and conventional restriction fragment length polymorphism (RFLP) analyses in human and nonhuman primates. Using Taq I in conjunction with C4 and CYP21 probes, it has been found that there are four major types of C4 genes [defined by 7.0, 6.4, 6.0, and 5.4 kilobases (kb) Taq I fragments] and two major types of CYP21 genes (3.7 and 3.2 kb fragments) in human and nonhuman primates including chimpanzee, gorilla, and orangutan. All of the eight possible combinations of C4 and CYP21 genes can be identified on one or more human ancestral haplotypes (AH). It is concluded that each of the major types of C4 and CYP21 (and each of the combinations between these) predated human speciation. PFGE analysis with Mlu I and Pvu I suggested that each C4+CYP21 segment has a specific length of 30-50 kb and that each AH carries one, two, three, or even more segments. In the case of C4, it is important to note that there is no simple relationship between the RFLP and the protein classifications. Thus, at least some of the expressed polymorphisms could be relatively recent in that they are carried by the same or different gene types. These findings are consistent with the hypothesis that MHC AHs have been formed from a large pool of specific genomic segments and that further haplospecific polymorphism has developed subsequently.     

Visual input and lateralization of brain function in learning in the chick

Several lines of evidence (biochemical, neuroanatomical, electrophysiological, and behavioural) have indicated a critical role for the intermediate medial hyperstriatum ventrale of the chick forebrain in the acquisition of a passive avoidance response. Previous lesion studies indicated that bilateral or left, but not right, pretraining intermediate medial hyperstriatum ventrale lesions interfere with the acquisition of this task. We have further analysed this asymmetrical involvement of the intermediate medial hyperstriatum ventrale by use of a monocular learning protocol and intermediate medial hyperstriatum ventrale lesions (sham, bilateral, or unilateral). The results indicated that there is interocular transfer of information of passive avoidance learning between the two eye systems, with a tendency to be more successful from the right eye system to the left than in the opposite direction. As in binocular conditions, bilateral pretraining intermediate medial hyperstriatum ventrale lesions impair learning in monocularly trained animals. Unilateral lesions to either left or right monocularly trained experimental animals resulted in amnesia when they were made to the right intermediate medial hyperstriatum ventrale and the chicks were trained/tested with the left eye open. These results indicate that, although right intermediate medial hyperstriatum ventrale lesions do not result in amnesia in binocular animals, this region is capable of participating in memory acquisition processes. They also suggest a connection between lateralization of intermediate medial hyperstriatum ventrale function in passive avoidance learning and the behavioural and structural visual asymmetries known to occur in chicks.     

Visual slow brain potentials in children with attention deficit disorder

Using a two-stimulus reaction time paradigm, with two separate reward conditions (contingent and noncontingent), we compared slow wave brain potentials (ERPs) in 144 children with attention deficit disorder (ADD) and 30 normal control children. This article reviews the findings during the 900 msec visual warning stimulus. As we had expected, based on ERP work of Forth and Hare (1989) and Raine, Venables and Williams (1990), and on previous work from our own laboratory, the group differences were found in the negative slow wave portions of the ERP complex during the contingent reward condition but not during the noncontingent condition. Aggressive hyperactive subjects with attention deficit disorder (ADDHA) were discriminated from nonaggressive subjects (including control subjects) during the contingent reward condition in the following ways: (1) greater fronto-central negativity (640-900 msec slow wave) and (2) greater right parietal than left parietal negativity (430-750 msec slow wave). All ADD subgroups, when compared to control (CONTR) subjects, showed greater slow wave negativity (700-900 msec) at the midline occipital electrode site during the contingent reward condition. This could be explained in part as an IQ effect on ERPs reflecting the IQ difference between the ADD subgroups and the controls. These slow wave findings seem to relate to attentional problems of these children. They are discussed in terms of a psychobiological model of inhibition/disinhibition and appetitive activation.     

Hernia registers and specialization

Registration of hernia surgery is useful in the demonstration of outcome quality provided reoperation is linked to the primary procedure. Prerequisites for a hernia register are discussed based on Swedish experience. Evidence indicates that register participation reduces reoperation rate and increases costeffectiveness. Monitoring of outcome quality is important for both specialized and nonspecialized hernia surgeons. Registers of the type discussed may assist general surgeons in their efforts to achieve levels defined by experts.     

In vivo proton magnetic resonance spectroscopy for metabolic changes in brain during chronic cerebral vasospasm in primates

OBJECTIVE: To study how neuronal cells are affected by development of chronic cerebral vasospasm after subarachnoid hemorrhage (SAH), the changes in neuronal metabolites during development of vasospasm were evaluated by in vivo localized proton magnetic resonance spectroscopy (MRS) in primates. METHODS: SAH was produced by introduction of a blood clot around the right middle cerebral artery and the right side of the circle of Willis. MRS experiments were performed before SAH and on Days 7 and 14 after SAH. Multislice magnetic resonance images were obtained to locate the volume of interest (1.0 cm3) in the bilateral parietal regions. The peak areas for choline compounds, the sum of creatine and phosphocreatine, and N-acetyl-aspartate were calculated. RESULTS: Angiograms revealed approximately 50% reduction of vessel caliber for the right main cerebral arteries on Day 7. Magnetic resonance imaging revealed no apparent cerebral infarction, even in the spasm-side hemisphere. MRS revealed a significant (P < 0.05) reduction of the N-acetyl-aspartate/creatine and phosphocreatine ratio on Days 7 and 14 and a significant increase in the choline/creatine and phosphocreatine ratio on Day 7, in the spasm-side parietal region. In the sham-operated animals, there were no significant changes in these ratios in the bilateral parietal region on Days 7 and 14 after the operation. CONCLUSION: The results suggested that the development of cerebral vasospasm after SAH caused ischemic injury in a subpopulation of neuronal cells, even when no apparent cerebral infarction was shown. Proton MRS may be useful to evaluate how neuronal cells are affected by the ischemic insult during development of vasospasm in clinical situations.     

Cystoscopy in nonhuman primates

Cystoscopy can be routinely performed in female rhesus macaques using a pediatric cystoscope. It reveals no major differences between the rhesus and human bladder. Ureteral physiology is also similar to that of man.     

Hemispheric specialization in commissurotomized man.

Following surgical division of the neocortical commissures in humans, it is possible to test independently the 2 cerebral hemispheres on the same task and thus determine directly their competence for various cognitive skills. Studies examining the limits of language expression and comprehension in the minor hemisphere of these patients are reviewed. Evidence of right-hemispheric superiority for the perception of spatial and part-whole relations is discussed with respect to theories postulating a basic dissimilarity in the manner by which information is processed in the major and minor hemispheres. Data are also reviewed which suggest that competition between the 2 hemispheres for control of the motor system is resolved in favor of the hemisphere dominant for the cognitive function required in the task. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Otx1 and Otx2 in the development and evolution of the mammalian brain

In the last decade, a number of genes related to the induction, specification and regionalization of the brain were isolated and their functional properties currently are being dissected. Among these, Otx1 and Otx2 play a pivotal role in several processes of brain morphogenesis. Findings from several groups now confirm the importance of Otx2 in the early specification of neuroectoderm destined to become fore-midbrain, the existence of an Otx gene dosage-dependent mechanism in patterning the developing brain, and the involvement of Otx1 in corticogenesis. Some of these properties appear particularly fascinating when considered in evolutionary terms and highlight the central role of Otx genes in the establishment of the genetic program defining the complexity of a vertebrate brain. This review deals with the major aspects related to the roles played by Otx1 and Otx2 in the development and evolution of the mammalian brain.     

Fetal islet xenotransplantation in rodents and primates

(E)-2'-deoxy-2'-(fluoromethylene) cytidine (FMdC), a novel inhibitor of ribonucleotide-diphosphate reductase, has been shown to have anti-tumor activity against solid tumors and sensitize tumor cells to ionizing radiation. Pentoxifylline (PTX) can potentiate the cell killing induced by DNA-damaging agents through abrogation of DNA-damage-dependent G2 checkpoint. We investigated the cytotoxic, radiosensitizing and cell-cycle effects of FMdC and PTX in a human colon-cancer cell line WiDr. PTX at 0.25-1.0 mM enhanced the cytotoxicity of FMdC and lowered the IC50 of FMdC from 79 +/- 0.1 to 31.2 +/- 2.1 nM, as determined by MTT assay. Using clonogenic assay, pre-irradiation exposure of exponentially growing WiDr cells to 30 nM FMdC for 48 hr or post-irradiation to 0.5 to 1.0 mM PTX alone resulted in an increase in radiation-induced cytotoxicity. Moreover, there was a significant change of the radiosensitization if both drugs were combined as compared with the effect of either drug alone. Cell-cycle analysis showed that treatment with nanomolar FMdC resulted in S-phase accumulation and that such an S-phase arrest can be abrogated by PTX. Treatment with FMdC prior to radiation increased post-irradiation-induced G2 arrest, and such G2 accumulation was also abrogated by PTX. These results suggest that pharmacological abrogation of S and G2 checkpoints by PTX may provide an effective strategy for enhancing the cytotoxic and radiosensitizing effects of FMdC.     

Visual motion perception after brain damage: II. Deficits in form-from-motion perception

We investigated form-from-motion perception (FFM perception) in a sample of 39 patients with acquired brain damage. Pronounced FFM deficits were found in two patients (FM1 and FM2) with biparietal lesions. Both patients were able to identify the relevant figure, when it was not embedded in obstructive texture. Moreover, they could localize the figures in the FFM condition, although they could not reliably identify them. The two patients had normal motion coherence thresholds. Their performance in a static figure-ground task did not differ from that of other patients. These findings imply that the FFM deficits are not caused by impairment of basic visual motion or form perception but are the consequence of damage to a parietal brain structure involved in the combined analysis of visual motion and form information. The nature and functional role of this brain structure as well as the implications of our results for models of FFM perception are discussed.     

What can monotremes tell us about brain evolution?

The present review outlines studies of electrophsyiological organization, cortical architecture and thalmocortical and corticocortical connections in monotremes. Results of these studies indicate that the neocortex of monotremes has many features in common with other mammals. In particular, monotremes have at least two, and in some instances three, sensory fields for each modality, as well as regions of bimodal cortex. The internal organization of cortical fields and thalamocortical projection patterns are also similar to those described for other mammals. However, unlike most mammals investigated, the monotreme neocortex has cortical connections between primary sensory fields, such as SI and VI. The results of this analysis lead us to pose the question of what monotremes can tell us about brain evolution. Monotremes alone can tell us very little about the evolutionary process, or the construction of complex neural networks, as an individual species represents only a single example of what the process is capable of generating. Perhaps a better question is: what can comparative studies tell us about brain evolution? Monotreme brains, when compared with the brains of other animals, can provide some answers to questions about the evolution of the neocortex, the historical precedence of some features over others, and how basic circuits were modified in different lineages. This, in turn, allows us to appreciate how normal circuits function, and to pose very specific questions regarding the development of the neocortex.     

Hemispheric specialization and ear advantages in processing speech.

Reviews research on the hemispheric asymmetry model of relative ear advantages in the processing of auditory stimuli. Physiological studies of activation of the hemispheres in humans support left-hemisphere speech-processing specialization and contralateral sound field dominance. Electrophysiological studies in animals, effects of commissurotomy, hemispherectomy, and unilateral temporal lobe lesions on dichotic performance in humans, as well as stimulus dominance effects in intact Ss indicate that the assumption of ipsilateral sensory pathway suppression during competitive stimulation is unwarranted. Dichotic presentation is not necessary to produce a right-ear advantage (REA), and selective attention to one or the other ear frequently tends to alter the magnitude of the REA. A modified structural model that incorporates the effects of directed attention is proposed. (3? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Paternalistic behavior in primates.

Concerned with interactions between adult male and infant nonhuman primates and includes both field and laboratory data. Potential experimental factors involved in paternalistic behavior are listed and a few of these factors are shown to be of measurable importance in the development of paternal-like behaviors. These paternal-like behaviors, in turn, are seen as important in the behavioral development of the infant in natural and seminatural groups. (81 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Brain telesiimulation in primates.

Purports to accurately state the nature and cost of brain telestimulation research with primates. Advantages and disadvantages are presented. 3 primate telestimulation systems are described: System I by M. Maurus for use on the squirrel mondey; System II by J. M. Delgado, et al. (see 43:4) for use on the rhesus monkey and the human; and System III by H. Warner, et al., for medium-sized monkeys, and the anthropoid apes. The needs emphasized for successful application of telestimulation are: (a) an electronics engineer or technician, experienced in radio frequency work; (b) a specially designed room to absorb all reflections and produce a homogeneous radio frequency field; and (c) equipment to service and maintain the radio frequency apparatus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual evoked potentials in phenylketonuria: association with brain MRI, dietary state, and IQ

Tumor-associated glycoprotein 72 is a high-molecular-weight sialomucin that is expressed selectively in various adenocarcinomas, including those of the prostate. We utilized the monoclonal antibodies B72.3 and CC49 to examine the expression of TAG-72 in high-grade prostatic intraepithelial neoplasia (PIN), localized adenocarcinomas (pathologic stages B and C), as well as matching primary and nodal lesions from patients with stage D adenocarcinomas. Immunoreactivity within PIN lesions was detected within 20 (87%) and 17 (74%) of 23 specimens immunostained with B72.3 and CC49, respectively. Benign epithelium and stromal tissue did not immunostain with either antibody at the concentrations tested. Immunostaining was detected within the malignant cells in 30 (77%) and 35 (90%) of 39 localized adenocarcinomas using B72.3 and CC49, respectively. Immunostaining was localized to the cytoplasm and cellular membranes of the malignant cells and within the lumen of malignant glands. Seven of 17 (41%) primary lesions from patients with stage D adenocarcinomas demonstrated immunoreactivity when stained with B72.3. Immunoreactivity was detected in 8 of 10 (80%) of these tissues immunostained with CC49. Within nodal lesions obtained from these patients, immunostaining was observed in 3 of 17 (18%) and 6 of 10 (60%) of the specimens immunostained with B72.3 and CC49, respectively. We used a semiquantitative technique to compare the extent of immunoreactivity among well-differentiated (Gleason score < 6), moderately differentiated (Gleason 6-7), and poorly differentiated (Gleason score > 7) tumors. We observed an inverse correlation of TAG-72 expression to Gleason scores. Furthermore, TAG-72 expression was reduced in the matching primary and metastatic lesions of stage D adenocarcinomas as compared to localized lesions.(ABSTRACT TRUNCATED AT 250 WORDS)