Dopamine antagonists in the orbital prefrontal cortex reduce prepulse inhibition of the acoustic startle reflex in the rat

Schizophrenia is characterized by, among other things, (a) information processing deficits that have been indexed by a number of measures, including deficits in prepulse inhibition (PPI) of the acoustic startle reflex; and (b) pathophysiology of the frontal lobe. Recent studies have implicated the prefrontal cortex (PFC) in the modulation of PPI in rats. These studies suggest that dopamine (DA) ablation of the PFC (using 6-OHDA) leads to disruption of PPI. To better understand the role of DA type 1 (D1) and type 2 (D2) receptors in the modulation of PPI, we investigated the effects of two pharmacologically distinct DA antagonists on the modulation of PPI. Microinjection of SCH23390 (a D1 antagonist) into the orbital PFC markedly decreased PPI (at 0.1, 0.5, and 1.5 microg), whereas raclopride (a D2 antagonist) decreased PPI at some doses (0.1 and 0.5 mg/ml) but not at others (5.0 microg). We conclude that both D1 and D2 receptors mediate the cortical modulation of PPI.

The conserved SOCS box motif in suppressors of cytokine signaling binds to elongins B and C and may couple bound proteins to proteasomal degradation

The suppressors of cytokine signaling (SOCS) family of proteins act as intracellular inhibitors of several cytokine signal transduction pathways. Their expression is induced by cytokine activation of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway and they act as a negative feedback loop by subsequently inhibiting the JAK/STAT pathway either by direct interaction with activated JAKs or with the receptors. These interactions are mediated at least in part by the SH2 domain of SOCS proteins but these proteins also contain a highly conserved C-terminal homology domain termed the SOCS box. Here we show that the SOCS box mediates interactions with elongins B and C, which in turn may couple SOCS proteins and their substrates to the proteasomal protein degradation pathway. Analogous to the family of F-box-containing proteins, it appears that the SOCS proteins may act as adaptor molecules that target activated cell signaling proteins to the protein degradation pathway.

The contextual change paradox is still unresolved: comment on Bouton, Nelson, and Rosas (1999)

According to the contextual change theory of memory loss, spontaneous forgetting reflects a retrieval impairment due to subtle and unprogrammed shifts in environmental cues over a retention interval. However, Riccio, Richardson, and Ebner (1984) noted an apparent paradox in this model; specifically, laboratory studies inducing explicit shifts in contextual cues found less disruption of performance as retention intervals increased. Bouton, Nelson, and Rosas (1999) critiqued several of the claims made by Riccio et al. and concluded that the contextual cue theory is still a valid account of spontaneous forgetting. In this comment, the authors address the 3 major criticisms offered by Bouton et al., point out an inconsistency in their argument, and conclude that the original paradox still poses problems for the contextual change theory of forgetting.

Shock sensitization of startle in rats: the role of contextual conditioning

The role of contextual conditioning in the shock sensitization of startle effect was examined in 2 experiments with rats. Experiment 1 showed that shock sensitized the startle response only if it was given in the test context, and Experiment 2 showed that the sensitization effect was abolished in subjects preexposed to the test context. Taken together, these results show that shock sensitization of startle is mediated by contextual conditioning. The implications of this finding for using the shock sensitization of startle procedure as a model preparation for examining the neural and pharmacological bases of unconditioned fear are discussed.

The glenolabral articular disruption lesion: MR arthrography with arthroscopic correlation

OBJECTIVE

The purpose of this study was to describe the MR arthrography appearance of the glenolabral articular disruption (GLAD) lesion. Proper diagnosis of this lesion is important because it can be a source of persistent shoulder pain that requires surgical repair and because it is often difficult to diagnose clinically.

MATERIALS AND METHODS

Findings on MR arthrography were retrospectively correlated with the clinical histories and physical examination findings of six patients in whom we saw the typical appearance of the GLAD lesion. Four of these patients underwent follow-up arthroscopy that included surgical proof of GLAD lesions.

RESULTS

Five of the six patients had a documented glenohumeral impaction injury associated with an abducted externally rotated shoulder. All six patients had persistent shoulder pain, but their shoulders were stable during routine examination. In all patients, MR arthrography showed a superficial tear of the anteroinferior labrum with an adjacent articular cartilage injury. The torn labrum remained firmly attached to the anterior scapular periosteum, and contrast material was seen to extend into the labral tear and cartilaginous defect.

CONCLUSION

The MR arthrography findings of GLAD lesions include a nondisplaced tear of the anteroinferior labrum with an adjacent chondral injury. The pattern of chondral injury can range from a cartilaginous flap tear to a depressed osteochondral injury of the articular cartilage and underlying bone.

Shock sensitization of startle in rats: the role of contextual conditioning

The role of contextual conditioning in the shock sensitization of startle effect was examined in 2 experiments with rats. Experiment 1 showed that shock sensitized the startle response only if it was given in the test context, and Experiment 2 showed that the sensitization effect was abolished in subjects preexposed to the test context. Taken together, these results show that shock sensitization of startle is mediated by contextual conditioning. The implications of this finding for using the shock sensitization of startle procedure as a model preparation for examining the neural and pharmacological bases of unconditioned fear are discussed.

An increase in extracellular glutamate is a sensitive method of detecting ischaemic neuronal damage during cranial base and cerebrovascular surgery. An in vivo microdialysis study

All patients undergoing neurological surgery are at risk for serious complications. Ischaemic damage presenting with hemiparesis or speech difficulties occurs in up to 6% of patients undergoing cerebral bypass procedures and other complicated neurosurgical procedures. Currently available methods for detection of such damage include the use of somatosensory evoked potentials (SSEPs) and electro-encephalography (EEG). Unfortunately, these techniques have false positives and may remain normal in the presence of severe focal neurological deficits. Early detection of potential deficits may prevent or minimize damage through a change in operative or anaesthetic strategy. With the availability of several potential neuroprotective compounds, it is also possible to treat patients at risk of developing ischaemic complications if the individuals are identified early. The excitatory neurotransmitter glutamate is not only a metabolic product, but is also thought to promote ischaemia induced cell injury if released into the extracellular space. It may be a significant parameter for ischaemic brain metabolism. In this report we describe 10 patients who underwent extracranial-intracranial (EC-IC) high flow bypass procedures with routine intra-operative monitoring (IOM) as well as intra-operative in-vivo microdialysis measurement of glutamate. Our aim was to compare intra-operative microdialytic findings and IOM findings with respect to patients' early postoperative clinical courses. Three patients had significant intra-operative glutamate increases indicating ischaemia. Two of these patients awoke with a new neurological deficit (hemiparesis). Routine IOM findings were either normal or showed only transient changes during the time the glutamate levels were high. Our study shows that an increase in extracellular glutamate, as monitored by in-vivo microdialysis, is an excellent early market of neuronal damage. While our glutamate measurements were done off-line, it may be possible to get in future continuous on-line measurements to serve as an early warning system for potential ischaemic damage.

Opiates transdeactivate chemokine receptors: delta and mu opiate receptor-mediated heterologous desensitization

An intact chemotactic response is vital for leukocyte trafficking and host defense. Opiates are known to exert a number of immunomodulating effects in vitro and in vivo, and we sought to determine whether they were capable of inhibiting chemokine-induced directional migration of human leukocytes, and if so, to ascertain the mechanism involved. The endogenous opioid met-enkephalin induced monocyte chemotaxis in a pertussis toxin-sensitive manner. Met-enkephalin, as well as morphine, inhibited IL-8-induced chemotaxis of human neutrophils and macrophage inflammatory protein (MIP)-1alpha, regulated upon activation, normal T expressed and secreted (RANTES), and monocyte chemoattractant protein 1, but not MIP-1beta-induced chemotaxis of human monocytes. This inhibition of chemotaxis was mediated by delta and micro but not kappa G protein-coupled opiate receptors. Calcium flux induced by chemokines was unaffected by met-enkephalin pretreatment. Unlike other opiate-induced changes in leukocyte function, the inhibition of chemotaxis was not mediated by nitric oxide. Opiates induced phosphorylation of the chemokine receptors CXCR1 and CXCR2, but neither induced internalization of chemokine receptors nor perturbed chemokine binding. Thus, inhibition of chemokine-induced chemotaxis by opiates is due to heterologous desensitization through phosphorylation of chemokine receptors. This may contribute to the defects in host defense seen with opiate abuse and has important implications for immunomodulation induced by several endogenous neuropeptides which act through G protein-coupled receptors.

Effects of home-nest odors on the startle response in preweanling rats

The present study examined the effects of a highly preferred, biologically relevant olfactory stimulus (i.e., home-nest odors) on the startle response in preweanling rats. Although the rats detected the odor (as revealed by reductions in ultrasound vocalizations) it had no effect on either the initial magnitude of the startle response or habituation of this response across 80 test trials. These results are discussed in relation to recent studies on modulation of the startle response in developing rats, the effects of olfactory stimuli on the startle response, and the pleasure-attenuation of startle in nonhuman subjects.

The Effect of Duration of Individual Housing on Social Behavior of Adult Male Bonnet Macaques (Macaca radiata)

Project constraints often require social primates, such as macaques, to be housed individually. However, we believed the amount of time spent housed alone prior to renewed social exposure would effect an animal's behavior. We observed the behavior of adult male bonnet macaques (Macaca radiata) during time spent in an exercise pen with other adult males. We studied 2 groups (n = 3 males/group). Group one (group LT) was composed of males that had been housed alone for 24 months prior to the study, and the other group (group ST) consisted of male macaques that had been housed alone for 1 month prior to the study. One day each week for 8 weeks, members of each group were placed in an exercise pen containing items that would encourage foraging and object exploration. Seven 5-min focal observations were recorded for macaques during each session. The 2 most notable differences in social behavior were that macaques of group LT spent significantly (P = 0.003) more time alone than did macaques of group ST, whereas macaques of group ST spent significantly (P = 0.002) more time involved in social grooming than did macaques of group LT. Thus, prior duration of prior individual housing appeared to significantly affect social behavior.

The role of personal tutor in nurse education: towards an understanding of practice in a college of nursing and midwifery at a particular point in time

This paper describes an inquiry to increase understanding of the role of personal tutor in a college of nursing and midwifery. Concepts of tutor and role are discussed in relation to their historical influences and an over view is provided of the research process which included document analysis and reflective audio-taped interviews with student nurses, teachers and education managers. Five conceptual categories are identified and critically analysed in relation to personal, institutional and social contexts and the factors which influence them. The first two categories identified reflect the concepts discussed in the literature. The third category reflects the uncertainties and confusion which surround differing perceptions of the role. The fourth category suggests the misunderstandings which may occur through taking for granted apparently shared concepts. The fifth category suggests the significance of personal theory in practice and the extent to which roles are taken or made. Traditional values concerning theory and practice are thus challenged. The reflective evidence provided by the participants suggests a theory, generated by them through the meanings they give to their views and actions, concerning their roles and the situation in which they find themselves at a particular point in time.

Emergence of conditioned cardiac responses to an olfactory CS paired with an acoustic startle UCS during development: form and autonomic origins

Pairing an olfactory conditioned stimulus (CS) with an acoustic startle unconditioned stimulus (UCS) produced conditioned bradycardia in rats ranging from 12 days of age to adulthood but failed to produce conditioning in 10-day-olds (Experiment 1). The second experiment compared the effects of two different UCSs, acoustic startle and electric shock. The startle UCS produced conditioned bradycardia accompanied by immobility. In contrast, the shock UCS produced conditioned tachycardia accompanied by behavioral activation. Pharmacological analysis revealed that activation of the parasympathetic nervous system (PNS) produced the conditioned bradycardia (Experiment 3) and that activation of the sympathetic nervous system (SNS) produced the conditioned tachycardia (Hunt, Hess, & Campbell, 1994). Further comparisons revealed that the startle UCS established conditioning several days earlier in development than the shock UCS. The ability of the PNS to respond to phasic stimulation earlier in development than the SNS was discussed as a possible mechanism for the early development of conditioned bradycardia.

Allocating resources: community involvement is not easy

Resources for health care are limited in all societies; decisions have to be made about who gets what health care. A case study is discussed. Jaymee Bowen was a British child whose Health Authority refused to provide free treatment for her advanced leukaemia. The media advertised her case and public opinion was mobilized in favour of treating her with public funds. Cost-effectiveness can be used to identify treatments that provide value-for-money. The public can express an opinion on what kinds of care are wanted--for example, what are the relative benefits of preventing morbidity or mortality, or of helping children rather than young people? Rational criteria can be developed with public involvement--in the case of Jaymee Bowen, the proposed treatment really did not appear to offer value-for money. But some individual cases that contradict the 'rational' criteria for the population as a whole will always be able to attract public sympathy and interest.

Petroclival and foramen magnum meningiomas: surgical approaches and pitfalls

The management of petroclival and foramen magnum meningiomas has been revolutionized by the techniques of cranial base surgery. However, these tumors are still among the most difficult cranial base lesions to treat. In this report, we discuss the classification, presenting symptoms, preoperative investigation, treatment indications, operative approaches and technique, postoperative complications and care, and results of surgery of petroclival and foramen magnum meningiomas. Careful analysis of tumor- and patient-related factors has helped us to predict which features can lead to postoperative problems in patients allowing surgeons to appropriately modify their behavior. The application of cranial base techniques-combined with new knowledge about the limitations of microsurgical resection-can greatly reduce postoperative morbidity in these patients.

Management and long-term outcome of adenoid cystic carcinoma with intracranial extension: a neurosurgical perspective

Adenoid cystic carcinoma is a tumor of minor and major salivary glands that often invades the cranial base and intracranial cavity via local and perineural spread. In the past, the role of neurosurgeons in managing these tumors has been limited. The growth of interdisciplinary cranial base surgical approaches has now increased the involvement of neurosurgeons in the management of these tumors. We present a series of 16 patients with adenoid cystic carcinomas with cranial base and intracranial extension, the largest series reported in the neurosurgical literature. We have focused our approach on a neurosurgical perspective and made recommendations for the treatment of these tumors in relation to the following specific aspects of this disease. 1) The management of the carotid artery: In our experience, when the carotid artery is involved by tumor, a preliminary cerebral revascularization procedure with a cervical carotid to middle cerebral artery vein bypass graft should be performed before tumor resection. 2) The management of the cavernous sinus and orbit: Cavernous sinus tumor should be removed as fully as possible, but every effort should be made to preserve the IIIrd and IVth cranial nerves to achieve optimal functional and cosmetic results. The orbit should be exenterated when there is intraconal involvement; otherwise, intraorbital tumor can be removed with orbital preservation. 3) The use of palliative surgery: We have found that the use of palliative surgery can be considered even in patients whose extent of local disease precludes a surgical cure. The slow progression of the disease allows for long-term survival of many patients with advanced local disease and even of those with metastatic disease. 4) The long-term survival of these patients: In our series, six patients had no evidence of local disease and a mean survival of 72 months, one living patient had evidence of local disease and has survived 56 months, eight patients died of disease, with a mean survival of 137 months, and one patient died of complications after surviving for 63 months.

Assessing abuse and neglect and dental fear in women

Little is known about how specific life stressors, such as sexual, physical and emotional abuse and neglect, might be factors in the establishment or maintenance of dental fears or might affect routine dental treatment. The authors collected data from 462 female members of a large urban health maintenance organization about their dental fear and histories of childhood and adult traumas. According to these data, a history of trauma appears to be significantly associated with elevated dental fear, although multiple factors play a major role in the establishment and maintenance of these phobias.

Cerebral amyloid angiopathy and plaques, and visceral amyloidosis in aged macaques

In the present study, we report our extended data on the incidence of two types of cerebral amyloidosis (plaques and plaques associated with angiopathy) and visceral amyloidosis in late adult and aged captive rhesus monkeys (Macaca mulatta). In a total of 81 brains from animals ranging from 16 to 39 years old, beta-amyloid plaques were found in 38, 10 of which were associated with amyloid angiopathy. Brains from eight adults, 16 to 19 years, had no lesions. In aged groups, the rates were 20.8% in the 20- to 25-year group (24), 60.9% in the 26- to 31-year group (41), and 100% in the 33- to 39-year group (8). Twelve monkeys in these aged groups had an involvement of amyloidosis in either the liver, the adrenal, or the pancreatic islets, and 7 of 12 had amyloid plaques (5) and plaques associated with cerebral angiopathy (2). No neurofibrillary tangles were detected in these brain lesions. Amyloid in both plaques and cerebral angiopathy showed immunocytochemical crossreactivity with human amyloid beta (beta/A4) and precursor proteins (APP-A4), but visceral amyloid was negative. Ultrastructurally, amyloid initially appears as loose filaments in the perivascular or Disse space, and they further aggregate to produce dense interlacing bundles. Cerebral amyloid angiopathy associated with plaque appears to be a subclass of senile plaque lesions in aged monkeys as well as in aged humans, and it appears to have no pathogenetic correlation with visceral amyloidosis.

Comparison of carbon dioxide and normal saline for uterine distension in outpatient hysteroscopy

OBJECTIVE

To evaluate patient acceptance and the clinical feasibility of carbon dioxide compared with normal saline for uterine distension in outpatient hysteroscopy.

DESIGN

Prospective, randomized clinical trial.

SETTING

Outpatient hysteroscopy clinic in a university hospital.

PATIENTS

One hundred fifty-seven patients undergoing outpatient hysteroscopy.

INTERVENTIONS

Outpatient hysteroscopy was performed with carbon dioxide or normal saline with endometrial biopsy when indicated.

MAIN OUTCOME MEASURES

Need for local anesthesia, cervical dilatation, view of uterine cavity, need to change from carbon dioxide to normal saline distension, procedure time, patient discomfort (lower abdominal pain, shoulder tip pain, nausea) and complications.

RESULTS

Carbon dioxide was used for uterine distension in 79 women and normal saline was used in 78. Cervical dilatation was required more often with carbon dioxide hysteroscopy, although there was no increased requirement for local anesthesia. Hysteroscopic vision was similar between the two media, but eight carbon dioxide cases had to be converted to liquid distension. Procedure times were significantly longer for carbon dioxide hysteroscopy as was the occurrence of bubbles during the procedure. Lower abdominal pain and shoulder tip pain were significantly worse with carbon dioxide distension. Although the incidence of nausea and vomiting was higher with the use of carbon dioxide, the differences did not achieve statistical significance.

CONCLUSION

The use of normal saline for uterine distension had no adverse affects on the hysteroscopic view. It provided a shorter operating time and was well accepted by patients. Because of its easy availability and low cost, normal saline is an excellent alternative to carbon dioxide in women undergoing outpatient hysteroscopy.