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Biomedical subjects

C A Foster

Publications and source records attributed to C A Foster.

At least 19 recordsLinked to original sources
PubMed2006

Barré-Lieou syndrome and the problem of the obsolete eponym.

BACKGROUND: Eponym lists in major sources can give an aura of legitimacy to discredited diagnoses, as exemplified by the case of Barré-Lieou syndrome, a 'rare' vestibular disorder. METHODS: A literature review for information on the posterior cervical syndrome of Barré-Lieou. RESULTS: Barré-Lieou syndrome includes very common symptoms--tinnitus, dizziness, and head or neck pain--attributed to ischaemia caused by cervical sympathetic nerve compression. Its original description brings together many unrelated disorders, and its causative mechanism has been discredited. However, it appears credulously in a number of eponym lists, and references to the syndrome are steadily increasing on the internet in general and on alternative medicine and legal profession websites in particular. CONCLUSION: By inclusion in eponym lists, without a disclaimer, a syndrome can be given legitimacy before the general public. A syndrome, such as Barré-Lieou syndrome, that is useless to the medical profession can unfortunately prove to be very useful for litigants and disability claimants.

Cerebrovascular Disorders↗
PubMed2000

Synthesis and evaluation of aza HUN-7293.

The aza analogue of the cyclic heptadepsipeptide HUN-7293 (1), which is a potent naturally occurring inhibitor of inducible cell adhesion molecule expression, and its C2(3) (MLEU3 C2) epimer were prepared via solution-phase synthesis. Biological evaluations of these two compounds as inhibitors of cell adhesion molecules expression are detailed.

Cell Adhesion↗
PubMed1999

Commitment, pro-relationship behavior, and trust in close relationships.

The present work advances and tests an interdependence-based model of the associations among commitment, pro-relationship behavior, and trust. Findings from two longitudinal studies revealed good support for model predictions. Commitment-inspired acts such as accommodation and willingness to sacrifice provide diagnostic information regarding a partner's pro-relationship motives. Individuals come to trust their partners when they perceive that their partners have enacted pro-relationship behaviors, departing from their direct self-interest for the good of the relationship. The results of mediation analyses are consistent with a model of mutual cyclical growth in which (a) dependence promotes strong commitment, (b) commitment promotes pro-relationship acts, (c) pro-relationship acts are perceived by the partner, (d) the perception of pro-relationship acts enhances the partner's trust, and (e) trust increases the partner's willingness to become dependent on the relationship. Auxiliary analyses revealed that self-reported attachment style does not account for substantial variance beyond the features of interdependence that form the basis for the present model.

Adult↗
PubMed1999

Immobilization of goitred gazelles (Gazella subgutterosa) and Arabian mountain gazelles (Gazella gazella) with xylazine-ketamine.

Xylazine combined with ketamine successfully immobilized free-ranging and captive goitred gazelles (Gazella subgutterosa) and Arabian mountain gazelles (Gazella gazella). One hundred thirty immobilizations were performed on 58 individuals. When administered i.m. via dart to free-ranging gazelles, xylazine (125 mg/ml) combined with ketamine (100 mg/ml) produced smooth induction and recovery. Mountain gazelles required higher dosages (11.7-15.2 mg/kg xylazine and 9.3-12.2 mg/kg ketamine) than goitred gazelles (6.8-7.4 mg/kg xylazine and 5.4-5.9 mg/kg ketamine). For manually restrained captive gazelles of both species, i.v. xylazine (11 mg/ml) combined with i.v. ketamine (44 mg/ml) immobilized the gazelles at considerably lower doses (0.4-1.0 mg/kg xylazine and 1.4-3.9 mg/kg ketamine). These anesthetic combinations are useful alternatives to ultrapotent narcotics in these gazelle species.

Adrenergic alpha-Agonists↗
PubMed1997

Detection of serologic neutralizing antibodies against HPV-11 in patients with condyloma acuminata and cervical dysplasia using an in vitro assay.

This study was designed to investigate if neutralizing antibodies against HPV-11 are detectable in the serum of patients with condyloma acuminata (CA) or cervical intraepithelial neoplasia (CIN) using an in vitro infectivity assay for HPV-11. Purified HPV-11 virions were extracted from xenografted condyloma tissues implanted into athymic mice and used to infect cultured neonatal human foreskin keratinocytes (HFK) and an immortalized adult skin cell line (HaCaT). The presence of HPV-11-specific E1--E4 mRNA as detected by reverse transcriptase-polymerase chain reaction was indicative of early infection. Sera previously characterized for reactivity to HPV-11 and HPV-11 VLP (virus-like particles) by ELISA were tested for the ability to prevent HPV-11 in vitro infectivity. Neutralizing antibodies against HPV-11 were demonstrated when monoclonal antibodies or patient serum preincubated with HPV-11 virions prevented the infection of either of the two cell cultures, as shown by the absence of the E1--E4 mRNA transcript. Eleven (of 20) patients with CA were strongly ELISA reactive against HPV-11 virus-like particles. Five of these 11 patients also had detectable levels of neutralizing antibodies in their serum. It was also demonstrated that the neutralizing properties of the serum were titratable by endpoint dilution. None of 15 patients with CIN had detectable neutralizing antibodies against HPV-11. Neutralizing antibodies against HPV-11 can be detected in some patients with CA and the neutralizing effects of the patient sera can be titrated by endpoint dilution. The in vitro assay for the detection of neutralizing antibodies against HPV-11 may have utility for investigating the natural history of HPV infection and resolution, as well as assessing the efficacy of any putative HPV vaccine.

Animals↗
PubMed1997

Deficits of gaze stability in multiple axes following unilateral vestibular lesions.

Abnormalities in the vestibulo-ocular reflex (VOR) after unilateral vestibular injury may cause symptomatic gaze instability. We compared five subjects who had unilateral vestibular lesions with normal control subjects. Gaze stability and VOR gain were measured in three axes using scleral magnetic search coils, in light and darkness, testing different planes of rotation (yaw and pitch), types of stimulus (sinusoids from 0.8 to 2.4 Hz, and transient accelerations) and methods of rotation (active and passive). Eye velocity during horizontal tests reached saturation during high-velocity/acceleration ipsilesional rotation. Rapid vertical head movements triggered anomalous torsional rotation of the eyes. Gaze instability was present even during active rotation in the light, resulting in oscillopsia. These abnormal VOR responses are a consequence of saturating nonlinearities, which limit the usefulness of frequency-domain analysis of rotational test data in describing these lesions.

Adaptation, Physiological↗
PubMed1996

The 3D-structure of a natural inhibitor of cell adhesion molecule expression.

The three-dimensional structure of cyclopeptolide HUN-7293, a naturally-occurring inhibitor of cell adhesion molecule expression, has been determined from nuclear magnetic resonance data recorded in solution and from X-ray diffraction analysis of single crystals. The backbone conformation of HUN-7293 is characterized by two cis-peptide bonds in both the solution and crystalline state. Differences between the solution and crystal structure are visible for the orientation of some side chains and the strength of two transannular hydrogen bonds. Such structural information helps to provide insight into the molecular architecture of HUN-7293 on the atomic level and opens the way for structure-based modifications of this novel inhibitor of cell adhesion molecule expression.

Amino Acid Sequence↗
PubMed1996

T-cell receptor alpha beta and gamma delta T cells in rat and human skin--are they equivalent?

In the not-so-distant past the skin was generally viewed as a passive target for immune-mediated injury. Over the last decade, however, concepts of a previously unrecognized role for the skin have unfolded, whereby resident bone marrow-derived leukocytes (e.g. Langerhans cells and T cells) initiate and regulate the immune responses that protect it. Their combination with other immunomodulatory resident cells (e.g. keratinocytes, melanocytes, endothelial cells, fibroblasts) led to the idea that the skin may function as a self-sustaining lymphoid tissue. Although T lymphocytes or, at least, certain subpopulations thereof have the general propensity to populate epithelial tissues, there exist major species differences regarding the phenotype of intraepidermal T cells. The purpose of this review is to fill gaps in our understanding of the relationship of rodent skin T cells to T cells identified in human skin and the normal physiologic and pathologic role(s) of these cells.

Animals↗
PubMed1996

VCAM-1/alpha 4-integrin adhesion pathway: therapeutic target for allergic inflammatory disorders.

Lymphocyte recirculation and leukocyte extravasation involve a multistep process that is central to immune surveillance and the rapid response of white blood cells to sites of injury or infection. Interaction of vascular adhesion molecules (VCAM-1, ICAM-1, and selectins) with ligands on the leukocyte surface (integrins, carbohydrates, and mucin-like molecules) regulate diapedesis. The nature of an inflammatory stimulus ultimately determines the pattern of endothelial adhesion molecule expression and the avidity state of their counterreceptors, thus dictating to a large extent whether a subclass of leukocytes will play a dominant role in the immune response. Immunoglobulin superfamily member VCAM-1 recognizes alpha 4 beta 1 integrin, expressed on all leukocytes except neutrophils. Blockade or inhibition of VCAM-1/alpha 4 beta 1 interaction is expected to have therapeutic potential in treating various inflammatory disorders and autoimmune diseases since this adhesion pathway has a major influence on eosinophil, lymphocyte, and monocyte trafficking. This review summarizes some of the strategies that are currently used to selectively inhibit the VCAM-1/alpha 4 integrin pathway, including soluble VCAM-Ig fusion protein, peptide antagonists, antisense oligonucleotides, natural products, and neutralizing antibodies to VCAM-1 or alpha 4 integrin.

Animals↗
PubMed1996

Familial migraine with vertigo and essential tremor.

We report a family with dominantly inherited migraine headaches, episodic vertigo, and essential tremor. All symptoms improved with the use of acetazolamide. Linkage analysis ruled out linkage to markers on chromosome 19p, known to be linked to the genetic defect in families with the clinically similar syndromes of hemiplegic migraine and periodic ataxia. This genetic heterogeneity of migraine syndromes could result from defects in a family of genes coding proteins with similar properties.

Adult↗
PubMed1995

Nicotinic agonists administered into the fourth ventricle stimulate norepinephrine secretion in the hypothalamic paraventricular nucleus: an in vivo microdialysis study.

Nicotinic cholinergic agonists stimulate ACTH secretion by a central mechanism involving brainstem catecholamines. In vivo microdialysis studies were conducted to measure the release of norepinephrine (NE) in the hypothalamic paraventricular nucleus (PVN) in response to the administration of nicotine (Nic) or another nicotinic cholinergic (NAch) agonist, cytisine (Cyt), directly into the IVth ventricle. Alert, freely mobile rats, equipped 24 h previously with a chronic guide cannula in the IVth ventricle and microdialysis probe in the PVN, were injected with artificial cerebrospinal fluid (CSF, 500 nl/60 s), Nic (1-5 micrograms), or Cyt (1-25 micrograms) after three 20-min baseline samples had been taken. Analysis of the dialysates by HPLC with electrochemical detection demonstrated the dose-dependent secretion of PVN NE to Nic or Cyt with ED50s of approximately 1 or 6 micrograms, respectively; these were completely blocked by prior IVth ventricular injection of the NAch antagonist, mecamylamine (4 micrograms). In contrast, alpha-bungarotoxin, which antagonizes the action of NAch agonists by acting through the alpha 7 bungarotoxin-type NAchR, failed to reduce the NE response to Nic. Partial, but significant desensitization of NE secretion in response to a second injection of Nic (2.5 or 5 micrograms) 100 min after the first was seen, whereas NE responses to the second injection of Cyt (5 or 25 micrograms) were completely desensitized. However, cross-desensitization of each agonist to the other did not occur. This may reflect heterogeneity of the NAch receptor subtypes involved. The results of this study establish a correlation between the action of nicotine on brainstem norepinephrinergic regions and the resultant release of NE in the PVN, which would lead to the release of ACTH secretagogues.

Alkaloids↗
PubMed1994

Pharmacological modulation of endothelial cell-associated adhesion molecule expression: implications for future treatment of dermatological diseases.

Skin diseases with an inflammatory component, regardless of their etiology, are characterized at some point by the extravasation and subsequent infiltration of leukocytes into the dermal and/or epidermal compartments. This trafficking pattern is determined by a complex series of events whereby the leukocytes interact with cell adhesion molecules (CAM), particularly those induced on endothelial cells following activation with various inflammatory mediators. Vascular CAMs belonging to the selectin family (i.e., P-selectin and E-selectin) are thought to mediate early and reversible events involving leukocyte rolling and margination along the lumenal surface of microvascular cells (post-capillary venules). Certain members of the immunoglobulin supergene family (i.e., VCAM-1 and ICAM-1) regulate later and irreversible steps which lead to firm attachment and subsequent diapedesis of leukocytes. Accumulating evidence suggests that if one blocks the ligand-binding sites between leukocytes and endothelial cells, or inhibits vascular CAM expression, hematopoietic cell extravasation and progressive inflammatory events can be greatly diminished. To identify such inhibitors we developed a cell-based Elisa using the human microvascular cell line HMEC-1. As reported in the present paper, this approach yielded a naturally-occurring, low molecular weight compound which potently inhibits cytokine-induced adhesion molecule expression on cultured endothelial cells, without modulating "house-keeping" proteins.

Cell Adhesion Molecules↗
PubMed1994

Functional loss of the horizontal doll's eye reflex following unilateral vestibular lesions.

The doll's eye reflex represents the vestibulo-ocular reflex (VOR) elicited by high-acceleration head rotation. After complete unilateral vestibular lesions, the ipsilateral, horizontal doll's eye reflex is replaced by a series of "catch-up" saccades. These cause permanent symptoms of blurred vision and dizziness during ipsilateral turns. We compared normal controls and patients with complete surgical lesions or canal paresis of up to 9 years duration via electronystagmography (ENG) to determine the usefulness of the doll's eye test as a diagnostic test for complete vestibular lesions. This test was found to be more sensitive in diagnosis of such lesions than head-shaking nystagmus, rotatory directional preponderance, and spontaneous nystagmus. It is also useful to document VOR function in patients in whom caloric irrigation is contraindicated.

Adult↗
PubMed1994

Vestibular rehabilitation.

Vestibular rehabilitation is a physical therapy programme for persons with symptomatic lesions of the vestibular system. When applied early in the course of recovery, it can hasten compensation. It can also reduce symptoms resulting from permanent deficits caused by vestibular injury. It has been shown to be effective when applied to patients with unilateral or bilateral losses, and reduces both dizziness and imbalance. Compensation occurs through tonic re-balancing at the level of the vestibular nuclei; by substitution of vision, proprioception and peripheral sensation for the missing vestibular input; and by the use of behavioural strategies to deal with residual deficits. The latter two mechanisms can be facilitated with rehabilitation exercises. Treatment methods must be varied, based on the patient's underlying disorder. The best prognosis for full recovery is for individuals with acute, unilateral vestibular injury. Patients with bilateral lesions will show improvement, but will have permanent deficits. Persons with progressive vestibular disorders, those having central involvement and persons with visual or somatosensory impairments may require more prolonged courses of treatment or demonstrate incomplete recovery. Patients with a previous history of vestibular loss with recent decompensation require a thorough re-evaluation to rule out these more complex problems. Rehabilitation includes vestibular exercises, management of vestibular suppressant medications, general conditioning and patient instruction. Exercises should be directed at static and active posture and balance, eye-head co-ordination and symptomatic dizziness. Balance exercises include practice with standing, walking and turning. Eye-head co-ordination exercises require head movement during visual fixation or visual target changes. Treatment of symptomatic dizziness is based upon habituation to the provoking stimulus, usually head or eye movement. Home exercises are combined with formal physical therapy sessions and patient education to complete the process of rehabilitation.

Humans↗
PubMed1993

Nicotine stimulates the expression of cFos protein in the parvocellular paraventricular nucleus and brainstem catecholaminergic regions.

The rapid secretion of ACTH in response to nicotine is mediated by a central mechanism involving brainstem catecholaminergic regions. To identify specific brainstem regions involved in activating the hypothalamo-pituitary-adrenal axis and other areas of the brain by iv nicotine, immunocytochemical detection of cFos protein was used as a marker for neuronal activation. Nicotine (0.05 mg/kg) stimulated cFos expression in the parvocellular paraventricular nucleus (pcPVN; containing CRH-positive neurons mediating ACTH secretion); this correlated with the expression of cFos in the A2 (norepinephrinergic) and C2 (epinephrinergic) regions of the brainstem nucleus tractus solitarius, which project directly to the pcPVN. The selectivity of this brainstem activation was shown by the absence of responses in the locus coeruleus (LC), A1, and C1 catecholaminergic regions to this low dose of nicotine. In contrast, a high dose of nicotine (0.1 mg/kg), which produced a brief episode of tremor, was required for expression of cFos in the LC. This was associated with a further increase in the number of cFos-positive cells in the PVN, primarily through recruitment in the magnocellular region, a known projection field of LC. The higher dose of nicotine also induced cFos in the vasopressinergic region of the supraoptic nucleus (SON), whereas the lower dose of nicotine exclusively induced cFos in the oxytocinergic region of the SON. Limbic regions that receive catecholaminergic inputs, such as the the central nucleus of the amygdala (involved in PVN regulation) and the cingulate gyrus of the cortex, showed a dose-dependent increase in the number of cFos-positive cells after nicotine, whereas the dentate gyrus of the hippocampus only responded to the high dose. Thus, nicotine is a potent and selective stimulus for neuronal activation in brainstem catecholaminergic regions and their projection fields in the pcPVN and SON, which regulate the hypothalamo-pituitary-adrenal axis and vasopressin/oxytocin secretion, respectively.

Adrenocorticotropic Hormone↗
PubMed1993

Selective administration of nicotine into catecholaminergic regions of rat brainstem stimulates adrenocorticotropin secretion.

Nicotine (Nic) is a potent stimulus for ACTH secretion, and this response appears to be mediated by central catecholamine secretion. We have previously shown that fourth ventricular administration of Nic rapidly elevated plasma ACTH levels, that a nicotinic cholinergic antagonist, mecamylamine, instilled into the fourth ventricle inhibited the ACTH response to iv Nic, and that Nic stimulated norepinephrine secretion in the hypothalamic paraventricular nucleus. Thus, the present investigations sought to identify Nic-responsive regions in the brainstem that give rise to ascending catecholaminergic afferents resulting in ACTH secretion. Chronic brain and jugular cannulae were implanted, and Nic (50 nl over 30 sec) was infused into the locus coeruleus (LC), nucleus of the solitary tract (NTS -C2 or -A2 regions), C1, or A1 cell regions of freely moving, adult male rats. Injection of Nic (free base, 0.25-10 micrograms) into either the C2 or A2 region of NTS resulted in a dose-dependent increase in plasma ACTH. In contrast, C1 was unresponsive and A1 only showed responses to the highest doses of Nic (5 or 10 micrograms). In LC, Nic in doses of 2.5 micrograms or higher was required to elevate plasma ACTH. This dose is approximately 10-fold greater than that required in NTS-A2. Finally, mecamylamine (0.25 mg/kg body wt, iv), administered 2 min before Nic, abolished the ACTH responses in both C2 and A2 and significantly reduced the 7-min peak ACTH response in LC (P < 0.05). In summary, microinjection of Nic selectively activated the brainstem regions under investigation, with a rank order of sensitivity to Nic that was NTS-A2 > NTS-C2 > LC > A1 > C1 = cerebrospinal fluid. Therefore, systemically administered Nic appears to activate multiple catecholaminergic brainstem regions that are involved in mediating ACTH secretion.

Adrenocorticotropic Hormone↗
PubMed1992

Calcitonin gene-related peptide is chemotactic for human T lymphocytes.

Certain neuropeptides, such as CGRP, are associated with C-type nerve fibers in the skin and are known to be proinflammatory mediators. Because of their probable role in various cutaneous diseases, we investigated the effect of alpha- and beta-CGRP on human leukocyte migration in a 48-well microchemotaxis chamber using a 5-microns-pore filter. Elutriated peripheral blood leukocytes (enriched 80-90% for CD3+ and 10-20% for CD20+ lymphocytes) were added to the upper wells, and CGRP to the lower ones in a dose range of 10(-19)-10(-5) M; both were diluted in RPMI medium containing 0.05% fetal calf serum. The chamber was incubated at 37 degrees C for 2.5 hours, and the filter was washed and stained. The mean number of cells migrating through the filter was calculated for quadruplicate wells in each treatment group. Chemotactic activity was expressed as a migration index (MI = number of cells responding to CGRP/media control). Both alpha- and beta-CGRP were optimally chemotactic for leukocytes at approximately 50 pM, with a mean migration index of 11.5 for filter-adherent cells (n = 13 experiments); migration due to chemokinesis was minimal, as measured by checkerboard analysis. Almost all leukocytes that responded to CGRP were T cells (TCs), and the CD4 to CD8 ratio was similar to that of the input population; B cells were not observed. CGRP-induced migration appears to be a specific receptor-mediated event, as pretreating the cells with CGRP resulted in significant down-regulation of their chemotactic response to CGRP, but not to interleukin-1 alpha. Our data suggest that the release of CGRP from free nerve endings near the dermal-epidermal junction could influence cutaneous TC trafficking. As neuropeptides exacerbate (possibly initiate) the inflammatory process, they are likely to be important pharmacological targets in dermatological disorders.

Antigens, CD↗