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Biomedical subjects

J Yager

Publications and source records attributed to J Yager.

At least 19 recordsLinked to original sources
PubMed2001

Control of Drosophila perineurial glial growth by interacting neurotransmitter-mediated signaling pathways.

Drosophila peripheral nerves, similar structurally to the peripheral nerves of mammals, comprise a layer of axons and inner glia, surrounded by an outer perineurial glial layer. Although it is well established that intercellular communication occurs among cells within peripheral nerves, the signaling pathways used and the effects of this signaling on nerve structure and function remain incompletely understood. Here we demonstrate with genetic methods that the Drosophila peripheral nerve is a favorable system for the study of intercellular signaling. We show that growth of the perineurial glia is controlled by interactions among five genes: ine, which encodes a putative neurotransmitter transporter; eag, which encodes a potassium channel; push, which encodes a large, Zn(2+)-finger-containing protein; amn, which encodes a putative neuropeptide related to the pituitary adenylate cyclase activator peptide; and NF1, the Drosophila ortholog of the human gene responsible for type 1 neurofibromatosis. In other Drosophila systems, push and NF1 are required for signaling pathways mediated by Amn or the pituitary adenylate cyclase activator peptide. Our results support a model in which the Amn neuropeptide, acting through Push and NF1, inhibits perineurial glial growth, whereas the substrate neurotransmitter of Ine promotes perineurial glial growth. Defective intercellular signaling within peripheral nerves might underlie the formation of neurofibromas, the hallmark of neurofibromatosis.

Animals↗
PubMed2001

Cerebral sinovenous thrombosis in children.

BACKGROUND: Cerebral sinovenous thrombosis in children is a serious disorder, and information is needed about its prevention and treatment. METHODS: The Canadian Pediatric Ischemic Stroke Registry was initiated in 1992 at the 16 pediatric tertiary care centers in Canada. Children (newborn to 18 years of age) with symptoms and radiographic confirmation of sinovenous thrombosis were included. RESULTS: During the first six years of the registry, 160 consecutive children with sinovenous thrombosis were enrolled, and the incidence of the disorder was 0.67 cases per 100,000 children per year. Neonates were most commonly affected. Fifty-eight percent of the children had seizures, 76 percent had diffuse neurologic signs, and 42 percent had focal neurologic signs. Risk factors included head and neck disorders (in 29 percent), acute systemic illnesses (in 54 percent), chronic systemic diseases (in 36 percent), and prothrombotic states (in 41 percent). Venous infarcts occurred in 41 percent of the children. Fifty-three percent of the children received antithrombotic agents. Neurologic deficits were present in 38 percent of the children, and 8 percent died; half the deaths were due to sinovenous thrombosis. Predictors of adverse neurologic outcomes were seizures at presentation and venous infarcts. CONCLUSIONS: Sinovenous thrombosis in children affects primarily neonates and results in neurologic impairment or death in approximately half the cases. The occurrence of venous infarcts or seizures portends a poor outcome.

Adolescent↗
PubMed2001

E-mail as a therapeutic adjunct in the outpatient treatment of anorexia nervosa: Illustrative case material and discussion of the issues.

OBJECTIVE: To explore using adjunctive e-mail in treating anorexia nervosa. METHOD: Four treatment plans were supplemented by obligatory e-mail emphasizing patients' reports of specific eating-related behaviors. Office visits occurred weekly to once every few months. E-mail contact occurred once to several times per week. Patients also saw other providers. RESULTS: All patients have shown good clinical improvement. Patients provided their assessments of contributions made by the use of e-mail and generally found it to be helpful. DISCUSSION: E-mail has had excellent patient acceptability and adherence. Benefits have been attributed to increased therapeutic contact, "talking" on demand, and having to frequently confront one's integrity, honesty, and eating behaviors. Little clinician time is needed for reading and responding to e-mails. Informed consent and confidentiality issues must be carefully addressed. Controlled trials are warranted to further evaluate the roles that adjunctive e-mail may play in clinical research and practice.

Adolescent↗
PubMed2001

Implementing the revised American Psychiatric Association practice guideline for the treatment of patients with eating disorder.

Practice guidelines aspire to be authoritative statements regarding the state of the art in quality care for various clinical problems. The American Medical Association Partnership has set forth stringent parameters for guideline development by professional organizations, and these have been followed by the American Psychiatric Association in creating its practice guidelines for the treatment of patients with eating disorders. The revised edition, published in January 2000, benefitted from extensive input from a wide array of psychiatrists, psychologists, pediatricians, and other recognized experts who blended together available evidence-based practice with a considerable amount of clinical experience and consensus. These guidelines are useful for practitioners, students, and health-resource managers. Future research will continue to lead to constant upgrades.

Feeding and Eating Disorders↗
PubMed2000

Development and validation of the Parental Intrusiveness Rating Scale among bulimic and comparison women.

OBJECTIVE: Based on hypotheses generated during clinical interviews with 80 women with a lifetime history of bulimia nervosa (BN), we designed an instrument for assessing the extent to which women with BN report parental intrusiveness and breakdown of appropriate role boundaries during their adolescent development. METHOD: Through an iterative process of item generation and scale administration, the Parental Intrusiveness Rating Scale (PIRS), consisting of 20 maternal items and 20 paternal items, was developed. Maternal subscales include Invasion of Privacy, Jealousy and Competition, and Overconcern with the Daughter's Eating, Weight, and Shape. Paternal subscales include Invasion of Privacy, Seductiveness, and Overconcern with the Daughter's Eating, Weight, and Shape. We validated the instrument using a subset of the above BN and comparison women (ns = 55 and 33, respectively), as well as an independent sample of women with BN and college comparison subjects (ns = 31 and 540, respectively). RESULTS: Parental intrusiveness scores were significantly positively correlated with disturbed relationships in the family of origin of our initial cohort. Reliability analyses, both test-retest and item-scale correlations, revealed adequate to strong statistical associations in the combined sample. CONCLUSION: The PIRS promises to enrich our understanding of problematic parental behaviors among women who develop BN and allows us to broaden the conceptualization of familial risk factors for this disorder.

Adolescent↗
PubMed2000

Parental intrusiveness in adolescence recalled by women with a history of bulimia nervosa and comparison women.

OBJECTIVE: To learn if women with a lifetime history of bulimia nervosa (BN) report more intrusive parental behavior during adolescence than their nonclinical peers, and to provide further validation of the Parental Intrusiveness Rating Scale (PIRS). METHOD: We administered the PIRS to 86 women with a lifetime history of BN and 573 comparison subjects and examined between-group differences. RESULTS: Relative to the comparison group, lifetime BN subjects reported higher levels of parental intrusiveness, specifically maternal invasion of privacy, maternal jealousy and competition, paternal seductiveness, and maternal and paternal overconcern with the daughter's eating, weight, and shape. There were no between-group differences in paternal invasion of privacy. In exploratory analyses with the comparison sample, Caucasian women reported greater maternal jealousy and competition than Asian American/Pacific Islander women, but there were no other differences. CONCLUSION: These results support clinical observations of high levels of parental intrusiveness in the adolescent experiences of women who develop BN. Nonclinical women of diverse ethnic backgrounds report largely equivalent experiences.

Adolescent↗
PubMed1999

Social support, social adjustment, and recovery status in bulimia nervosa.

OBJECTIVE: To examine recovery status in bulimia nervosa (BN) and its relation to social support and social adjustment. METHOD: Using a cross-sectional design, we administered the modified Social Support Questionnaire and the Social Adjustment Scale-Self-Report (SAS-SR) to 40 women, each of whom was actively bulimic (ABN), was in remission from BN (RBN), or had no history of eating disturbance (comparison). RESULTS: In terms of social support, relative to RBN and comparison subjects, the ABN group had significantly fewer persons in their friendship and kinship networks available to provide emotional support, although the groups were equivalent in number of persons available to provide things and advice. Relative to the comparison group, both bulimic groups were significantly dissatisfied with the quality of emotional support provided by relatives. On the SAS-SR, women in the ABN group displayed the poorest overall social functioning. The RBN group was functioning significantly better than the ABN group, but significantly more poorly than the comparison group. DISCUSSION: Our results suggest that the social functioning of RBN women lies between ABN women and non-eating-disordered women, indicating both gains relative to the active phase and residual deficits.

Adult↗
PubMed1997

Intercomparison of analytical methods for arsenic speciation in human urine.

An intercomparison exercise was conducted for the quantification of arsenic species in spiked human urine. The primary objective of the exercise was to determine the variance among laboratories in the analysis of arsenic species such as inorganic As (As+3 and As+5), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA). Laboratories that participated had previous experience with arsenic speciation analysis. The results of this interlaboratory comparison are encouraging. There is relatively good agreement on the concentrations of these arsenic species in urine at concentrations that are relevant to research on the metabolism of arsenic in humans and other mammals. Both the accuracy and precision are relatively poor for arsenic concentrations of less than about 5 micrograms/l.

Adult↗
PubMed1997

Preparing psychiatric residents for managed care. Values, proficiencies, curriculum, and implications for psychotherapy training.

As managed care psychiatric service systems become increasingly prominent in academic centers and the larger world of psychiatric practice, residency programs find themselves having to adapt to the value systems and training paradigms necessary for preparing house staff to deal with these systems. Many of the values and some of the necessary proficiencies differ considerably from those of traditional fee-for-service psychiatric practice. This article delineates the value systems under which managed care systems operate, the clinical proficiencies that will be needed by psychiatrists practicing in such settings, the experiential and didactic curriculum necessary to prepare today's psychiatric residents for adapting to managed care-oriented practices, and the implications of these changes for psychotherapy education and training.

Curriculum↗
PubMed1996

Engineering of a sugar-derivatized porous network for hepatocyte culture.

Many tissue engineering applications require a scaffold or template conducive to cell attachment and maintenance of functions. It may also be advantageous in some cases for these scaffolds to have a controlled porous architecture to facilitate cellular or tissue ingrowth. In this study, we have engineered a porous carbohydrate-derivatized substrate for hepatocyte culture. Polystyrene foams, with pore sizes up to 100 microns, fabricated by phase separation from a homogeneous naphthalene solution, were derivatized with lactose and heparin, both of which are known to promote rat hepatocyte attachment and maintenance of its differentiated functions. Rat hepatocytes cultured on these derivatized foams exhibited a rounded cellular morphology with many microvilli evident on the surface of the cells. The hepatocytes showed an increase in albumin secretion for the first 3 days of culture in a defined, serum-free medium, and dropped back to initial levels by the end of 7 days. The production of cytochrome P450-dependent hydroxytestosterone metabolites were also measured. Two testosterone metabolites were maintained and five others were present but decreased over a culture period of 1 week. These carbohydrate-derivatized porous substrates may be useful for large-scale culture of hepatocytes, toxicology screening and for use in a liver assist device.

Animals↗
PubMed1996

Histories of childhood trauma and complex post-traumatic sequelae in women with eating disorders.

The profound self-destructiveness and tenacity of eating disorders found among women abused and neglected in childhood become comprehensible when understood within a complex posttraumatic conceptualization as desperate attempts to regulate overwhelming affective states and construct a coherent sense of self and system of meaning. Trauma leads to the predictable consequences of dysregulation of the arousal system, avoidance, and constriction of affect; coherence of self and world are shattered. Abused patients' childhood experiences teach them that to need is to expose oneself to the pain of abandonment and betrayal at the hands of individuals responsible for their care. Consequently, needs-psychological, physical, and spiritual-come to be perceived as dangerous, and human relationships are simultaneously yearned for and feared. Robbed of the opportunity to develop a cohesive self and a coherent system of meaning and faith to sustain from within, the traumatized eating-disorder patient turns to the culture to tell her who to be and how to live; she learns that to conquer rather than satisfy needs and to be "in control" (an internal state of equanimity manifested externally in a thin body) will bring meaning and purpose. Binge eating, purging, and starving become apt metaphors for the boundless hunger, the wish to fulfill needs together with the wish to rid oneself forever of need, the desire to "purify" the damaged psychic and physical self, and the hope of restoring meaning. The treatment of the traumatized eating disorder patient is complex. Individual therapy provides the opportunity for intensive relational work that begins to restore faith in human connection and that provides a "safe base" from which to examine the trauma and separate past from present. Therapy groups for eating-disordered women and trauma survivors provide relief from isolation, valuable perspectives from others who have "been there," and the opportunity to contribute to others' healing as one heals. Ultimately, these patients must be willing to leave the world of obsession with food and weight, which guarantees safety from interpersonal hurt while it simultaneously guarantees that hope will not be restored. Though reconnecting with humanity carries the risk of further pain, it opens up the opportunity for connection, healing, and growth.

Feeding and Eating Disorders↗