Spontaneous tumours in tree shrews (Tupaia belangeri): population studies

Although some studies have reported that reinforcement can strengthen people's behaviour without their awareness, most studies that have incorporated adequate procedures for assessing awareness have been unsuccessful. Using rigorous procedures, we report two studies designed to provide more scope for learning without awareness by making the reinforcement contingency as unobtrusive as possible. Subjects were told that the experiment was on ESP, and that they were to say which of two words the experimenter was thinking about. In fact, reinforcement was contingent on the loudness of the subject's voice when responding. Even though subjects reported no awareness of a relationship between trial outcomes and their behaviour, the probability of the reinforced responses increased significantly over trials in both experiments. These results support the view that reinforcement can occur without awareness.     

Cryptococcosis in tree shrews (Tupaia tana and Tupaia minor) and elephant shrews (Macroscelides proboscides)

OBJECTIVE: To determine the relation between metabolic and anthropometric parameters and circulating leptin concentrations in women with polycystic ovary syndrome (PCOS). DESIGN AND PATIENTS: Correlation of fasting serum leptin concentrations with anthropometric measures and multiple metabolic parameters including insulin and glucose responses to a 2-hour 75-g oral glucose tolerance test (OGTT) in 85 women with PCOS (17-36 years, body mass index (BMI) 29.9 +/- 0.9 kg/m2, mean +/- SD) and 18 control women (25-47 years, BMI 25 +/- 1.7 kg/m2). Diagnostic criteria for PCOS: characteristic ovarian morphology on ultrasound plus at least two of (1) elevated serum testosterone; (2) elevated serum androstenedione; and (3) reduced serum SHBG concentrations. MEASUREMENTS: Concentrations of androgens, lipids, PRL, gonadotrophins, and leptin were measured in the baseline fasting blood sample from an OGTT. Insulin and glucose were measured throughout OGTT. Serum leptin concentrations were measured by radioimmunoassay. RESULTS: Log leptin levels in the PCOS group correlated significantly with BMI (r = 0.85, P < 0.0001) and with 8 other parameters including waist/hip ratio (r = 0.51, P = 0.0005). By stepwise regression analysis, only BMI (P < 0.0001) and plasma high density lipoprotein concentration (P = 0.02) were independently correlated with log leptin levels, both positively. There was no effect of fat distribution, as measured by waist/ hip ratio, on leptin concentrations. Comparison of control subjects to a BMI-matched subgroup of 55 PCOS subjects revealed significantly higher circulating concentrations of LH, testosterone, DHEAS, progesterone and androstenedione, and higher glucose and insulin responses to OGTT in the PCOS group. Leptin levels were not different between the PCOS subgroup and control group (14.8 +/- 1.3 vs 12.1 +/- 2.3 micrograms/l, mean +/- SE, P = 0.26) and the relation of BMI to leptin levels determined by linear regression analysis also did not differ between the two groups. CONCLUSIONS: Our results indicate that circulating leptin concentrations in women with PCOS, a condition characterized by hyperandrogenaemia, increased LH concentrations and insulin resistance, are strongly related to BMI and not independently affected by circulating levels of insulin, gonadotrophins or sex hormones.     

Anatomy and function of the reproductive tract in the captive male tree shrew (Tupaia belangeri)

The reproductive anatomy of the male tree shrew (Tupaia belangeri) was examined and compared with other Tupaiidae. The testes are located prepenially in a pigmented scrotum which is fused to the base of a pendulous penis. The terminal portion of the vas deferens is differentiated into an ampullary gland and joins the duct of the seminal vesicle to form a short ejaculatory duct. The prostate is a compact bilateral body drained by a main collecting duct. In the aggregate, these features indicate that the reproductive system in Tupaia is primate in character. Testicular function in tree shrews is affected by both social and seasonal factors. When males were housed communally, the majority exhibited testicular degeneration accompanied by a loss in the weight and fructose content of the seminal vesicles and in pigmentation of the scrotum. These changes may be due to the presence of dominant conspecifics since animals kept in isolation undergo normal sexual development. Animals captured throughout the year and isolated show seasonal fluctuations in androgenic and spermatogenic function. Reproductive capacity is maximal during the winter and minimal during the summer. Local environmental factors appear to regulate reproductive function so that the greatest number of births occur during the dry season.     

Aspects of masticatory form and function in common tree shrews, Tupaia glis

Tree shrews have relatively primitive tribosphenic molars that are apparently similar to those of basal eutherians; thus, these animals have been used as a model to describe mastication in early mammals. In this study the gross morphology of the bony skull, joints, dentition, and muscles of mastication are related to potential jaw movements and cuspal relationships. Potential for complex mandibular movements is indicated by a mobile mandibular symphysis, shallow mandibular fossa that is large compared to its resident condyle, and relatively loose temporomandibular joint ligaments. Abrasive tooth wear is noticeable, and is most marked at the first molars and buccal aspects of the upper cheek teeth distal to P2. Muscle morphology is basically similar to that previously described for Tupaia minor and Ptilocercus lowii. However, in T. glis, an intraorbital part of deep temporalis has the potential for inducing lingual translation of its dentary, and the large medial pterygoid has extended its origin anteriorly to the floor of the orbit, which would enhance protrusion. The importance of the tongue and hyoid muscles during mastication is suggested by broadly expanded anterior bellies of digastrics, which may assist mylohyoids in tensing the floor of the mouth during forceful tongue actions, and by preliminary electromyography, which suggests that masticatory muscles alone cannot fully account for jaw movements in this species.     

Pattern of cell death during optic cup formation in the tree shrew Tupaia belangeri

Literature has much to offer the psychotherapist. This paper has discussed some lessons for the psychotherapist contained in Franz Kafka's short story, The Metamorphosis. The therapist, like the therapist-reader of this story, can empathize with Gregor's monstrous change but still must hold him personally accountable. At the same time, the therapist-reader becomes increasingly impressed with the malignant nature of the Samsa household, and its role in generating Gregor's capacity for self-deception. The story also instructs about the paradox of catastrophe: Gregor is treated no less respectfully after his metamorphosis than he was before it. The therapist is thereby reminded of the centrality of feelings in human affairs. The constriction of Gregor's space does not cut him off from human feeling; rather, Gregor's inability to access, know, and take responsibility for his own feelings, especially his destructive ones, results in his constrictedness and detachment. In thinking about the story as dream, or in imagining a patient's account of a reality situation as if it were a dream, unseen mental process and content become more apparent. The disgusting, loathsome arrangements that people make with each other can evoke, be it in the therapist-reader or the therapist, reactions of aversion or hate. Such arrangements become more understandable when the importance, sometimes the necessity, of human attachment is appreciated. And finally, Kafka's The Metamorphosis alerts us to a sometimes but powerful preference and countertransference pitfall: we don't want to be bugged.     

Prenatal gonadal hormones and sex differences in human behavior.

Summarizes the literature on perinatal hormone influences in infrahuman mammals, reviews in detail studies on perinatal hormone influences on human behavior, and summarizes methodological procedures that have been used to compensate for problems inherent in research on clinical populations. Several studies provide evidence suggesting that some sex differences in human behavior may be related to prenatal hormone levels. In light of methodological advances and the growing number of studies in this area, it may soon be possible to define human hormone–behavior relations in sufficient detail to allow strong links to research on perinatal hormone effects in other species. Given recent identification of neural sex differences that may underlie behavioral sex differences in infrahuman mammals, such links could lead to greater understanding of the neural basis of sexually dimorphic behaviors in humans. (4 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cerebellar corticonuclear fibers of the paramedian lobule of tree shrew (Tupaia glis) with comments on zones

Following a series of lesions in dorsal (DPML) and ventral (VPML) divisions of tree shrew (Tupaia) paramedian lobule (PML), the distribution of degenerated axons within the deep cerebellar nuclei was determined using the Fink and Heimer ('67) method. Damage to PML produced axonal degeneration in lateral (NL), anterior interposed (NIA), and posterior interposed (NIP) cerebellar nuclei. No degenerated fibers could be traced to either the medial cerebellar nucleus or vestibular complex, via juxtarestiform body, from lesions in PML. Corticonuclear fibers to NL, NIA, and NIP from PML cortex are topographically organized. Subsequent to lesions of lateral DPML, axonal debris is found in rostral and medial NL, while the lateral edge of VPML projects primarily into medial NL. According to the terminology of Voogd ('69) these lateral regions of PML represent the D zone. The NIP receives corticonuclear input from a relatively wide middle area of both portions of PML, interpreted as the C2 zone. There is some evidence which suggests that medial portions of the C2 area of DPML project into more lateral areas of NIP, while lateral regions of this zone in DPML are related to more medial NIP. This projection pattern is invited for the C2 area of VPML; medial C2 to medial NIP, lateral C2 to lateral NIP. Corticonuclear fibers of PML which enter NIA appear to arise from a narrow, irregular, partially discontinuous strip of cortex located at the interface of the D and C2 areas in lateral PML and from a wider, more regular region in the most medial areas of this lobule. These represent, respectively, the C3 and C1 zones. Although an overall pattern of zones is present, there is evidence to suggest that their spatial organization differs from DPML to VPML. The zonal patterns appears to be more obvious in VPML, while this pattern for DPML is less distinct. This is interpreted as indicating that either (1) zones C1--C3 overlap to a greater degree in DPML than in VPML, or (2) zones C1 and C3 may converge in rostral DPML, partially obliterating the intervening zone C2. The different ways in which zonal terminology is applied to both corticonuclear and certain of the afferent cerebellar systems are discussed.     

Steroidal modulation of scent investigation and marking behaviors in male and female ferrets (Mustela putorius furo).

Gonadectomized male and female ferrets (Mustela putorius furo) given either testosterone propionate (TP) or oil vehicle preferred to investigate the side of a test cage previously soiled by a breeding male or female as opposed to a clean side. Male and female ferrets receiving TP showed more urogenital wiping than oil-treated animals in either side of the test cage. In a 2nd experiment, ferrets treated sequentially with TP, oil, and estradiol benzoate (EB) were given simultaneous access to sides of a test cage previously soiled by either a breeding female or male. Either EB or TP treatment of females and TP treatment of males facilitated the investigation of odors of opposite-sex ferrets. Females given TP and males given either TP or EB showed increased urogenital wiping in both sides of the test cage. Sex steroids modulate scent investigation and marking in adult ferrets in a sexually differentiated fashion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Causes of scent marking in female golden hamsters (Mesocricetus auratus): Specific signals or classes of information?

Odor-elicited scent marking is common among mammals, but the proximate causes of marking are not well understood. Scent marking by female hamsters in response to 8 different male odors was investigated. Two odors (flank, mouth) increased flank marking and 2 (flank, rump) increased vaginal marking; in the latter case the effects of flank and rump odors were additive. Two odors (feces, urine) decreased flank marking but did not affect vaginal marking; other odors (foot, ear, ano-genital) had no influence on either scent-marking behavior. Results show that scent marking by females is influenced by a limited number of male odors, suggesting specific effects of particular odors. Classes of information (such as sexual identity) were not relevant causes of scent marking, as some odors containing such information were effective but others were not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How tree shrews (Tupaia belangeri) perform in a searching task: Evidence for strategy use.

This study investigated how male tree shrews (Tupaia balngeri) performed in a searching task while in their home cages and assessed whether different food distributions affected their performance. The animals were faced with a holeboard containing 9 food sources arranged in a 3 X 3 matrix or in 3 clusters, each containing 3 sources. Animals tended to start and end the trials from preferred locations, thereafter solving the task by strategically organizing the reward collection according to a minimum-distance principle. In the cluster configuration, they visited the sources hierarchically. Food distribution did not affect the performance. Comparison with data from mice and capuchin monkeys revealed that tree shrews and capuchins solved the task in a similar strategic way, whereas mice did not. These findings attract particular attention because of the phylogenetic position of tree shrews, which are regarded as closely related to primates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interactive effects of behavior and reproductive hormones on sex differences in risk for coronary heart disease.

Examines factors accounting for why women in most industrialized countries are protected from coronary heart disease (CHD) relative to men, focusing on the effects of female reproductive hormones (i.e., estrogens) on lipid and lipoprotein metabolism and blood pressure. Epidemiological studies that statistically adjust for sex differences in lipids, blood pressure, and smoking status cannot explain sex differences in CHD morbidity and mortality. Data also show elevated risk of myocardial infarction and stroke among women who use oral contraceptives. Men who are prescribed estrogens have elevated risk of CHD, and case-control studies show that male CHD patients have elevated estradiol, compared to controls. Simple main-effect models of female protection from CHD are inadequate. Reproductive hormones are important determinants of protection from CHD, and behavioral characteristics can influence the effects of reproductive hormones on CHD risk factors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantification of salmon alpha- and thyrotropin (TSH) beta-subunit messenger RNA by an RNase protection assay: regulation by thyroid hormones

Brightness discrimination of black-white stimuli (1-37 Cd/m; CIE-31 chromatic coordinate X = 0.340, Y = 0.304) were studied using choice conditioning paradigm in two monkey (Macaque Rhesus). Confusion matrices were composed of probabilities of instrument responses to conditioned and differential stimuli in ten series in which one of the ten intensities was employed as a conditioned one. Confusion matrices were transformed into the correlation matrices between the vectors corresponding to the stimuli. Factor analysis of correlation matrices revealed two-dimensional circular structure of monkey's brightness perceptual space. This space was principally similar with that in humans, fishes, and rabbits. Two eigenvectors which constituted two-dimensional Euclidean space of brightness can be interpreted as bright and dark neuronal channels.     

Correlation of the production of gonadotropic and sex hormones in boys and girls during sex maturation

There is an early period of puberty in boys at the age of 10 to 13, accompanied by an increase in the level of follicle stimulating hormone and a low secretion of luteinizing hormone and testosterone, with no secondary sexual signs. The beginning of an increase in the luteinizing hormone and testosterone concentration in boys coincides with the development of secondary sexual signs. The stabilization of the level of luteinizing hormone takes place in boys already at the 2nd degree of the sexual development. The secretion of luteinizing hormone at this point corresponds already to the normal level in adult men. The level of testosterone in the blood continues to increase and does not reach its definitive level until after the age of 17, or at the 5th degree of sexual development. Like in boys, the increase of the follicle stimulating hormone in girls precedes the increase of the luteinizing hormone secretion. The beginning of the increase in the follicle stimulating hormone coincides with an increase in the level of estrogens and testosterone in the blood, and with the appearance of secondary signs of sexual maturation. The increase of the luteinizing hormone secretion takes place later in girls than in boys and is accompanied by a new and significant increase in the level of estrogens in the blood. At the 2nd degree of sexual development, the level of testosterone in the blood of girls is substantially higher than at the other stages.     

Chromosomal evolution and zoogeographic origin of southeast Asian shrews (genus Crocidura)

Genome scanning is a technique designed to uncover a net genetic difference between otherwise identical DNA samples. As such, it can be used to directly identify the site of a gene mutation, facilitating the cloning of DNA fragments from that site. Unlike other conventional positional cloning methods, one-dimensional genome scanning does not require prior knowledge of the location of the gene or mutation nor does it require closely linked markers. Rather, this method can directly identify the site of a net genomic change, such as a deletion or duplication caused by a mutation. Thus, the genome scanning method can be used in place of classic positional cloning strategies because prior positioning or mapping of the objective gene is unnecessary. By using this approach, we have identified and cloned a DNA fragment duplicated in the p(un) mutation of the mouse pink-eyed dilution locus (Brilliant et al., Science 1991, 252, 566-569). However, no other similar attempt using one-dimensional genome scanning has been reported so far, in spite of the simplicity of the procedure and its success in identifying and ultimately characterizing the pink-eyed dilution gene of the mouse. The lack of other reports of its success are perhaps not because of the practical difficulties of this method, but may be due to the false presumption that the probability for directly identifying the mutation site using genome scanning is extremely low. The theoretical probability was calculated and is presented here.(ABSTRACT TRUNCATED AT 250 WORDS)     

Synthesis and regulation of leukaemia inhibitory factor in cultured bovine oviduct cells by hormones

Group II introns are large, self-splicing RNAs and mobile genetic elements that provide good model systems for studies of RNA folding. The structures and mechanistic functions of individual domains are being elucidated, and long-range tertiary interactions between the domains are being identified, thus helping to define the three-dimensional architecture of the intron.     

Organizing and activating effects of sex hormones in homosexual transsexuals.

The cause of transsexualism remains unclear. The hypothesis that atypical prenatal hormone exposure could be a factor in the development of transsexualism was examined by establishing whether an atypical pattern of cognitive functioning was present in homosexual transsexuals. Possible activating effects of sex hormones as a result of cross-sex hormone treatment were also studied. Female-to-male and male-to-female transsexuals were compared with female and male controls with respect to spatial ability before and after treatment. The data were consistent with an organizing effect, but there was no evidence of an activating effect. Homosexual transsexuals, who prior to hormone treatment scored in the direction of the opposite sex, may have reached a ceiling in performance and therefore do not benefit from activating hormonal effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Control of reproductive behavior by sex steroids in male quail.

Conducted 2 experiments on the ability of different sex steroids to stimulate crowing, strutting, and copulation. Exp I with 32 male Japanese quail was designed to maximize crowing. Intact untreated males and castrated males treated with 2 dosages of testosterone propionate (TP), with 2 dosages of dihydrotestosterone propionate (DHTP), or with oil were tested. The DHTP-treated males crowed extensively; TP-treated males crowed, but to a lesser extent than DHTP-treated males. In Exp II (30 Ss), which was designed to maximize strutting and copulation, males with photically regressed testes were treated with DHTP, DHTP?+?estradiol benzoate (EB), or EB alone and were tested with female partners. The DHTP-treated males did not copulate, but 2 birds strutted. The EB-treated males copulated but did not strut. Males receiving DHTP?+?EB strutted and copulated. These results suggest that (a) copulation in quail may involve conversion of testosterone to estrogen by the brain; (b) crowing and strutting may involve conversion of testosterone to dihydrotestosterone by the brain; and (c) in quail, the different components of male reproductive behavior show divergent patterns of hormone responsiveness, and thus the neural tissues underlying these behaviors have different molecular requirements for activation by steroids. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory for individual scent in hamsters (Mesocricetus auratus) as assessed by habituation methods.

The memory of hamsters (Mesocricetus auratus) for the flank scent of older male hamsters was investigated in a series of habituation experiments. In 2 types of habituation tasks (Exps 1 and 2), male hamsters habituated to the flank scent of 1 male and then increased their level of investigation to that of a novel male; similar results were obtained when the intervals between trials ranged from 1 sec to 2 days. When the test trial was 10 or 21 days after habituation (Exp 3), males discriminated between familiar and novel flank scents at 10 days but not at 21 days. The results demonstrate recognition of familiar and unfamiliar individual odors and excellent memory for these differences. Habituation techniques yield extremely robust results and may be useful for investigations of other aspects of individual signatures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)