Biomedical subjects

C S Carter

Publications and source records attributed to C S Carter.

At least 91 records · Page 5Linked to original sources

PubMed1996

The biobehavioral consequences of psychogenic stress in a small, social primate (Callithrix jacchus jacchus).

The biobehavioral consequences of psychogenic stress were examined using neuroendocrine and ethological methods in a captive colony of common marmosets (Callithrix jacchus jacchus). Specifically, hypothalamic-pituitary-adrenal (HPA) axis reactivity was evaluated as a function of gender and social status in four consecutive social environments [(1) stable heterosexual pairs; (2) isolation; (3) unstable peer groups; and (4) stable peer groups], by measuring both basal plasma cortisol, adrenocorticotropic hormone (ACTH) and beta-endorphin concentrations and responsiveness of these hormones to dexamethasone, ovine corticotropin-releasing hormone (oCRH), and ACTH1-24. Socially stressful conditions, such as isolation and peer group formation, were associated with increased HPA axis function and behavioral arousal, and individual profiles were related to gender and social status. Hormonal levels prior to group formation predicted subsequent status in peer groups. Basal morning concentrations of plasma cortisol, as well as cortisol responsiveness to dexamethasone suppression, were sensitive indices of HPA axis arousal during periods of social stress. The context-dependent development of hormonal and behavioral profiles, reminiscent of depression and/or anorexia nervosa, suggests that the common marmoset may be a useful model of psychiatric hypercortisolism.

Adrenocorticotropic Hormone↗

PubMed1996

Perceptual and attentional asymmetries in schizophrenia: further evidence for a left hemisphere deficit.

Increasing evidence suggests the presence of a lateralizing attentional deficit in schizophrenia. In the present study, 23 unmedicated patients with schizophrenia (mean age = 32.1 years) and 14 age- and sex-matched normal subjects were studied with the Global/Local Task to provide converging evidence for the presence of a left-hemisphere-associated attentional deficit in schizophrenia. This task is sensitive to the integrity of mechanisms involved in discriminating local and global elements of stimuli. Previous research has linked the discrimination of local targets to left hemispheric processes and the discrimination of global targets to right hemispheric processes. As predicted, patients were impaired in the detection of local level targets, consistent with a left hemispheric deficit. The degree of impairment correlated with the patient's level of auditory hallucinations. These results are consistent with previous studies showing an asymmetrical attentional deficit in schizophrenia and left hemispheric dysfunction. The correlation between this deficit and auditory hallucinations is consistent with a hypothesized relationship between this symptom in schizophrenia and left temporal pathology.

Adult↗

PubMed1996

Perinatal steroid treatments alter alloparental and affiliative behavior in prairie voles.

This experiment was designed to examine the hypothesis that perinatal manipulation of gonadal or adrenal steroids can alter the subsequent expression of juvenile parental (alloparenting) and affiliative behavior in prairie voles (Microtus ochrogaster). Corticosterone (PRECORT), testosterone (PRE-TP), or oil injections (PRESES) were given on Prenatal Days 12-20 or on Postnatal Days 1-6 (CORT6, TP6, or SES6, respectively). Alloparenting was reduced significantly in females in the CORT6 group and in males in the TP6 group. Sibling affiliative preferences were increased significantly in PRE-TP females and stranger preferences were increased in TP6 and CORT6 females. The results suggest timing is a critical factor determining whether hormones have a facilitative or inhibitory effect on alloparental and affiliative behavior in prairie voles. In this species, corticosterone and testosterone have similar organizational effects on affiliative behavior in females. Alloparental behavior is inhibited by postnatal corticosterone administration in females and by postnatal testosterone administration in males, whereas prenatal steroid administration had no significant effect on alloparenting in either gender.

Animals↗

PubMed1995

Adrenocorticoid hormones and the development and expression of mammalian monogamy.

Based on research with prairie voles, we hypothesize that the unusual patterns of reproduction and social behavior associated with mammalian monogamy may arise as a consequence of normal developmental exposure to high levels of glucocorticoids and/or other hormones of the HPA axis. Increased HPA activity could functionally inhibit some of the masculinizing processes expected during the perinatal period. We hypothesize that the unique behavioral, physiological, and anatomical changes associated with monogamy may reflect the adaptive consequences of reduced exposure to the masculinizing actions of HPG hormones, such as testosterone. Reproductively naive, unpaired adult prairie voles also show unusual patterns of adrenal activity, including a marked decline in corticosterone levels within minutes following exposure to novel animals of the opposite sex. In females, this decline in corticosterone may contribute to pair bonding, since corticosterone injections inhibit, and adrenalectomy is associated with a facilitation of pair bond formation. In males, corticosterone injections facilitate pair bonding and adrenalectomy has the opposite effect. In animals from established social pairs corticosterone levels also fluctuate according to the social environment of the animal; the absence of a familiar partner is associated with increased corticosterone secretion, and in the presence of the familiar partner corticosterone levels tend to decline. Prairie voles may offer a valuable source of information regarding the behavioral, anatomical, and physiological consequences of long-term and short-term exposure to high levels of adrenal activity in the absence of pathology.

Adrenal Cortex Hormones↗

PubMed1995

T lymphocyte-directed gene therapy for ADA- SCID: initial trial results after 4 years.

In 1990, a clinical trial was started using retroviral-mediated transfer of the adenosine deaminase (ADA) gene into the T cells of two children with severe combined immunodeficiency (ADA- SCID). The number of blood T cells normalized as did many cellular and humoral immune responses. Gene treatment ended after 2 years, but integrated vector and ADA gene expression in T cells persisted. Although many components remain to be perfected, it is concluded here that gene therapy can be a safe and effective addition to treatment for some patients with this severe immunodeficiency disease.

Adenosine Deaminase↗

PubMed1995

Modulation of pair bonding in female prairie voles (Microtus ochrogaster) by corticosterone.

Glucocorticoid levels in animals may respond to and influence the development of social attachments. This hypothesis was tested in prairie voles (Microtus ochrogaster), monogamous rodents that form long-term heterosexual pair bonds. In socially naive female prairie voles, cohabitation with an unfamiliar male resulted in a dramatic decline in serum corticosterone levels. When corticosterone levels were reduced via adrenalectomy, females developed partner preferences after 1 h of cohabitation, while sham-operated and untreated females required 3 h or more of nonsexual cohabitation to establish a partner preference. In adrenalectomized and intact females, exogenous injections of corticosterone, given prior to social exposure, prevented the development of preferences for the cohabitating male. Although corticosterone inhibited the development of partner preferences, it did not interfere with the expression of previously established social preferences. These results suggest that social stimuli can modulate adrenal activity and that adrenal activity, in turn, is capable of influencing the formation of adult social preferences in female prairie voles. The involvement of the adrenal axis in the formation of partner preferences and the subsequent development of pair bonds provides a mechanism through which environmental and social factors may influence social organization in this species.

Adrenalectomy↗

PubMed1995

Asymmetrical visual-spatial attentional performance in ADHD: evidence for a right hemispheric deficit.

This study was designed to confirm the presence of a lateralizing deficit in visual-spatial attention in children with ADHD, to further characterize the nature of this deficit and to specify the likely hemispheric locus of dysfunction. Two versions of the covert orienting of attention procedure which evaluated separately endogenous and exogenous cuing effects were administered to 20 unmedicated children aged 9-12 with ADHD and 20 matched controls. Both groups also underwent thorough psychiatric assessment and testing using the TOVA and the Wisconsin Card Sorting Task (WCST). Children with ADHD showed an asymmetrical performance deficit characterized by a loss of costs on controlled (endogenous) attentional orienting to invalidly cured left visual field targets. The degree of cost asymmetry correlated negatively with the number of categories sorted on the WCST. It was concluded that unmedicated children with ADHD show an asymmetrical performance deficit on the covert orienting procedure characterized by a disruption of right hemispheric attentional mechanisms. This deficit may be related to diminished right hemispheric frontal-striatal catecholamine activity.

Attention↗

PubMed1995

Abnormal processing of irrelevant information in attention deficit hyperactivity disorder.

The presence of a selective attention deficit in children with attention deficit hyperactivity disorder (ADHD) was investigated by administering a trial-by-trial version of the Stroop Color-Naming Task to children, aged 9-12, with ADHD (n = 19) and age-matched normal control children (n = 19). Performance was evaluated on both interference and facilitation components of the task. On the standard version of the task, with equal numbers of color words and neutral words, children with ADHD showed increased Stroop interference (prolongation of color-naming times by color-incongruent stimuli) but normal amounts of facilitation (speeding of color naming by color-congruent stimuli). This finding suggests that children with ADHD show increased disruption of color-naming performance by task-irrelevant information, probably secondary to decreased attentional control over the interference process. In contrast to findings of studies in adults, both groups of children failed to use an attentional strategy to reduce interference when they were administered blocks of trials that varied their expectancy for color word trials. This precluded a direct test of the diminished control hypothesis. There were no significant correlations between abnormal Stroop performance and impairment on the Continuous Performance Test or the Wisconsin Card Sorting Test or measures of IQ or reading performance. The implications of these findings for our understanding of information-processing deficits in children with ADHD and of the neurobiological underpinnings of these deficits are discussed.

Attention↗

PubMed1995

Neonatal medial prefrontal lesions and recovery of spatial delayed alternation in the rat: effects of delay interval.

We have previously shown that rats given medial prefrontal lesions on postnatal Day 10 show a performance deficit on spatial delayed alternation (2-s delay) when tested between Days 19 and 23, but show recovery of function by Days 27-33 (Freeman & Stanton, 1992). The present study attempted to (a) examine the effects of extending the delay interval from 2 s to 15 or 45 s on the ontogeny of spatial delayed alternation; and (b) determine whether these longer delays would alter the ontogenetic profile of recovery from medial prefrontal damage. Animals were given medial prefrontal lesions (mPFC) or sham surgery on Day 10. They received acquisition training on delayed alternation with a 2-s delay on Day 21 or Day 28, followed by "probe" tests at delays of 15 and 45 s on the following day (Day 22 or Day 29). On Days 21-22 there was an overall effect of lesion at the 2-, 15-, and 45-s delay intervals indicating an early deficit. However, on Days 28-29 there was no effect of lesion at the end of acquisition or at the 15- or 45-s delay intervals. Recovery of memory function by mPFC animals on this task appears to occur during the weanling period regardless of delay interval.

Aging↗

PubMed1995

Ontogeny of eyeblink conditioning in the rat: auditory frequency and discrimination learning effects.

The present study sought to determine whether acoustic properties of the auditory conditioned stimulus (CS) or the use of a discrimination learning procedure would alter the emergence of eyeblink conditioning between postnatal Days 17 and 24 (Days 17-24) in the rat. In Experiment 1, we employed a 3 x 2 x 2 factorial design, involving pitch of the auditory CS (2.8, 5.0, and 9.0 kHz), training condition (paired vs. unpaired), and age (Days 17 or 24). Associative learning was evident at all tone frequencies on Day 24, but increased across frequencies on Day 17, although large age differences in conditioning remained at all tone frequencies. In Experiment 2, rat pups were trained to discriminate 2.8 versus 9.0-kHz tones on Day 17 or Day 24. Eyeblink conditioning increased with tone frequency on Day 24 but discriminative conditioning failed to appear on Day 17. These findings are discussed in relation to the role of auditory system maturation in the ontogeny of eyeblink conditioning.

Acoustic Stimulation↗

PubMed1995

Interference and facilitation effects during selective attention: an H215O PET study of Stroop task performance.

To investigate the functional anatomy of interference and facilitation during selective attention, we studied 15 normal subjects using the H215O positron emission tomography technique and a computer presented single-trial Stroop task for cognitive activation. Increases in regional cerebral blood flow (rCBF) were observed in a network of structures that have been previously associated with selective attention, including the anterior cingulate gyrus, the frontal polar cortex, the inferior parietal lobule, and the thalamus, as well as the lingual gyrus. Furthermore rCBF decreases (compared to control states) were observed in lateral extra-striate cortex. rCBF changes in prefrontal and extra-striate regions varied with differences in the need to modulate the influence of word and color information while subjects responded to either incongruent or congruent Stroop stimuli. These results indicate the utility of Stroop procedures for investigating the functional anatomy of selective attention. Given recent interest regarding the role of the anterior cingulate gyrus in the pathophysiology of neuropsychiatric disorders, our results also suggest that the Stroop task can serve as a reliable neurobehavioral probe for this region. The significance of these results for understanding processing mechanisms underlying selective attention is discussed within the framework of a parallel distributed processing model of Stroop task performance.

Adult↗

PubMed1995

Physiological substrates of mammalian monogamy: the prairie vole model.

Prairie voles (Microtus ochrogaster) are described here as a model system in which it is possible to examine, within the context of natural history, the proximate processes regulating the social and reproductive behaviors that characterize a monogamous social system. Neuropeptides, including oxytocin and vasopressin, and the adrenal glucocorticoid, corticosterone, have been implicated in the neural regulation of partner preferences, and in the male, vasopressin has been implicated in the induction of selective aggression toward strangers. We hypothesize here that interactions among oxytocin, vasopressin and glucocorticoids could provide substrates for dynamic changes in social and agonistic behaviors, including those required in the development and expression of monogamy. Results from research with voles suggest that the behaviors characteristics of monogamy, including social attachments and biparental care, may be modified by hormones during development and may be regulated by different mechanisms in males and females.

Animals↗

PubMed1995

Early cerebellar lesions impair eyeblink conditioning in developing rats: differential effects of unilateral lesions on postnatal day 10 or 20.

Experiment 1 demonstrated that the ipsilateral cerebellar hemisphere is essential for the acquisition of eyeblink conditioning in infant rats and that cerebellar lesions given on Postnatal Day 10 (PND10) produced deficits in eyeblink conditioning when given to either hemisphere. For both hemispheres, lesions that were restricted to the cerebellar cortex produced less severe deficits than lesions that included the deep nuclei. Experiment 2 showed that the age at which the cerebellar lesions occurred determined whether damage to the contralateral cerebellar hemisphere impaired conditioning. Lesions of either the ipsilateral or contralateral hemisphere that included the deep nuclei disrupted eyeblink conditioning when given on PND10. In contrast, when lesions were given on PND20, ipsilateral lesions that included the deep nuclei abolished conditioning, while the same lesion given to the contralateral hemisphere had no effect.

Aging↗

PubMed1995

Helper T cells infiltrating human renal cell carcinomas have the phenotype of activated memory-like T lymphocytes.

Human renal cell carcinomas are characterized by an inflammatory infiltrate containing many T lymphocytes. Attempts to grow T cells from such tumors by culture in interleukin (IL)-2 have yielded heterogeneous populations of cells with functional characteristics typical of lymphokine-activated killer cells obtained by similar culture of cells from peripheral blood mononuclear cells. We examined a panel of surface markers expressed on T lymphocytes to determine if the CD4+ T cells infiltrating human renal cell carcinomas are different from those in peripheral blood mononuclear cells. By flow cytometry analysis the CD4+ T cells in a panel of freshly digested human renal cell carcinoma primary and metastatic tumors expressed the activation markers CD69 and HLA-DR and manifested an increase in CD45RO and a reciprocal decrease in CD45RA expression as compared with peripheral blood CD4+ T cells. This suggests that CD4+ T cells infiltrating renal cell carcinomas are activated and have encountered antigen. However, the expression of the IL-2R alpha chain (CD25) was not different in tumor-infiltrating CD4+ T cells and peripheral blood CD4+ T cells, suggesting that T cells infiltrating human renal cell carcinomas may have a block in proliferative capacity. The general failure of cultured tumor-infiltrating lymphocyte (TIL) from renal cell carcinoma to demonstrate tumor-specific reactivity may be due to the failure of such cells to grow in IL-2.

CD4-Positive T-Lymphocytes↗

PubMed1995

Suppression of hypothalmic-pituitary-adrenal axis responses to stress in lactating women.

In the rat, lactation suppresses a variety of physiological responses to stress. We investigated whether stress-responsive neurohormonal systems are also restrained during breast feeding in humans. We chose treadmill exercise as a stressor because this stimulus produces an exercise intensity-dependent activation of the hypothalamic-pituitary-adrenal axis and the sympathomedullary system that is independent of differences in physical conditioning among subjects. Ten lactating and ten nonlactating women who were between 7 and 18 weeks postpartum performed 20 min of graded treadmill exercise. The final 5 min of exercise was set to elicit 90% of the maximal oxygen uptake of each subject. Plasma ACTH, cortisol, and glucose responses to exercise were significantly attenuated in lactating women (P < 0.001, P < 0.05, and P < 0.001, respectively). Basal norepinephrine levels were also reduced in lactating women (P < 0.05). These results indicate that stress-responsive neurohormonal systems are restrained in lactating women.

Adrenocorticotropic Hormone↗

PubMed1995

Malignant fibrous histiocytoma of the larynx: case report and literature review.

Malignant fibrous histiocytoma of the larynx is a very rare neoplasm. This article reports the case of a subglottic malignant fibrous histiocytoma in a 38-year-old male treated by wide excision and radiotherapy. A literature search reveals this to be the 22nd case reported. Clinicopathologic features are discussed. The treatment of choice is wide surgical excision with consideration of adjunctive chemotherapy. Radiation therapy is probably of little benefit.

Adult↗

PubMed1995

Adinazolam-SR in panic disorder with agoraphobia: relationship of daily dose to efficacy.

BACKGROUND: We report the results from a multicenter, double-blind, randomized, fixed-dose study designed to evaluate the relationship between daily dose and efficacy of adinazolam-SR in patients with panic disorder with agoraphobia. METHOD: Patients (N = 315) were randomized to one of four treatment groups (placebo, N = 83; 30-mg group, N = 79; 60-mg group, N = 81; and 90-mg group, N = 72) and then treated twice daily for 4 weeks. All treatment groups were comparable demographically. Primary efficacy measures included total number of panic attacks, global improvement score using the Clinical Global Impressions (CGI) scale, phobic anxiety dimension of the Symptom Checklist-90 phobic cluster, overall phobia state using the Phobia Scale, and severity of illness on the CGI. RESULTS: The 60- and 90-mg/day adinazolam-SR treatment groups showed superior results when compared with the placebo group at Week 4 while the 30-mg group did not. Treatment with adinazolam-SR was well tolerated, with sedation the only treatment-emergent symptom that occurred more frequently in patients treated with adinazolam-SR than placebo. CONCLUSION: These results suggest that adinazolam-SR at doses of 60-mg/day or greater administered twice daily is a safe and effective treatment in selected patients with panic disorder with agoraphobia.

Adolescent↗

PubMed1995

Lack of sensitivity of indium-111 mixed leukocyte scans for active disease in Takayasu's arteritis.

OBJECTIVE: Currently, a reliable, noninvasive means of detecting the active vasculitic lesions of Takayasu's arteritis does not exist. Based on the cellular infiltrates seen in active lesions, we postulated that indium-111 labelled mixed leukocytes could be used to scintigraphically detect sites of active vasculitis. METHODS: Fifteen In-111 mixed leukocyte scans were performed in 10 patients with Takayasu's arteritis and correlated with clinical, laboratory, and radiographic findings. Patients had either active, stable/smoldering, or inactive disease at the time when 8, 4, and 3 scans were performed, respectively. RESULTS: Two of the 8 scans performed in patients with active disease were positive for increased vessel uptake (sensitivity = 25%). All other scans were interpreted as negative for active arteritis. CONCLUSION: We conclude that In-111 mixed leukocyte scans have a low sensitivity for detection of active Takayasu's arteritis.

Adult↗