Sleep disorders: a risk factor for pseudotumor cerebri?

OBJECTIVE

To determine whether sleep-related breathing disorders are common in patients with idiopathic intracranial hypertension.

MATERIALS AND METHODS

Medical records of 53 patients with idiopathic intracranial hypertension from a tertiary center neuroophthalmology practice were reviewed. Thirty-seven patients were identified who had a history of snoring, difficulty sleeping, or daytime somnolence. The data from polysomnograms were tabulated to determine the frequency of apneas, hypopneas, and arousals.

RESULTS

Fourteen of 37 patients with idiopathic intracranial hypertension and symptoms of sleep disturbance underwent polysomnography. There were two men and 12 women varying in age from 24 to 58 years (mean, 39.4 +/- 11.9). These patients were obese with body mass indexes varying from 33.0 to 63.2 (mean, 46.0 +/- 9.5). A diagnosis of sleep apnea was made in six and upper airway resistance syndrome in seven patients.

CONCLUSIONS

Sleep-related breathing problems were common in our patients with idiopathic intracranial hypertension. Obesity was common in these patients and may be playing a causative role in sleep apnea and idiopathic intracranial hypertension. It is suggested that idiopathic intracranial hypertension patients who have symptoms of sleep disturbance should be further evaluated for the presence of sleep-related breathing problems.

Blockade of lactate transport exacerbates delayed neuronal damage in a rat model of cerebral ischemia

Studies over the past decade have demonstrated that lactate is produced aerobically during brain activation and it has been suggested to be an obligatory aerobic energy substrate postischemia. It has been also hypothesized, based on in vitro studies, that lactate, produced by glia in large amounts during activation and/or ischemia/hypoxia, is transported via specific glial and neuronal monocarboxylate transporters into neurons for aerobic utilization. To test the role of lactate as an aerobic energy substrate postischemia in vivo, we employed the cardiac-arrest-induced transient global cerebral ischemia (TGI) rat model and the monocarboxylate transporter inhibitor alpha-cyano-4-hydroxycinnamate (4-CIN). Once 4-CIN was establish to cross the blood--brain barrier, rats were treated with the inhibitor 60 min prior to a 5-min TGI. These rats exhibited a significantly greater degree of delayed neuronal damage in the hippocampus than control, untreated rats, as measured 7 days post-TGI. We concluded that intra-ischemically-accumulated lactate is utilized aerobically as the main energy substrate immediately postischemia. Blockade of lactate transport into neurons prevents its utilization and, consequently, exacerbates delayed ischemic neuronal damage.

The glucose paradox in cerebral ischemia. New insights

The present in vivo findings that lactate, accumulated during an ischemic episode, is an essential aerobic energy substrate during the initial postischemic period are in full agreement with out in vitro findings. Moreover, the beneficial effects of hyperglycemia are also in agreement with our and others' in vitro results that have demonstrated a neuroprotective effect of glucose against hypoxic change. The aggravation of ischemic delayed neuronal damage by glucose loading 15 min prior to the ischemic insult is likely the result of glucose induction of a short-acting (30 to 60 min) systemic factor (hormonal?) that, when combined with an ischemic insult, potentiates the ischemic damage.

In vitro, animal, and human characterization of OPTISON infusions for myocardial contrast echocardiography

Traditionally, performing myocardial contrast echocardiography with OPTISON required maximal bolus dosing. However, sustained and consistent opacification of the myocardium would be preferable for perfusion imaging.

METHODS

Images of 5 anesthetized dogs and 6 human volunteers were obtained with a second harmonic ultrasound system during bolus administration of OPTISON and 2 infusion techniques. One infusion technique used diluted OPTISON, and the other used the buoyant properties of OPTISON microspheres by placing the contrast agent between an infusion source and the intravenous site in a vertically oriented extension line (ELT). Myocardial intensities and in vitro microsphere characteristics were analyzed to assess the consistency of microsphere delivery over time.

RESULTS

In addition to providing higher myocardial opacification intensity than diluted infusions, ELT infusions provided consistent microsphere concentration, phantom enhancement, and near-peak bolus-level myocardial opacification for 7 to 15 minutes. The myocardial intensity at 3 and 5 minutes in human subjects during ELT infusions (30 mL/h; 2.5 mL) was lower (220 arbitrary units [au] and 165 au, respectively) but not significantly different (P =.3 and.1, respectively) than the peak myocardial intensity (265 au) after bolus administration.

CONCLUSION

This new ELT infusion method provides an acceptable alternative to bolus administration of OPTISON for prolonged myocardial opacification.

The Contributions of Wayne Ruppenthal to the Field of Music Therapy

This paper examines the career of Wayne Ruppenthal, considered one of the early pioneers in the field of music therapy. He began his practice in the late 1940s and his clinical accomplishments at Topeka State Hospital, spanned nearly two decades during the height of Freudian psychoanalysis and "milieu" therapy prescribed by The Menninger Foundation. Ruppenthal received his education at The University of Kansas in Lawrence, Kansas, and was the first graduate of the Master's of Music Education in Functional Music program in 1948. His contributions to the profession were significant and enduring and included establishing formal clinical practice and training standards, assisting with development of the National Association for Music Therapy (NAMT), and promoting the credibility of music therapy through published research. He retired from Topeka State Hospital in 1968. This paper is dedicated to the memory of Wayne Ruppenthal, who died on August 31, 1997.

Failure to demonstrate therapeutic tachyphylaxis to topically applied steroids in patients with psoriasis

BACKGROUND

Tachyphylaxis, defined as a rapidly decreasing response to a physiologically active agent after administration of a few doses, can be well demonstrated in the experimental setting. However, tachyphylaxis in the clinical setting lacks clear demonstration.

OBJECTIVE

Our purpose was to identify dermatologists' perception of the clinical incidence of tachyphylaxis and then design a prospective study that would estimate the clinical incidence of tachyphylaxis.

METHODS

Clinical and academic dermatologists completed a survey questionnaire about the incidence of tachyphylaxis and the time course to its occurrence. Subjects with plaque psoriasis applied topical corticosteroid twice daily for 12 weeks to their plaques, leaving an isolated plaque untreated for comparison. Plaques were evaluated every 2 weeks. By means of a 9-point scale, an end point for clinical detection of tachyphylaxis was defined as "an increase in plaque elevation of at least 2 occurring after a detectable decrease in plaque elevation with topical steroid."

RESULTS

The survey found that 57% of dermatologists perceived that tachyphylaxis occurred after 8 weeks of therapy with topical corticosteroid. In the 12-week clinical study, none of 32 patients exhibited detectable signs of tachyphylaxis.

CONCLUSION

What accounts for the commonly held belief of tachyphylaxis in the clinical setting may be related to the therapeutic efficacy of topical corticosteroids. Failure of topical corticosteroids to clear psoriasis after an initial improvement may give the impression of tachyphylaxis. The common clinical perception of tachyphylaxis may also be related to issues of compliance outside a study setting or a psoriasis flare unrelated to therapy.

Fosphenytoin reduces hippocampal neuronal damage in rat following transient global ischemia

Fosphenytoin, a water-soluble disodium phosphate ester of phenytoin, is a phenytoin prodrug with similar anticonvulsant properties. In this study, we evaluated its neuroprotective properties in a cardiac arrest-induced global ischemia model. After 12 minute ischemia, Long-Evans hooded rats were resuscitated, given fosphenytoin (30 mg/kg, i.m.) or saline 5 minutes after the ischemic episode, and killed on day 7. Brains were removed, fixed, and vibratome sectioned to assess the numbers of normal appearing CAI pyramidal neurons and for immunohistological staining of glial fibrillary acidic protein (GFAP). After global ischemia, the number of hippocampal CA1 pyramidal neurons decreased significantly (from 14.33 +/- 1.73 to 2.19 +/- 0.16 per 100 micron 2). Most hippocampal CA1 pyramidal neurons showed signs of injury and GFAP immunoreactivity of the region increased. With fosphenytoin treatment 5 min after ischemia, hippocampal CA1 pyramidal neurons remained at near control level (13.90 +/- 0.92), however, GFAP staining was not significantly changed. Our data, although indicating different neuronal and glial responses following fosphenytoin treatment, nevertheless, suggest that fosphenytoin is an effective neuroprotectant against ischemia-induced damage.

Study of cerebral energy metabolism using the rat hippocampal slice preparation

This article describes methods and experimental paradigms used in combination with the rat hippocampal slice preparation in an attempt to better understand cerebral energy metabolism under the following conditions: normal resting conditions, conditions of oxygen and/or glucose deprivation, and conditions of activation (excitation). The outcome of this attempt, as described herewith, demonstrates the unmatched usefulness of the brain slice preparation as an in vitro tool in the field of neuroscience.

Accentuated viral exanthems in areas of inflammation

Types of lesions and patterns of distribution aid in the recognition of viral exanthems. Varicella and hand-foot-and-mouth disease can appear atypically in areas of inflammation. We describe 5 cases of morphologically altered exanthems that localized early and preferentially to areas of inflammation.

An increase in lactate output by brain tissue serves to meet the energy needs of glutamate-activated neurons

Aerobic energy metabolism uses glucose and oxygen to produce all the energy needs of the brain. Several studies published over the last 13 years challenged the assumption that the activated brain increases its oxidative glucose metabolism to meet the increased energy demands. Neuronal function in rat hippocampal slices supplied with 4 mM glucose could tolerate a 15 min activation by a 5 mM concentration of the excitatory neurotransmitter glutamate (Glu), whereas slices supplied with 10 mM glucose could tolerate a 15 min activation by 20 mM Glu. However, in slices in which neuronal lactate use was inhibited by the lactate transporter inhibitor a-cyano-4-hydroxycinnamate (4-CIN), activation by Glu elicited a permanent loss of neuronal function, with a twofold to threefold increase in tissue lactate content. Inhibition of glycolysis with the glucose analog 2-deoxy-D-glucose (2DG) during the period of exposure to Glu diminished normal neuronal function in the majority of slices and significantly reduced the number of slices that exhibited neuronal function after activation. However, when lactate was added with 2DG, the majority of the slices were neuronally functional after activation by Glu. NMDA, a nontransportable Glu analog by the glial glutamate transporter, could not induce a significant increase in slice lactate level when administered in the presence of 4-CIN. It is suggested that the heightened energy demands of activated neurons are met through increased glial glycolytic flux. The lactate thus formed is a crucial aerobic energy substrate that enables neurons to endure activation.

Granulocyte-macrophage colony-stimulating factor induces activation and restores respiratory burst activity in monocytes from septic patients

Monocyte activation in response to recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) was examined in vitro in septic shock patients. These monocytes exhibited a greater respiratory burst activity than monocytes from healthy subjects; the response to secondary stimulation with bacterial stimuli was attenuated. GM-CSF restored the ability of monocytes to respond appropriately to secondary stimulation. Expression of certain integrin adhesion molecules, L-selectin, and Fcgamma receptors was increased on monocytes of septic shock patients; expression of CD11c was reduced. GM-CSF up-regulated integrin expression and decreased L-selectin, FcgammaRII, and FcgammaRIII expression. Septic patients exhibited greater biologic activity of monocyte tissue factor than did healthy subjects. Priming monocytes with GM-CSF accelerated tissue factor activation following stimulation with lipopolysaccharide and bacterial culture supernatant. Certain parameters of monocyte function may be restored by exposure to GM-CSF. This benefit may be offset by an increase in monocyte procoagulant activity.

Glia are the main source of lactate utilized by neurons for recovery of function posthypoxia

Experiments are described in which a rat hippocampal slice preparation was used along with the metabolic glial inhibitor, fluorocitrate (FC), to investigate the role of glial-made lactate and its shuttling to neurons in posthypoxia recovery of synaptic function. After testing two less effective concentrations of FC, only 10.1 +/- 6.5% of slices treated with 100 microM of the metabolic toxin recovered synaptic function at the end of 10-min hypoxia and 30-min reoxygenation. In contrast, 79.6 +/- 7.4% of control, untreated slices recovered synaptic function after 10-min hypoxia and 30-min reoxygenation. The low rate of recovery of synaptic function posthypoxia in FC-treated slices occurred despite the abundance of glucose present in the medium before, during, and after hypoxia. The amount of lactate produced by FC-treated slices during the hypoxic period was only 62% of that produced by control, untreated slices. Supplementing FC-treated slices with exogenous lactate significantly increased the posthypoxia recovery rate of synaptic function. These results strongly support our previous findings concerning the mandatory role of lactate as an aerobic energy substrate for the recovery of synaptic function posthypoxia and clearly show that the bulk of the lactate needed for this recovery originates in glial cells.

Sarcoid myopathy: imaging findings

Sarcoidosis is a granulomatous multisystem disorder that may uncommonly involve muscle. Muscular sarcoid may be nodular, atrophic myopathic, or acute myositic. We illustrate a case of the myopathic type of muscular sarcoid that is unusual because the abdominal wall muscles, rather than the extremity muscles, were involved. Muscular involvement by sarcoid should be considered in the differential diagnosis of focal muscle disease, especially in a patient with a known history of sarcoid. The presence of typical bilateral hilar adenopathy on a chest radiograph as well as the presence of abdominal findings (hepatosplenomegaly and retroperitoneal adenopathy) may help establish the diagnosis. Otherwise, sonographically guided biopsy may be necessary for definitive diagnosis.

Strategies for getting students on the information superhighway

Many nurses indicate that they lack the formal education needed to use resources such as the Internet and computer technology related to healthcare. The results of a survey at a baccalaureate school of nursing revealed that although nearly 100% of those surveyed used computers, very few effectively used available Internet resources. In response, the authors implemented strategies to make available Internet resources "user-friendly" for communication and information gathering.

Brain lactate is an obligatory aerobic energy substrate for functional recovery after hypoxia: further in vitro validation

This study used the rat hippocampal slice preparation and the monocarboxylate transporter inhibitor, alpha-cyano-4-hydroxycinnamate (4-CIN), to assess the obligatory role that lactate plays in fueling the recovery of synaptic function after hypoxia upon reoxygenation. At a concentration of 500 microM, 4-CIN blocked lactate-supported synaptic function in hippocampal slices under normoxic conditions in 15 min. The inhibitor had no effect on glucose-supported synaptic function. Of control hippocampal slices exposed to 10-min hypoxia, 77.8 +/- 6.8% recovered synaptic function after 30-min reoxygenation. Of slices supplemented with 500 microM 4-CIN, only 15 +/- 10.9% recovered synaptic function despite the large amount of lactate formed during the hypoxic period and the abundance of glucose present before, during, and after hypoxia. These results indicate that 4-CIN, when present during hypoxia and reoxygenation, blocks lactate transport from astrocytes, where the bulk of anaerobic lactate is formed, to neurons, where lactate is being utilized aerobically to support recovery of function after hypoxia. These results unequivocally validate that brain lactate is an obligatory aerobic energy substrate for posthypoxia recovery of function.

Hepatosplenic cat-scratch disease and abdominal pain

BACKGROUND

There have been several recent reports that cat-scratch disease (CSD) causes a multiplicity of atypical clinical syndromes. We recently diagnosed hepatosplenic CSD in a child who was seen with fever and abdominal pain. We report this case and 10 other patients with hepatosplenic CSD and highlight the importance of abdominal pain in this clinical entity.

METHODS

This was a retrospective review of charts of patients with a diagnosis of cat-scratch disease at Egleston Children's Hospital between January, 1985, and June, 1996. From these cases patients with hepatosplenic CSD were selected for study.

RESULTS

Seven children (64%) had significant abdominal pain, and in three children abdominal pain was their chief complaint. All children in the study had pathologic evidence of CSD or elevated titers of antibodies to Bartonella henselae. Ultrasound examination showed that all children had microabscesses in the spleen, and eight had abscesses in the liver.

CONCLUSIONS

One of the most remarkable findings in this large series of cases of hepatosplenic CSD was that 64% of the patients complained of abdominal pain. All children in this study received antibiotics. It was our clinical impression that once antibiotics had been started, the patients appeared to improve very quickly. With an increased index of suspicion, the use of B. henselae serology and an abdominal ultrasound examination, the diagnosis of this underrecognized disease might be more readily made.

Brain lactate, not glucose, fuels the recovery of synaptic function from hypoxia upon reoxygenation: an in vitro study

Lactate has been considered for many years to be a useless, and frequently, harmful end-product of anaerobic glycolysis. In the present in vitro study, lactate-supplied rat hippocampal slices showed a significantly higher degree of recovery of synaptic function after a short hypoxic period than slices supplied with an equicaloric amount of glucose. More importantly, all slices in which anaerobic lactate production was enhanced by pre-hypoxia glucose overload exhibited functional recovery after a prolonged hypoxia. An 80% recovery of synaptic function was observed even when glucose utilization was blocked with 2-deoxy-D-glucose during the later part of the hypoxic period and during reoxygenation. In contrast, slices in which anaerobic lactate production was blocked during the initial stages of hypoxia did not recover their synaptic function upon reoxygenation despite the abundance of glucose and the removal of 2-deoxy-D-glucose. Thus, for brain tissue to show functional recovery after prolonged period of hypoxia, the aerobic utilization of lactate as an energy substrate is mandatory.