Genetically Distinct Oligosarcoma Arising from Oligodendroglioma: Systematic Review & Illustrative Case Example

BACKGROUND

Oligosarcoma is a rare central nervous system (CNS) neoplasm that may arise following oligodendroglioma resection, which demonstrates a unique genetic profile and aggressive clinical phenotype. We present a systematic review and illustrative case example emphasizing the clinical and prognostic features of this unusual and unfavorable neuro-oncologic disease.

METHODS

Systematic literature review and illustrative case report.

RESULTS

A 41-year-old man who had undergone 2 neurosurgical resections for a World Health Organization grade II oligodendroglioma (Ki-67 = 5-10%, 1p/19q codeleted, IDH2 mutated), without adjuvant chemoradiation, presented with seizures seven years after resection. An extra-axial mass was identified adjacent to the resection cavity, in which gross total resection was achieved. Pathology confirmed World Health Organization grade IV oligosarcoma (Ki-67 = 20%). Adjuvant chemoradiation was initiated, with disease control observed over 6 months of follow-up. Seven publications met inclusion criteria. Oligosarcoma has been confirmed in 36 lesions, arising in 35 patients; 5 were primary oligosarcoma, while 31 occurred in the setting of prior resected oligodendroglioma or oligoastrocytoma. Features shared by these lesions include regain of H3K27me3 expression, 1p/19q codeletion, homozygous deletion of CDKN2A/B, loss of 6q, loss of NF1 and YAP1, and attenuation of CpG island methylator. Median survival after oligosarcoma diagnosis was 1.3 years (range, 0-5.2; n = 35).

CONCLUSIONS

Oligosarcoma is a prognostically unfavorable CNS neoplasm with characteristic imaging and pathologic features, and a strong association with previously resected oligodendroglioma. Aggressive treatment is recommended, including gross total resection and adjuvant chemoradiation. Further study is required to define optimal treatment protocol for this CNS malignancy.

Dialysis disequilibrium syndrome in neurosurgery: literature review and illustrative case example

INTRODUCTION

The dialysis disequilibrium syndrome (DDS) is a complication in those undergoing dialysis for chronic kidney disease (CKD) or acute kidney injury (AKI), characterized by nonspecific symptoms that may progress to coma and death secondary to cerebral edema. This syndrome is associated with rapid change in electrolytes during dialysis with changes in intracranial pressure (ICP) and may have a higher incidence in the elderly neurosurgical patient population.

METHODS

Literature review and illustrative case example.

RESULTS

A 62-year-old female presented with acute mental status change during hemodialysis (HD), with a history of a nonsurgical acute subdural hematoma (SDH) 10 days prior. Imaging showed a conversion of the acute SDH to chronic SDH of 12.2 mm in size with a 14.1 midline shift, for which she underwent a hemicraniectomy with SDH evacuation, with a gradual return to baseline. The literature review identified 5 publications meeting the inclusion criteria. Major theories of DDS include a reverse urea effect, intracerebral acidosis, idiogenic osmoles, and local inflammation. This complication may occur more frequently in the elderly neurosurgical patient population, likely due to age-related comorbidities, preexisting neurological insult, and increased permeability of the blood-brain barrier (BBB), leading to cerebral edema.

CONCLUSION

DDS is a rare and potentially fatal complication of HD that may have a higher incidence in the elderly neurosurgical patient population, yet remains to be fully understood. Further study is recommended to characterize the pathophysiological mechanism and incidence of DDS in neurosurgical patients.

Surgical management of spinal pathologies in the octogenarian: a narrative review

Optimal management paradigms of spinal pathologies in the octogenarian population are controversial given the higher incidence of comorbidities with concern for poor prognosis and fear of increased complications associated with surgical management. In this narrative review, we aim to detail the complex clinical considerations when approaching odontoid screw fixation/instrumented fusion, spinal decompression, and spinal fusion in the octogenarian. Literature review was conducted via Google Scholar and PubMed databases, with literature selected based on statistical power and clinical relevance to the following pathologies/surgical techniques: odontoid fracture, surgical decompression, and surgical fusion in the octogenarian. The aforementioned pathologies were selected based on prevalence in the advanced-age population in which surgical screening techniques and management remain nonuniform. Preoperative evaluation of the octogenarian patient increasingly includes frailty, sarcopenia, and osteopenia/osteoporosis assessments. In cases of odontoid fracture, conservative management appears to provide beneficial clinical outcomes with lower rates of complication compared to surgery; however, rates of radiographic odontoid fusion are far lower in conservatively managed patients. Regarding surgical decompression and fusion, the presence of comorbidities may be more predictive of outcome rather than age status, with the advent of minimally invasive techniques providing safety and efficacy in the surgical management of this age cohort. Age status may be less pertinent than previously thought in the decision to pursue spinal surgery for odontoid fracture, spinal decompression, or spinal fusion; however, each of these procedures has respective risks and benefits that must be considered within the context of each patient's comorbidity profile.

Arteriovenous malformation with unique drainage through the emissary vein of the foramen ovale: illustrative case

BACKGROUND

As part of the laterotrigeminal venous system (LTVS), the emissary vein of the foramen ovale (EVFO) is an underrecognized venous structure communicating between the cavernous sinus and pterygoid plexus. The sphenobasal sinus is an anatomical variation of the sphenoparietal sinus that drains directly into the EVFO. The authors present the case of a ruptured arteriovenous malformation (AVM) with a unique drainage pattern through the sphenobasal sinus and EVFO.

OBSERVATIONS

A 9-year-old female initially presented with loss of consciousness and was subsequently found to have a ruptured AVM in the left basal frontal area. She underwent an immediate decompressive hemicraniectomy, with a computed tomography angiogram demonstrating a unique anatomical variation in which the sphenobasal sinus communicated with the EVFO and LTVS. The final venous drainage returned to the pterygoid plexus and external jugular vein. Postoperatively, the patient made a substantial recovery, with generalized right-sided weakness remaining as the sole deficit.

LESSONS

The authors present the case of a ruptured AVM with unique venous drainage into the sphenobasal sinus and EVFO, for which the current literature remains limited. As exemplified by this illustrative case, technique modification may be warranted in the setting of this unique anatomical variation to avoid venous sinus injury.

A systematic review of the power of standardization in pediatric neurosurgery

In the current neurosurgical field, there is a constant emphasis on providing the best care with the most value. Such work requires the constant optimization of not only surgical but also perioperative services. Recent work has demonstrated the power of standardized techniques in limiting complication while promoting optimal outcomes. In this review article, protocols addressing operative and perioperative care for common pediatric neurosurgical procedures are discussed. These articles address how various institutions have optimized procedures through standardization. Our objective is to improve patient outcomes through the optimization of protocols.

Inferring diet, feeding behaviour and causes of mortality from prey-induced injuries in a New Zealand fur seal

New Zealand fur seals Arctocephalus forsteri are the most abundant of the 4 otariid (eared seal) species distributed across Australasia. Analyses of stomach contents, scats and regurgitates suggest a diet dominated by bony fish and squid, with cartilaginous species (e.g. sharks and rays) either absent or underrepresented because of a lack of preservable hard parts. Here we report on a subadult specimen from south-eastern Australia, which was found ashore emaciated and with numerous puncture wounds across its lips, cheeks, throat and the inside of its oral cavity. Fish spines embedded in the carcass revealed that these injuries were inflicted by chimaeras and myliobatiform rays (stingrays and relatives), which matches reports on the diet of A. forsteri from New Zealand, but not South Australia. Shaking and tearing of prey at the surface may help to avoid ingestion of the venomous spines, perhaps contributing to their absence from scats and regurgitates. Nevertheless, the number and severity of the facial stab wounds, some of which led to local necrosis, likely affected the animal's ability to feed, and may account for its death. Despite their detrimental effects, fish spine-related injuries are difficult to spot, and may be a common, albeit cryptic, type of trauma. We therefore recommend that stranded seals be systematically examined for this potentially life-threatening pathology.

Prodigious alcohol consumption by Australian rugby league footballers

As an incidental finding in a general 'life-style' survey, amateur rugby footballers were found to drink prodigious (12-24 schooners per session) quantities of beer. Such drinking was regarded by the players as part of the traditions of mateship associated with the game. The need for intervention is discussed.

Increased attendances of people of eastern European origin at sexual health services in London

OBJECTIVE

To describe the service use of migrants from eight central and eastern European (CEE) countries at two central London genitourinary medicine (GUM) clinics before and after accession to the European Union on 1 May 2004.

METHODS

KC60 data collected between 1 June 2001 and 30 April 2007. Data refer to new attendances and exclude those attending for follow-up appointments.

RESULTS

102,604 people attended the clinics at least once over the study period. Between May 2006 and 30 April 2007 individuals born in the eight CEE countries accounted for 7.9% of attendances among women and 2.5% of attendances made by men; the proportion increasing significantly over the 6-year study period (p<0.001). Syphilis was more likely in CEE men (age-adjusted odds ratio (OR) 2.98, 95% CI 1.07 to 8.29) and family planning services were more likely to be required for CEE women (23.9% vs 12.4%, age-adjusted OR 2.33, 95% CI 2.02 to 2.68, p<0.001), than for those born elsewhere. A larger proportion of men from CEE countries were recorded as homosexual or bisexual than men from other countries (38.3% vs 31.9%, p = 0.003).

CONCLUSIONS

CEE migrants already have a substantial impact on GUM services in London. If attendance rates continue at the current level CEE women will soon account for over 10% of new attendances. Although the majority of CEE migrants are men, proportionately fewer CEE men accessed GUM services than women. Sexual and reproductive health services need to adapt quickly to meet the needs of this growing population.

Functional analysis of CHX21: a putative sodium transporter in Arabidopsis

The functional role of CHX21, a member of the Arabidopsis thaliana CHX cation transporter family, has been investigated in plants growing under "ideal" conditions and in the presence of elevated NaCl levels. In public databases, AtCHX21 (At2g31910) is annotated as a putative Na+/H+ antiporter. In this study, Southern analysis was used to identify a genotype that contained a single transposon insertion within its genome; using PCR, this insertion was shown to be within the CHX21 locus. No CHX21 transcript was detectable in Atchx21 (mutant) plants using RT-PCR. In the absence of salt stress, Atchx21 showed significant quantitative differences from the wild type (AtCHX21) in development with respect to characters such as rosette width and flowering time. In the presence of 50 mM NaCl, (i) roots of Atchx21 elongated more slowly than the wild type, (ii) the leaf sap Na+ concentration was significantly lower in Atchx21 compared with the wild type, and (iii) the concentra) in the xylem was lower compared with the wild type. The concentration of Na+ exported from the leaf in the phloem was unchanged. Thus, loading of Na+ into the root xylem could explain changes in leaf concentration of Na+. This hypothesis was supported by immunolocalization which demonstrated that the AtCHX21 transporter could only be detected in root endodermal cells. Immunogold labelling of ultra-thin sections, followed by transmission electron microscopy, demonstrated the localization of the protein in the plasma membrane. The data demonstrate that the CHX21 transporter may play a role in regulation of xylem Na+ concentration and, consequently, Na+ accumulation in the leaf.

Interactions between proteins bound to biomembranes

We study a physical model for the interaction between general inclusions bound to fluid membranes that possess finite tension gamma, as well as the usual bending rigidity kappa. We are motivated by an interest in proteins bound to cell membranes that apply forces to these membranes, due to either entropic or direct chemical interactions. We find an exact analytic solution for the repulsive interaction between two similar circularly symmetric inclusions. This repulsion extends over length scales approximately sqrt[kappa/gamma] and contrasts with the membrane-mediated contact attraction for similar inclusions on tensionless membranes. For noncircularly symmetric inclusions we study the small, algebraically long-ranged, attractive contribution to the force that arises. We discuss the relevance of our results to biological phenomena, such as the budding of caveolae from cell membranes and the striations that are observed on their coats. These, and other, "gnarly buds" may prove fascinating to study further.

Confocal imaging, visualization and 3-D surface measurement of small mammalian teeth

The difficulties traditionally faced by functional morphologists in representing and interpreting three-dimensional objects can now be mostly overcome using available laser and computer imaging technologies. A practical method for three-dimensional imaging of small mammalian teeth using confocal microscopy is reported. Moulding and casting of the teeth were first performed, followed by confocal fluorescence imaging. Accuracy and precision of the scanned structures were tested in morphometric studies by using a new technique to measure the noise in the scan of a three-dimensional surface, and linear and angular dimensions of the scans were compared with measurements made using traditional morphological tools. It is shown that measurements can be taken with less than 4% difference from the original object. Teeth of the microchiropteran bat Chalinolobus gouldii were scanned and measured to show the potential of the techniques. Methods for visualizing the small teeth in three-dimensional space, and animating the teeth in occlusion, show the power of this approach in aiding a three-dimensional understanding of the structure and function of teeth and other three-dimensional structures.

Going APE over ref-1

The DNA base excision repair (BER) pathway is responsible for the repair of cellular alkylation and oxidative DNA damage. A crucial and the second step in the BER pathway involves the cleavage of baseless sites in DNA by an AP endonuclease. The major AP endonuclease in mammalian cells is Ape1/ref-1. Ape1/ref-1 is a multifunctional protein that is not only responsible for repair of AP sites, but also functions as a reduction-oxidation (redox) factor maintaining transcription factors in an active reduced state. Ape1/ref-1 has been shown to stimulate the DNA binding activity of numerous transcription factors that are involved in cancer promotion and progression such as Fos, Jun, NF(B, PAX, HIF-1(, HLF and p53. Ape1/ref-1 has also been implicated in the activation of bioreductive drugs which require reduction in order to be active and has been shown to interact with a subunit of the Ku antigen to act as a negative regulator of the parathyroid hormone promoter, as well as part of the HREBP transcription factor complex. Ape1/ref-1 levels have been found to be elevated in a number of cancers such as ovarian, cervical, prostate, rhabdomyosarcomas and germ cell tumors and correlated with the radiosensitivity of cervical cancers. In this review, we have attempted to try and assimilated as much data concerning Ape1/ref-1 and incorporate the rapidly growing information on Ape1/ref-1 in a wide variety of functions and systems.

Isoprostanes, novel eicosanoids that produce nociception and sensitize rat sensory neurons

Isoprostanes are a novel class of eicosanoids primarily formed by peroxidation of arachidonic acid. Because of their potential as inflammatory and/or hyperalgesic agents whose formation is largely independent of cyclooxygenases, we examined whether 8-iso prostaglandin E(2) (8-iso PGE(2)) or 8-iso prostaglandin F(2alpha) (8-iso PGF(2alpha)) reduces mechanical and thermal withdrawal threshold in rats, and whether they sensitize rat sensory neurons. Injection of 1 microg of 8-iso PGE(2) (in 2.5 microl) into the hindpaw of rats significantly reduced mechanical and thermal withdrawal thresholds, whereas 1 microg of 8-iso PGF(2alpha) elicited a transient decrease in only the mechanical withdrawal threshold. Both isoprostanes enhanced the firing of C-nociceptors in a concentration-dependent manner when injected into peripheral receptive fields. Exposing sensory neurons grown in culture to 1 microM 8-iso PGE(2) or 8-iso PGF(2alpha) augmented the number of action potentials elicited by a ramp of depolarizing current. In contrast, 8-iso PGE(2) but not 8-iso PGF(2alpha) enhanced the release of substance P- and calcitonin gene-related peptide-like immunoreactivity from isolated sensory neurons. Ten micromolar 8-iso PGE(2) stimulated peptide release directly, whereas treatment with 1 microM 8-iso PGE(2) augmented the release evoked by either bradykinin or capsaicin. Pretreating neuronal cultures with the nonsteroidal anti-inflammatory drug ketorolac did not alter the sensitizing action of 8-iso PGE(2) on peptide release, suggesting that this action of the isoprostane was not secondary to the production of prostaglandins via the cyclooxygenase pathway. These data support the notion that isoprostanes are an important class of inflammatory mediators that augment nociception.

The epidemiology of pediatric glaucoma: the Toronto experience

BACKGROUND

This study was conceived to provide an insight into the spectrum of glaucoma in the pediatric population. We also set out to compare the success of disease control and the prognosis for vision within the different diagnostic subgroups. This is the largest single population of children with glaucoma that has been so described and compared.

METHODS

The charts of children who were first seen between birth and age 16 years and who attended the Hospital for Sick Children with any form of glaucoma between January 1974 and January 1995 were reviewed and entered into the study.

RESULTS

Data are presented for 306 children. Congenital glaucoma was the most common subtype, accounting for 38%. Patients with congenital glaucoma were young, had surgery, and had more operations than any other group except those with aniridia. Goniotomy offered a cure in 47.8% of the patients. A bimodal distribution reflected their visual performance. Patients with aphakic glaucoma, the next most prevalent group (20%), presented at an older age (4.5 years). Surgical intervention was performed in 50% of these children. Nearly all patients with Sturge-Weber syndrome (80%) had surgery. The following glaucoma groups were associated with a poor visual outcome: aniridia, anterior segment developmental anomalies involving the cornea, uveitis with glaucoma other than steroid induced, retinopathy of prematurity, and persistent hyperplastic primary vitreous. Steroid-induced glaucoma and anterior segment dysgenesis, excluding Peters anomaly, had uniformly good outcomes.

CONCLUSION

The ability to control glaucoma in childhood and visual prognosis is highly variable. Particular diagnostic categories do consistently well and some do poorly.

The cAMP transduction cascade mediates the PGE2-induced inhibition of potassium currents in rat sensory neurones

1. The role of the cyclic AMP (cAMP) transduction cascade in mediating the prostaglandin E2 (PGE2)-induced decrease in potassium current (IK) was investigated in isolated embryonic rat sensory neurones using the whole-cell patch-clamp recording technique. 2. Exposure to 100 microM chlorophenylthio-adenosine cyclic 3', 5'-monophosphate (cpt-cAMP) or 1 microM PGE2 caused a slow suppression of the whole-cell IK by 34 and 36 %, respectively (measured after 20 min), without a shift in the voltage dependence of activation for this current. Neither of these agents altered the shape of the voltage-dependent inactivation curve indicating that the suppression of IK did not result from alterations in the inactivation properties. 3. To determine whether the PGE2-mediated suppression of IK depended on activation of the cAMP pathway, cells were exposed to this prostanoid in the presence of the protein kinase A (PKA) inhibitor, PKI. The PGE2-induced suppression of IK was prevented by PKI. In the absence of PGE2, PKI had no significant effect on the magnitude of IK. 4. Results obtained from protocols using different conditioning prepulse voltages indicated that the extent of cpt-cAMP- and PGE2-mediated suppression of IK was independent of the prepulse voltage. The subtraction of control and treated currents revealed that the cpt-cAMP- and PGE2-sensitive currents exhibited little time-dependent inactivation. Taken together, these results suggest that the modulated currents may be delayed rectifier-like IK. 5. Exposure to the inhibitors of IK, tetraethylammonium (TEA) or 4-aminopyridine (4-AP), reduced the control current elicited by a voltage step to +60 mV by 40-50 %. In the presence of 10 mM TEA, treatment with cpt-cAMP did not result in any further inhibition of IK. In contrast, cpt-cAMP reduced IK by an additional 25-30 % in the presence of 1 mM 4-AP. This effect was independent of the conditioning prepulse voltage. 6. These results establish that PGE2 inhibits an outward IK in sensory neurones via activation of PKA and are consistent with the idea that the PGE2-mediated sensitization of sensory neurones results, in part, from an inhibition of delayed rectifier-like IK.

Necrotising fasciitis as a complication of botulinum toxin injection

PURPOSE

To highlight the need for early diagnosis and treatment of the rare condition of necrotising fasciitis as a complication of botulinum toxin injection, and to illustrate that injections in immunocompromised patients carry a rare but serious risk.

RESULTS AND METHODS

A case report is presented of an 80-year-old woman suffering from blepharospasm and chronic myeloid leukaemia, who developed necrotising fasciitis 3 days after a botulinum toxin injection.

CONCLUSIONS

Chronic debilitating processes such as diabetes, alcoholism and polymyositis have been suggested as predisposing factors in the development of necrotising fasciitis. We believe this is the first reported case of necrotising fasciitis occurring secondary to a botulinum toxin injection. The fact that this infection extended through the fascial planes and led to the death of muscle was, probably, because an inoculum was introduced directly into the muscle at the time of botulinum toxin treatment. This may have led to its deep spread and difficulty in debriding the area. Chronic myeloid leukaemia does not in itself cause significant immunosuppression, but our patient was on anti-proliferative treatment and had a low leucocyte count, which may have been a predisposing factor in this case.

Prostaglandins suppress an outward potassium current in embryonic rat sensory neurons

The cellular mechanisms giving rise to the enhanced excitability induced by prostaglandin E2 (PGE2) and carba prostacyclin (CPGI2) in embryonic rat sensory neurons were investigated using the whole cell patch-clamp recording technique. Exposing sensory neurons to 1 microM PGE2 produced a twofold increase in the number of action potentials elicited by a ramp of depolarizing current, but this eicosanoid had no effect on the resting membrane potential or the amplitude of the slow afterhyperpolarization. Characterization of the outward potassium currents in the embryonic sensory neurons indicated that the composition of the total current was variable among these neurons. A steady-state inactivation protocol was used to determine the extent of residual noninactivating current. A conditioning prepulse to +20 mV demonstrated that some of these neurons exhibited only a sustained potassium current with little steady-state inactivation whereas other exhibited some combination of a sustained as well as a rapidly inactivating IA-type current. Treatment with 1 microM PGE2 or 1 microM CPGI2, but not 1 microM prostaglandin F2 alpha (PGF2 alpha) produced a time-dependent suppression of the total potassium current. After a 20-min exposure, PGE2 and CPGI2 inhibited the maximal current obtained at +60 mV by 48 and 40%, respectively. The prostaglandin-induced suppression of the potassium current was not associated with a shift in the voltage dependence for activation. Subtraction of the currents remaining after PGE2 or CPGI2 treatment from their respective control recordings revealed that the prostaglandin-sensitive current had characteristics that were consistent with a sustained-type of potassium current. This idea is supported by the following observation. The steady-state inactivation protocol revealed that for prepulse voltages activating both rapidly inactivating and sustained currents, the relaxation of the current was accelerated after treatment with PGE2 or CPGI2 suggesting the removal of a slower component. This effect was not observed in neurons exhibiting only the sustained type current. These results suggest that pro-inflammatory prostaglandins enhance the excitability of rat sensory neurons, in part, through the suppression of an outward potassium current that may modulate the firing threshold for generation of the action potential.

Differential regulation of evoked peptide release by voltage-sensitive calcium channels in rat sensory neurons

To determine whether the sensitizing action of prostaglandins on sensory neurons are due to modulation of voltage-sensitive calcium channels (VSCC) we examined the effects of inhibiting these channels on PGE2-induced enhancement of evoked peptide release from isolated dorsal root ganglion neurons. The inhibitory effects of the VSCC blockers on stimulated release were dependent upon the type of chemical agent used to evoke the release. Bradykinin-stimulated release of immunoreactive substance P (iSP) and calcitonin gene-related peptide (iCGRP) was attenuated by the N-type VSCC blocker, omega-conotoxin GVIA (100 nM), but was unaffected by blockade of L-type (1 microM nifedipine) or P-type (200 nM omega-agatoxin IVA) VSCC. In contrast, potassium-stimulated release of peptides was inhibited by nifedipine, but not by omega-conotoxin GVIA or omega-agatoxin IVA. None of the VSCC blockers tested attenuated capsaicin-stimulated release of iSP and iCGRP. The combination of 1 microM nifedipine and 100 nM omega-conotoxin GVIA reduced the whole cell calcium current 89% +/- 1.7%. Administration of 100 nM PGE2 potentiated bradykinin- and capsaicin-evoked peptide release by 2-3-fold. Neither nifedipine nor omega-conotoxin GVIA attenuated the PGE2-mediated potentiation of bradykinin-evoked release, and neither omega-conotoxin GVIA nor omega-agatoxin IVA blocked the potentiation of capsaicin-evoked release induced by PGE2. These results indicate that the sensitizing actions of PGE2 as measured by enhanced peptide release, are not mediated by L-, N-, or P-type VSCC.

Effects of vagal afferent nerve stimulation on noxious heat-evoked Fos-like immunoreactivity in the rat lumbar spinal cord

Electrophysiological and behavioral studies have described modulation of nociception by vagal afferent fibers. The objectives of this study were to 1) use Fos-like immunoreactivity as a marker for neuronal activity to examine populations of neurons in the spinal cord that are activated by a noxious heat stimulus, 2) determine whether heat-evoked Fos-like immunoreactivity can be modulated by vagal afferent stimulation, and 3) determine whether vagally-mediated effect on heat-evoked Fos-like immunoreactivity can be blocked by intrathecally administered serotoninergic receptor and alpha-adrenergic receptor antagonists. Neurons demonstrating Fos-like immunoreactivity were located in the ipsilateral superficial and deep dorsal horn laminae extending from the caudal L3 through the rostral L6 region of the spinal cord. Stimulation of the right cervical vagus nerve attenuated significantly (42%) heat-evoked Fos-like immunoreactivity in the superficial laminae. The reduction in Fos-like immunoreactivity by vagal stimulation was abolished by intrathecal administration of methysergide, a nonselective serotoninergic receptor antagonist, but not by phentolamine, a nonselective alpha-adrenoceptor antagonist. These results suggest that vagal afferent modulation of spinal nociceptive transmission is mediated, at least in part, by serotonin receptors.

Effects of anesthetic agents on somatosensory responses of raphespinal neurons in the cat

The goal of this study was to examine the effects of alpha-chloralose and pentobarbital on the somatosensory responses of medullary raphespinal neurons. With alpha-chloralose, 98% of neurons responded to innocuous stimuli, particularly tapping, but only 1/64 responded selectively to nociceptive stimuli. In contrast, 73% of neurons responded selectively to noxious stimuli with pentobarbital, and none responded selectively to innocuous stimuli. In addition, raphespinal neurons studied with pentobarbital had higher spontaneous discharge rates, and a higher incidence of spontaneity, than neurons studied with alpha-chloralose. Thus, different anesthetics produce raphespinal neurons with different somatosensory response characteristics.

Responses of medullary raphe neurons to electrical and chemical activation of vagal afferent nerve fibers

1. Various intensities, frequencies, and pulse widths of electrical stimulation of vagal afferent fibers were used to assess the responses of 87 medullary raphe neurons to vagal afferent fiber input in pentobarbital sodium-anesthetized, barodenervated paralyzed cats. Thirty-seven neurons were antidromically activated from the T2-T3 segments of the thoracic spinal cord, and 40 neurons could not be antidromically activated. Neurons were located in the nucleus raphe magnus (79%) and the nucleus raphe obscurus (15%). The remaining 6% of the neurons were not found; however, their locations were comparable in depth and position on the midline with other neurons in the same animals whose locations were identified. 2. The responses of 60 neurons to electrical stimulation of vagal afferent fibers were classified as excitatory (38%), inhibitory (24%), or mixed, (7%). The mixed responses were characterized by excitation at one frequency or intensity and inhibition at another frequency or intensity. The remaining 27 neurons did not clearly respond. 3. The excitatory responses to electrical stimulation of the cervical vagus nerve were intensity and frequency dependent. Inhibitory responses were frequency dependent at lower frequencies of stimulation and both frequency and intensity dependent at higher frequencies. The mixed responses were frequency dependent. Overall, longer pulse widths produced significantly greater responses than shorter pulse widths. 4. Thirty-three neurons were tested for responses to chemical stimulation of vagal afferents with intra-atrial injections of three doses of veratridine. Twenty-one percent were excited, 55% were inhibited, and 6% had mixed responses. For the mixed responses, excitation occurred at one dose and inhibition at another. The remaining 18% of the neurons were unresponsive to veratridine. The excitatory responses were dose dependent, but the inhibitory responses were not. Three doses of phenybiguanide (PBG) were also used to chemically activate vagal afferents in 27 neurons. Eleven percent were excited, 44% were inhibited, and 4% had mixed responses. The remaining 41% were unresponsive to PBG. The excitatory and inhibitory responses were dose dependent. 5. When comparing responses in projection and nonprojection neurons, inhibition was seen significantly more often in projection neurons and excitation in nonprojection neurons. Sixty-three percent of the neurons inhibited by electrical stimulation were raphespinal neurons, and 78% of the neurons excited by vagal stimulation were nonprojection neurons. Similar observations were made with the responses to chemical activation of the vagus. 6. Neurons with lower spontaneous discharge rates were more often excited by vagal stimulation and neurons with higher rates were more often inhibited.(ABSTRACT TRUNCATED AT 400 WORDS)

Responses of medullary raphespinal neurons to electrical stimulation of thoracic sympathetic afferents, vagal afferents, and to other sensory inputs in cats

1. Medullary raphespinal neurons antidromically activated from the T2-T5 segments were tested for responses to electrical stimulation of cervical vagal and thoracic sympathetic afferents (by stimulating the left stellate ganglion), somatic probing, auditory stimuli, and visual stimuli in cats anesthetized with alpha-chloralose. A total of 99 neurons in the raphe nuclei were studied; the locations of 76 cells were histologically confirmed. Neurons were located in raphe magnus (RM, 65%), raphe obscurus (RO, 32%), and raphe pallidus (RPa, 4%). The mean conduction velocity of these neurons was 62 +/- 2.9 (SE) m/s with a range of 1.1-121 m/s. 2. A total of 60/99 tested neurons responded to electrical stimulation of sympathetic afferents. Quantitation of responses was obtained for 55 neurons. With one exception, all responsive neurons were excited and exhibited an early burst of spikes with a mean latency of 16 +/- 1.2 ms. From a spontaneous discharge rate of 5.2 +/- 1.2 spikes/s, neuronal activity increased by 2.9 +/- 0.3 spikes/stimulus. In addition to an early peak, 15 neurons (25%) exhibited a late burst of spikes with a latency of 182 +/- 12.9 ms; neuronal activity increased by 5.0 +/- 1.3 spikes/stimulus. Duration of the late peak (130 +/- 18.5 ms) was longer than for the early peak (18 +/- 0.7 ms), but threshold voltages for eliciting each peak were comparable. Sixteen of 29 spontaneously active neurons exhibited a postexcitatory depression of activity that lasted for 163 +/- 19.1 ms. All but one tested neuron in RO responded to stimulation of sympathetic afferents, but 65% of neurons in RM responded to this stimulus. 3. In response to vagal afferent stimulation, 19% of 57 neurons exhibited inhibition only, 11% were only excited, and 9% were either excited or inhibited, depending on the stimulus paradigm used; the remaining 61% of neurons were unresponsive. From a spontaneous rate of 7.9 +/- 3.8 spikes/s, excited cells increased their discharge rate by 1.6 +/- 0.3 spikes/stimulus. Activity of inhibited cells was reduced from 21.3 +/- 5.8 to 7.8 +/- 3.1 spikes/s. The conditioning-test (CT) technique was used to assess 11 neurons' responses. Stellate ganglion stimulation was the test stimulus, and vagal stimulation the conditioning stimulus. Vagal stimulation reduced the neuronal responses to stellate ganglion stimulation by an average of 50% with a CT interval of 60-100 ms, and cell responses returned to control after 300 ms. With spontaneous cell activity, low frequencies of vagal stimulation were generally excitatory, and high frequencies (10-20 Hz) inhibitory.(ABSTRACT TRUNCATED AT 400 WORDS)

Responses of medullary raphespinal neurons to coronary artery occlusion, epicardial bradykinin, and cardiac mechanical stimuli in cats

1. A total of 59 medullary raphespinal neurons antidromically activated from the T2-T5 segments were tested for responses to coronary artery occlusion, epicardial application of bradykinin, and mechanical probing of the epicardium in cats anesthetized with alpha-chloralose. With the exception of five neurons, only those neurons that were responsive to electrical stimulation of the left stellate ganglion were tested for responses to these stimuli. Neurons in this study are a subset of those in the companion report. 2. Six neurons (12%) responded to epicardial bradykinin. Five cells were excited, and one was inhibited. Nine neurons (18%) had cardiac receptive fields, and one neuron (2%) had a field confined to the pericardium. 3. Neurons were tested for responses to separate occlusions of the left anterior descending (LAD) and circumflex (CX) coronary arteries. Overall, 13/34 (38%) of tested raphespinal neurons were responsive to coronary artery occlusion. Responses to coronary artery occlusion consisted of two major patterns. One pattern consisted of either an increase or decrease in neuronal firing rate after the heart became ischemic; this pattern was termed an ischemic (IS) response. Ten neurons (29%) exhibited an IS response to occlusion of the LAD and/or CX coronary arteries. Because four neurons exhibited IS responses to occlusion of each artery, there were a total of 14 IS responses. Of these, 10 were inhibitory, and 4 were excitatory. The second pattern of response consisted of a rapidly adapting excitation or inhibition at the onset or release of occlusion, but cell activity was unchanged during cardiac ischemia; this pattern was termed an onset (ON) response. Three neurons (9%) exhibited ON responses; two were excited, and one was inhibited. No neurons demonstrated both ON and IS responses during occlusion. 4. Twenty-one neurons were tested for responses to occlusion of each artery. Seventeen neurons (81%) exhibited similar patterns of responses to occlusion of each artery; that is, they either showed the same pattern of response to occlusion of each artery or they were unresponsive to either occlusion. For the 5 of these 17 neurons that were responsive, direction of change in neuronal activity (excitation or inhibition) was the same for occlusion of each artery. 5. All raphespinal neurons tested for responses to epicardial bradykinin and coronary artery occlusion were responsive to electrical stimulation of the left stellate ganglion. In addition, 16/28 (57%) of neurons tested for responses to occlusion were responsive to electrical stimulation of the right cervical vagus nerve.(ABSTRACT TRUNCATED AT 400 WORDS)

Heart rate variability before and after myocardial infarction in conscious dogs at high and low risk of sudden death

Heart rate variability has been demonstrated both experimentally and clinically to be of prognostic importance in determining mortality after myocardial infarction. However, no paired studies have been reported to examine heart rate variability before and after myocardial infarction. The hypothesis was tested that low values of heart rate variability provided risk assessment both before and after myocardial infarction with use of an established canine model of sudden cardiac death. Risk for sudden death was assessed 1 month after myocardial infarction by a protocol in which exercise and myocardial ischemia were combined; dogs that developed ventricular fibrillation were classified at high risk for sudden death (susceptible) and the survivors were considered low risk (resistant). In resistant dogs, myocardial infarction did not affect any measure of heart rate variability: 1) mean RR interval, 2) standard deviation of the mean RR interval, and 3) the coefficient of variance (standard deviation/RR interval). By contrast, after myocardial infarction, susceptible dogs showed significant decrease in all measures of heart rate variability. Before myocardial infarction, no differences were seen between susceptible and resistant dogs. However, 30 days after infarction, epidemiologic analysis of the coefficient of variance showed high sensitivity and specificity (88% and 80%, respectively), predicting susceptibility. Therefore, results of analysis of 30 min of beat to beat heart period at rest 30 days after myocardial infarction are highly predictive for increased risk of sudden death.

Retinal detachment and its relation to cataract surgery

In Western Australia during the period 1 January 1976 to 31 December 1987 1089 eyes of 1044 patients in hospital were operated upon for primary rhegmatogenous retinal detachment due to causes other than penetrating trauma. Of these eyes 295 (27%) were aphakic or pseudophakic. During this period the annual number of cataract operations in the State increased by a factor of 245%, while aphakic and pseudophakic retinal detachment operations rose by only 55%. The declining risk of retinal detachment following cataract surgery is attributed to improvements in microsurgical techniques. In 1983 and 1984 the incidence of aphakic and pseudophakic retinal detachments dropped significantly (p less than 0.05). At about this time extracapsular cataract surgery became widespread in the State, and this may explain the observed fall in retinal detachment operations. Since 1984 the incidence has risen owing to the rapidly increasing prevalence of pseudophakia in the resident population.

A study of the use of free-text fields within a computer medical records system

At present, the general practitioner considers any imposed rigidity or standardisation in his record keeping as an encroachment on his clinical practice. Thus, computerised clinical records are regarded with some suspicion. This paper explores the likely requirements of a computerised records system which will leave the clinician all his freedom, but at the same time give him all the potential advantages of a structured information gathering system. This investigation formed part of a joint project between IBM and the University of Sheffield Medical School, in conjunction with two general practices in the Sheffield area. The overall objective of the project was to investigate the requirements for computers in general practice, and develop an experimental GP computer system.

Primary pleural liposarcoma

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Results in children with local and regional neuroblastoma managed with and without vincristine, cyclophosphamide, and imidazolecarboxamide. A report from the Children's Cancer Study Group

Members of children's cancer study group designed Study CCG 351 to determine whether three drug chemotherapy improved the survival experience of children with localized neuroblastoma. Patients in stages I-III were treated with surgical removal of the primary tumor and those in stages II and III received radiation therapy to the tumor bed and chemotherapy. Treatment included cyclophosphamide, imidazolecarboxamide, and vincristine given in 5-day pulses each month for 12 courses. The results were compared to those from a previous study, CCG 011, for localized neuroblastoma, in which children were randomized between a treatment regimen that included cyclophosphamide and one with no chemotherapy. There were 133 evaluable patients, subdivided as follows: stages I-26, stages II-74, and stages III-33. The 3-year life-table survival rates by stage of 96, 89 and 50% were not significantly different from the patients in CCG 011 similarly staged who received either no chemotherapy or oral CPM. These data suggest that multiagent chemotherapy, as prescribed, did not improve the outlook for children with locally advanced but nonmetastatic neuroblastoma. The staging criteria employed showed a modest difference in outcome between patients in stages I and II, but a significant poorer survival for stage III as compared to either stage I or II.

A small cluster of Hodgkin's disease

Nine cases of Hodgkin's disease and one of acute lymphoblastic leukaemia occurred in 1972-5 in an area of less than 1 km. Clinical, social, and drug histories provided no relevant information, and definite patient-to-patient contacts before the onset of disease were not established. There was a higher incidence of malignant neoplasms in first-degree relatives of the patients than in those of a small control group living in the same area. There was no apparent reason for this cluster of cases, but geographical, climatic, and entomological studies are being carried out.

The use of sodium valproate in a case of status epilepticus

A child in status epilepticus, who did not respond to intravenous diazepam, was treated with sodium valproate by naso-gastric tube. Subsequent clinical and encephalographic improvement appeared to be related to the sodium valproate, and its value in cases of status epilepticus is discussed.