Characterization of the oxytocin system regulating affiliative behavior in female prairie voles.

Oxytocin regulates partner preference formation and alloparental behavior in the socially monogamous prairie vole (Microtus ochrogaster) by activating oxytocin receptors in the nucleus accumbens of females. Mating facilitates partner preference formation, and oxytocin-immunoreactive fibers in the nucleus accumbens have been described in prairie voles. However, there has been no direct evidence of oxytocin release in the nucleus accumbens during sociosexual interactions, and the origin of the oxytocin fibers is unknown. Here we show for the first time that extracellular concentrations of oxytocin are increased in the nucleus accumbens of female prairie vole during unrestricted interactions with a male. We further show that the distribution of oxytocin-immunoreactive fibers in the nucleus accumbens is conserved in voles, mice and rats, despite remarkable species differences in oxytocin receptor binding in the region. Using a combination of site-specific and peripheral infusions of the retrograde tracer Fluorogold, we demonstrate that the nucleus accumbens oxytocin-immunoreactive fibers likely originate from paraventricular and supraoptic hypothalamic neurons. This distribution of retrogradely labeled neurons is consistent with the hypothesis that striatal oxytocin fibers arise from collaterals of magnocellular neurons of the neurohypophysial system. If correct, this may serve to coordinate peripheral and central release of oxytocin with appropriate behavioral responses associated with reproduction, including pair bonding after mating, and maternal responsiveness following parturition and during lactation.

Information concentration along the boundary contours of naturally shaped solid objects.

In this study of the informativeness of boundary contours for the perception of natural object shape, observers viewed shadows/silhouettes cast by natural solid objects and were required to adjust the positions of a set of 10 points so that the resulting dotted shape resembled the shape of the original silhouette as closely as possible. For each object, the observers were then asked to indicate the corresponding positions of the 10 points on the original boundary contour. The results showed that there was a close correspondence between the chosen positions of the points and the locations along the boundary contour that were local curvature maxima (convexities or concavities). This finding differs from that of Kennedy and Domander (1985 Perception 14 367-370), and shows that, at least for natural objects, the original hypothesis of Attneave (1954 Psychological Review 61 183-193) is valid--local curvature maxima are indeed important for the perception of shape.

Cleomedes (c. 1st century AD) on the celestial illusion, atmospheric enlargement, and size-distance invariance.

Cleomedes (Kleomedes) is a little-known Greek author (c. 1st century AD) who produced what is probably the earliest extant statement of size-distance invariance. He supported the Stoic philosophy and was concerned to discredit the Epicurean position that we perceive objects as having their true size. He explained the celestial illusion (the apparent enlargement of the sun near the horizon) in two ways: partly as a refractive effect of the atmosphere similar to angular enlargement when looking into water; and partly as a linear enlargement due to increased apparent distance in a misty atmosphere. He is the earliest extant author to offer apparent distance as a clear explanation of the celestial illusion. He attributed these views to Posidonius (c. 135-50 BC). His explanations remained at the geometrical level, and he did not speculate on sensory mechanisms.

Factors associated with untreated remissions from alcohol abuse or dependence.

This paper describes an epidemiologic-based sample of individuals who remitted from alcohol abuse or alcohol dependence, both with and without treatment, to abstinence or moderate drinking. Inspection of the severity, onset, and duration of alcohol problems experienced by these individuals suggests that there may be two primary categories of drinkers with distinct pathways to remission. The first is a population of individuals who experience significant problems for an extended period of time who then resolve to abstinence through the use of treatment services. The second is a population of individuals who drink heavily at some point in their lives, experience some problems, and then "mature out" of this stage in their life as they age and take on other life roles.

Food availability affects behavior but not circulating gonadal hormones in maternal Belding's ground squirrels.

We tested predictions of hypotheses suggesting that the steroid hormones, testosterone (T), progesterone (P), and estradiol (E2), contribute to the energetic regulation of behaviors associated with rearing young in free-living female Belding's ground squirrels (Spermophilus beldingi). We provisioned some female S. beldingi with food rich in fat and calories, and used unprovisioned females as controls. We observed the behavior of females throughout the reproductive cycle, and regularly collected blood samples to measure plasma hormone concentrations. Circulating concentrations of T, P, and E2 were similar in provisioned and unprovisioned females, as were temporal patterns of variation in these hormones. Peaks in rates of nest maintenance and aggressive behavior occurred during gestation and were associated with elevated concentrations of circulating T, P, and E2, raising the possibility that one or more of these hormones mediates behaviors that help females establish maternal nest sites and territories after mating. Temporal patterns of variation in behavior were similar among provisioned and unprovisioned females; however, rates of resting, vigilance, and aggression were higher among provisioned females, whereas unprovisioned females devoted significantly more time to feeding and locomotion. Thus, our data suggest that in maternal S. beldingi, gonadal steroids play a role in mediating behavior associated with raising offspring, but do not facilitate changes in rates of behavior associated with increased energy availability.

Charpentier (1891) on the size-weight illusion.

This paper offers background for an English translation of an article originally published in 1891 by Augustin Charpentier (1852-1916), as well as a summary of it. The article is frequently described as providing the first experimental evidence for the size-weight illusion. A comparison of experiments on the judged heaviness of lifted weights carried out by Weber (1834) and by Charpentier (1891) supports the view that Charpentier's work deserves priority; review of other experimental studies on the size-weight illusion in the 1890s suggests that the idea that the illusion depended on "disappointed expectations," especially with respect to speed of lift, became dominant almost immediately following the publication of Charpentier's paper. The fate of this and other ideas, including "motor energy," in 20th-century research on the illusion is briefly described.

Mental health service use: a comparison of treated and untreated individuals with substance use disorders in Ontario.

OBJECTIVE: To determine the prevalence of and factors associated with mental health service use in the past year among respondents with an alcohol or other drug use disorder in a general population survey of Ontario adults. METHOD: Data were obtained from the 1990/1991 Mental Health Supplement to the Ontario Health Survey, which used the University of Michigan Composite International Diagnostic Interview (UM-CIDI). The current study examined 436 respondents aged 15-64 years who met Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria for a substance use disorder in the past year. The 82 respondents who used services for a mental health or substance abuse problem during the past year were compared with the 354 nonusers. Illness severity, disability, health beliefs and attitudes, and predisposing or enabling factors were examined in bivariate and logistic regression analyses. RESULTS: Twenty-two percent of respondents used services in the past year. Having concurrent disorders (comorbidity), troubled relationships with others, and dysfunction in main activity, feeling comfortable talking to a professional about mental health problems, being older and an urban resident, not working or being in school, and having a biological parent with an alcohol or drug problem were all associated with service use. CONCLUSIONS: The results suggest that individual determinants, such as severity of illness, disability, attitudes, and predisposing or enabling variables, all have a role in predicting service use among individuals in the general population who suffer from alcohol and other drug disorders.

Binge eating and substance use among male and female adolescents.

OBJECTIVE: This study examines the relationship between binge eating and substance use behaviors and attitudes in adolescents and explores gender differences and mental health correlates. METHOD: The data are derived from the 1997 Ontario Student Drug Use Survey of public and Catholic school students. A weighted sample of 1,031 girls and 888 boys was categorized as nonbingers, past bingers, and noncompensating or compensating binge eaters. RESULTS: Binge eaters, particularly those who compensated, were more likely to use all types of substances, particularly cannabis and drugs other than tobacco and alcohol. Binge eating was associated with more problematic and heavier substance use and with lowered self-esteem and more depression. Female bingers were more likely to report compensatory behaviors than male students but gender differences in the relationship between binge eating and substance use were few. DISCUSSION: Adolescent binge eaters who engage in compensatory behaviors may be an appropriate target group for preventive programs in high schools.

Secretion of plasminogen activator by cultured rat endometrial stromal cells from uteri differentially sensitized for the decidual cell reaction.

Endometrial stromal cells from rat uteri differentially sensitized for the decidual cell reaction in vivo and which undergo differing degrees of decidualization in vitro were cultured and plasminogen activator (PA) in the medium determined. The cells were obtained by enzymatic dispersion from the uteri of ovariectomized, steroid-treated rats at the equivalent of day 4, 5, or 6 of pseudopregnancy or on day 5 from rats treated on day 4 with 0, 0.3, or 1.0 microgram estradiol (low, intermediate, or high dose of estradiol, respectively) and cultured for 24, 48, or 72 hr. For cells from day 4, 5, and 6 uteri cultured under control conditions, PA activity in the medium was greatest for day 5 cells, which were from uteri maximally sensitized for decidualization both in vivo and in vitro. By contrast, for cells from low-, intermediate-, and high-estradiol uteri, PA activity in the medium was greatest for the high-estradiol cells; these cells do not undergo decidualization in vivo or in vitro to the same extent as intermediate-estradiol cells. Indomethacin, an inhibitor of prostaglandin (PG) synthesis, reduced PGE2 accumulation to nondetectable amounts and for most cultures decreased PA activity in the medium, suggesting that endogenous PG production regulated in part PA secretion under control conditions. The addition of PGE2 with indomethacin increased PA activities above those under control conditions, but activities were still lower for day 4 and 6 cells compared with day 5 cells, and for low- and intermediate-estradiol cells compared with high-estradiol cells. This indicates that the differences in PA secretion are not explainable by differences in PGE2 production. Northern blot analysis of RNA from cells cultured for 72 hr under control conditions did not reveal significant differences in steady-state concentrations of mRNA for urokinase-type PA or plasminogen activator inhibitor 1, but those for tissue-type PA were lower in day 6 cells compared with day 4 and 5 cells. It is concluded that PA activity secreted by the cultured endometrial stromal cells, although controlled in part by the endocrine milieu to which they were exposed prior to culture, does not simulate decidualization in vitro and, therefore, that PA activity is not a marker for decidualization in vitro.

Tissue shrinkage with the holmium:yttrium aluminum garnet laser. A postoperative assessment of tissue length, stiffness, and structure.

The effect of laser energy on the length, stiffness, and structure of connective tissue was examined in a rabbit patellar tendon model. A holmium:yttrium-aluminum-garnet laser was used to deliver a calculated dose of laser energy (300 J/cm2) to one randomly selected patellar tendon in each of 13 adult New Zealand White rabbits. The contralateral patellar tendon was used as a control. Radiopaque markers were placed in the patella and tibial tuberosity to allow for patellar tendon length measurements (via standard lateral radiographs) before and after laser application and at 4 and 8 weeks. Limbs were not immobilized during the postoperative period. The tendons were harvested at 0 weeks (N = 7) and 8 weeks (N = 6) and evaluated for tensile, stiffness, cross-sectional area, histologic changes, and electron microscopic appearance. The results demonstrated significant tendon shrinkage (6.6% +/- 1.4%) after application of the calculated laser energy dose. However, tendon length had increased significantly beyond the immediate postlaser length at 4 weeks and beyond its original length by 8 weeks. At 8 weeks, the lased tendons were significantly less stiff with significantly greater cross-sectional areas than contralateral controls. There was generalized fibroblastic response throughout the entire lased tendon characterized by a marked increase in cellularity. There was also a change from the normal bimodal pattern of large- and small-diameter collagen fibers to a unimodal pattern with predominantly small-diameter fibers in the lased tendons. The tissue alterations seen in this study suggest that the biologic response of connective tissue to laser energy causes a further compromise in tissue integrity, beyond that attributed to the initial physical effects of the laser. These alterations must be taken into consideration when determining postoperative rehabilitation of laser-modified tissues.

Retention in substance abuse treatment. Role of psychiatric symptom severity.

The authors investigated the association between psychiatric symptom severity and subsequent treatment retention among substance abusers. The Symptom Check List-90-R was administered, after admission to an addiction treatment facility, to 308 male and 106 female clients with moderate-to-severe substance abuse problems. Mean scores on nine symptom and three summary scales were computed. Controlling for other sociodemographic and treatment variables, somatization was significantly associated with dropout from specialized outpatient and inpatient treatment programs. This study, however, suggests that psychopathologic symptom severity at admission has only limited utility in predicting subsequent treatment retention among substance abusers with overall moderate levels of psychological distress.

Temporal- and hormone-dependent changes in uterine sensitization for the decidual cell reaction and decidualization in vitro of rat endometrial stromal cells.

The ability of endometrial stromal cells from nonsensitized rat uteri to undergo decidualization in vitro was investigated. Cells were obtained by enzymatic dispersion from uteri of ovariectomized, steroid-treated rats at the equivalent of day 4, 5 or 6 of pseudopregnancy, or on day 5 from rats treated with 0, 0.3 or 1.0 microgram oestradiol (low, intermediate or high doses of oestradiol, respectively) on day 4, and cultured for 24, 48 or 72 h. Decidualization in vivo, as assessed by uterine mass 5 days after the unilateral intrauterine injection of 100 microliters sesame oil, was maximal for rats receiving the deciduogenic stimulus on day 5 and treated with the intermediate dose of oestradiol. Under control conditions in vitro, alkaline phosphatase (ALP) activity, the increase in ALP activity with time, and prostaglandin E2 (PGE2) accumulation in the medium were greatest for cells from maximally sensitized uteri. Indomethacin, an inhibitor of PG synthesis, reduced PGE2 accumulation to barely detectable amounts, and decreased ALP activity, especially in cells from maximally sensitized uteri, indicating that endogenous PG production contributed to the increase in ALP activity in these cells. The addition of PGE2 with indomethacin increased ALP activities. However, ALP activities were lower for cells derived from nonsensitized uteri when compared with cells from maximally sensitized uteri. These results suggest that endometrial stromal cells from nonsensitized uteri have a reduced capacity to undergo decidualization in vitro, and that this reduced capacity is not explained by differences in PGE2 production.

Regulation of plasminogen activator in rat endometrial stromal cells: the role of prostaglandin E2.

The rat endometrium undergoes decidualization, a tissue remodeling process, during embryo implantation. Plasminogen activator (PA), particularly the urokinase-type PA (uPA), has been implicated in tissue remodeling. The present study determined whether rat endometrial stromal cells secrete uPA during decidualization in vitro and, if so, whether the secretion is regulated by prostaglandins that are required in decidualization. Endometrial stromal cells were obtained from rats that had been treated with estrogen and progesterone to sensitize their uteri for decidualization, and the cells were cultured for up to 72 h in a serum-free medium. PA activity in the conditioned medium, as determined by a chromogenic assay, increased steadily during the 72-h culture period. PA secretion decreased when endogenous prostaglandin synthesis was inhibited by the addition of indomethacin to the cell cultures. The inhibitory effect of indomethacin on PA secretion was reversed by prostaglandin E2, and much less effectively by prostaglandin F2 alpha. PA activity in the medium was due primarily to uPA because 1) PA activity was inhibited by a uPA-specific inhibitor-amiloride-and by an anti-mouse uPA antibody, and 2) the predominant PA activity in the medium, as identified in zymography, had a molecular mass of approximately 40 kDa, similar to that reported for uPA. Northern blot analyses of RNA from the cultured cells demonstrated that the steady-state levels of mRNA for uPA, but not for tPA and plasminogen activator inhibitor-1, were decreased by indomethacin; this decrease was reversed by prostaglandin E2. Taken together, the data indicate that rat endometrial stromal cells secrete uPA during decidualization in vitro, and that prostaglandin E2 regulates uPA secretion by the decidualizing cells by directly increasing uPA gene transcription and/or stabilizing its transcripts. These findings may help to partially elucidate the mechanism of action of prostaglandin E2 in decidualization.

DSM-III-R alcohol abuse and dependence and psychiatric comorbidity in Ontario: results from the Mental Health Supplement to the Ontario Health Survey.

The lifetime prevalence of DSM-III-R alcohol abuse and alcohol dependence and associated patterns of psychiatric comorbidity in the Ontario population aged 15-64 years are estimated from a survey of a representative household sample using the University of Michigan Composite International Diagnostic Interview (UM-CIDI). More than half (55%) of all individuals with an alcohol disorder have a lifetime comorbid disorder and comorbidity is more common in women than in men with an alcohol disorder. The odds of having other drug disorders and antisocial personality disorder are very high in individuals with an alcohol disorder compared to those without. Alcohol dependents, but not alcohol abusers, have significantly increased odds of mood and anxiety disorders compared to individuals without an alcohol disorder. Sociodemographic risk profiles, alcohol use patterns and course differ for alcohol abusers/dependents with and without a comorbid disorder. Primary anxiety and drug disorders are risk factors for subsequent alcohol disorders.

Diagnosing comorbidity in substance abusers: a comparison of the test-retest reliability of two interviews.

This study examines the test-retest reliability of two interview schedules (computer- and clinician-administered) in diagnosing lifetime comorbidity in treated substance abusers. The Computerized Diagnostic Interview Schedule (C-DIS) and the Structured Clinical Interview for DSM-III-R (SCID) were both administered to 173 substance abusers after random assignment to one of two groups. Within 1 to 2 weeks, subjects in the first group repeated the C-DIS and subjects in the second group were reinterviewed by a different clinician, blind to the results of the initial SCID. Both instruments showed good to excellent reliability for DSM-III-R psychoactive substance use disorders with kappas ranging from .50 to .89 for individual disorders. However, the reliability of comorbid other mental disorders was substantially poorer on both instruments, particularly the SCID. C-DIS kappas ranged from -.05 for generalized anxiety to .70 for simple phobia. SCID kappas ranged from .31 for panic disorder to .83 for antisocial personality disorder. Anxiety disorders as a category, some phobic disorders, and antisocial personality disorder showed acceptable levels of test-retest reliability on both instruments. There was a trend for borderline or threshold cases to account for some of the disagreement on the C-DIS. Differences of opinion between clinicians on organicity accounted for some of the disagreements on panic disorder and major depression. The C-DIS, unlike the SCID, tended to diagnose more disorders at initial interview, perhaps a result of its tedious probe structure. Neither instrument should be administered only once to provide a reliable lifetime diagnostic profile of comorbidity in substance abusers.

Diagnosing comorbidity in substance abusers. Computer assessment and clinical validation.

This study compares DSM-III-R lifetime diagnoses assigned to a sample of substance abusers in treatment made by the Computerized Diagnostic Interview Schedule (C-DIS) with those made by clinicians on the basis of the Structured Clinical Interview for DSM-III-R (SCID) and patient chart information. A sample of 173 subjects were interviewed with the C-DIS and then by a clinician using the SCID. A second SCID was administered by a different clinician to 80 of the subjects 1 to 2 weeks later and consensus diagnoses were then made using all available information. With the exception of antisocial personality disorder and most psychoactive substance use disorders, the initial C-DIS showed poor diagnostic agreement with the initial SCID. As a potential screening instrument, the C-DIS did identify 30 of the 32 subjects with a consensus axis I (nondrug) disorder, but diagnosed twice as many positives as were confirmed by the consensus diagnoses. A negative C-DIS for comorbid disorders was confirmed in 9 out of 10 cases by clinicians.

The natural moon illusion: a multifactor angular account.

It is argued that the failure to explain the celestial illusion results from conceptual confusion about perceived size and from disregard of the observational evidence relating to the natural moon illusion. The evidence shows that the illusion consists of a perceived angular size enlargement of horizon objects, by a factor of about 1.5-2.0 in diameter in comparison with elevated objects. Most measurements of the illusion have been made in terms of angular size, although in some proposed explanations an illusion of linear size is assumed. The magnitude of the illusion varies, particularly with the detail of the horizon scene. The illusion can be explained as the sum of several factors that affect perceived angular size: size contrast, vergence commands and eye or head position, aerial perspective, and colour. The relative contributions of these factors are assessed.

Effect of prostaglandin E2 on rate of decidualization in rats.

Based on morphology, it has been suggested that prostaglandin E2 (PGE2) accelerates the process of endometrial stromal cell differentiation to decidual cells in the rat. The present study investigated this possibility, using changes in uterine weight and in endometrial alkaline phosphatase (ALP) activity as indicators of decidualization. Rats were ovariectomized and treated with one of two steroid protocols; the first was identical to that previously used for the study of morphology, the second a modified protocol which results in greater uterine sensitization for decidualization, producing larger amounts of decidual tissue, thereby making it easier to detect differences between treatments. On the day of uterine sensitization, rats within each treatment protocol were given a unilateral intrauterine infusion of phosphate-buffered saline (PBS) or PGE2 plus indomethacin, and killed 24, 48 or 72 h later. The time-courses for the increases in uterine weight and ALP activity in uterine horns infused with PBS or PGE2 plus indomethacin differed between steroid protocols, but within a protocol were statistically indistinguishable. The results do not support the hypothesis that PGE2 accelerates the process of decidualization but do provide additional support for the notion that PGE2 is a physiological rather than pharmacological mediator of decidualization.