Pten and p53 converge on c-Myc to control differentiation, self-renewal, and transformation of normal and neoplastic stem cells in glioblastoma.

Glioblastoma (GBM) is a highly lethal primary brain cancer with hallmark features of diffuse invasion, intense apoptosis resistance and florid necrosis, robust angiogenesis, and an immature profile with developmental plasticity. In the course of assessing the developmental consequences of central nervous system (CNS)-specific deletion of p53 and Pten, we observed a penetrant acute-onset malignant glioma phenotype with striking clinical, pathological, and molecular resemblance to primary GBM in humans. This primary, as opposed to secondary, GBM presentation in the mouse prompted genetic analysis of human primary GBM samples that revealed combined p53 and Pten mutations as the most common tumor suppressor defects in primary GBM. On the mechanistic level, the "multiforme" histopathological presentation and immature differentiation marker profile of the murine tumors motivated transcriptomic promoter-binding element and functional studies of neural stem cells (NSCs), which revealed that dual, but not singular, inactivation of p53 and Pten promotes cellular c-Myc activation. This increased c-Myc activity is associated not only with impaired differentiation, enhanced self-renewal capacity of NSCs, and tumor-initiating cells (TICs), but also with maintenance of TIC tumorigenic potential. Together, these murine studies have provided a highly faithful model of primary GBM, revealed a common tumor suppressor mutational pattern in human disease, and established c-Myc as a key component of p53 and Pten cooperative actions in the regulation of normal and malignant stem/progenitor cell differentiation, self-renewal, and tumorigenic potential.

Medical record review of deaths, unexpected intensive care unit admissions, and clinician referrals: detection of adverse events and insight into the system.

AIMS AND METHODS: To determine whether a programme of continuous medical record review of deaths, unexpected intensive care unit (ICU) admissions, and admissions referred by medical and nursing staff for specific review, would provide a range of adverse events from which to gain insight into the healthcare system of a large paediatric referral hospital. A quality assurance programme was commenced in 1996. RESULTS: Over a six year period there were 103 255 admissions; 1612 (1.6%) records were reviewed, from which 325 adverse events were detected. Events were associated with operations, procedures and anaesthesia (56.5%), diagnosis and therapy (24%), drug and fluid management (12.6%), and system issues (7%). Medical records were reviewed from 23 of the 28 clinical units. Review of the records and analysis of the adverse events triggered many system changes. CONCLUSIONS: The findings suggest that continuous medical record review may be a valuable method for the detection of adverse events and identifying system issues in children's hospitals.

Sickness, healing, and opera: Wagner's Parsifal.

Richard Wagner's opera Parsifal is examined as a study in illness, pain and healing. Wagner's intention was to communicate directly to the audience the "emotional content" of the suffering of the character Amfortas. This presentation of suffering allows us to take from the opera some general ideas about the nature of illness and healing and their metaphorical representation in art. Further insights can be gained from the genre of classical tragic drama, of which Parsifal is a modern example.

Mechanisms of cocaine-induced decreases in immune cell function.

Cocaine has previously been shown to decrease mitogen-induced T lymphocyte proliferation in rats following intravenous administration. However, in this report, it is demonstrated that central administration of cocaine (1-50 microg) had no effect on lymphocyte proliferation responses. Similarly, the quaternary derivative, cocaine methiodide, also suppressed lymphocyte proliferation only when administered peripherally (6.5 mg/kg), and not centrally (1-20 microg). These results suggest that the effects of cocaine were mediated through a peripheral mechanism. Since significant elevations in plasma corticosterone were observed with all routes of administration of cocaine, the effects of cocaine did not appear to be due entirely to activation of the HPA axis. Instead, the peripheral administration of the local anesthetic, lidocaine (5 mg/kg) or the monoamine reuptake inhibitor, RTI-55 (2-5 mg/kg), produced significant suppressive effects on proliferation. suggesting that both of these peripheral activities of cocaine may be involved in the alteration of lymphocyte responses.

Periplasmic superoxide dismutase in meningococcal pathogenicity.

Meningococcal sodC encodes periplasmic copper- and zinc-cofactored superoxide dismutase (Cu,Zn SOD) which catalyzes the conversion of the superoxide radical anion to hydrogen peroxide, preventing a sequence of reactions leading to production of toxic hydroxyl free radicals. From its periplasmic location, Cu,Zn SOD was inferred to acquire its substrate from outside the bacterial cell and was speculated to play a role in preserving meningococci from the action of microbicidal oxygen free radicals produced in the context of host defense. A sodC mutant was constructed by allelic exchange and was used to investigate the role of Cu,Zn SOD in pathogenicity. Wild-type and mutant meningococci grew at comparable rates and survived equally long in aerobic liquid culture. The mutant showed no increased sensitivity to paraquat, which generates superoxide within the cytosol, but was approximately 1,000-fold more sensitive to the toxicity of superoxide generated in solution by the xanthine/xanthine oxidase system. These data support a role for meningococcal Cu,Zn SOD in protection against exogenous superoxide. In experiments to translate this into a role in pathogenicity, wild-type and mutant organisms were used in an intraperitoneal mouse infection model. The sodC mutant was significantly less virulent. We conclude that periplasmic Cu,Zn SOD contributes to the virulence of Neisseria meningitidis, most likely by reducing the effectiveness of toxic oxygen host defenses.

Nocturnal polyuria and antidiuretic hormone levels in spinal cord injury.

OBJECTIVE: To establish baseline ADH levels in spinal cord injury patients and to evaluate whether spinal cord patients have attenuation of diurnal variation of ADH similar to children with enuresis and elderly with nocturnal polyuria. DESIGN: Twenty-seven healthy quadriplegic patients, ASIA impairment scale A, were evaluated for serum ADH levels at night and during the day. MAIN OUTCOME MEASURES: Evaluation of whether bladder overdistention caused by attenuation of diurnal variation of ADH is responsible for the episodes of autonomic dysreflexia and recurrent urinary tract infections in spinal cord injury patients who are on intermittent catheterization for bladder management. RESULTS: A lack of diurnal variation of ADH in the subject population. CONCLUSIONS: A trial of desaminocystein-D-arginine vasopressin (DDAVP) should be considered for patients with established attenuation of the diurnal variation ADH.

The minimum alveolar concentration (MAC) of sevoflurane with and without nitrous oxide in elderly versus young adults.

STUDY OBJECTIVE: To determine the minimum alveolar concentration (MAC) of sevoflurane with and without 65% nitrous oxide (N2O) in non-Asian patients at least 70 years of age, and in patients aged 18 to 35 years. DESIGN: Randomized open-study design. The Dixon up-down method determined the target sevoflurane concentration for each patient. SETTING: Operating rooms of a large university hospital. PATIENTS: 27 ASA status I and II patients aged 18 to 35 years and 26 patients at least 70 years of age, who were free of any conditions or diseases that would interfere with MAC determination. INTERVENTIONS: Unpremedicated patients breathed sevoflurane until the predetermined target end-tidal sevoflurane concentration was reached for at least 15 minutes before skin incision. Up-down sevoflurane increments were 0.25% after an initial target concentration of 2%. This continued until there were at least three crossover pairs in each of the four groups. MEASUREMENTS AND MAIN RESULTS: Patients were observed for purposeful movement in response to a skin incision. End-tidal sevoflurane, N2O and oxygen (O2) concentrations were measured by a calibrated infrared analyzer. MAC was determined by logistic regression analysis. The MAC of sevoflurane in O2/air for the mean age in each group was 2.6% in the younger group (age = 25 yr) and 1.45% in the elderly group (age = 76 yr). Nitrous oxide 65% decreased MAC about 50% in each group at any age studied. CONCLUSIONS: The MAC of sevoflurane determined in this study is similar to that determined in previous studies, including the MAC determined in an elderly Asian population. Increasing age and N2O decrease sevoflurane MAC similarly to that determined with other volatile anesthetics.

Cloning and molecular analysis of the Isi1 (rfaF) gene of Neisseria meningitidis which encodes a heptosyl-2-transferase involved in LPS biosynthesis: evaluation of surface exposed carbohydrates in LPS mediated toxicity for human endothelial cells.

Neisseria meningitidis, but not Haemophilus influenzae, damage cultured human endothelial cells. We have undertaken a study to generate genetically and structurally defined lipopolysaccharide (LPS) mutant strains of meningococci for functional studies to assess the role of surface exposed oligosaccharides in imparting specificity of toxic damage to human endothelial cells. The Isi1 gene, which had been shown to be involved in LPS biosynthesis of Neisseria gonorrhoeae, was amplified by PCR and cloned. Nucleotide sequence analysis confirmed the identity of the clone and revealed homology with Isi1 of N. gonorrhoeae and the rfaF gene of Salmonella typhimurium which encodes a heptosyl-2-transferase involved in LPS biosynthesis. The identity of the cloned Isi1 gene, as a functional rfaF homologue, was confirmed by the complementation of a S. typhimurium rfaF mutant using a P22 phage sensitivity test. An Isi1 mutant meningococcal strain was constructed, and structural analysis of the mutant LPS molecule revealed a single heptose in the core structure, consistent with a heptosyl-2-transferase deficient mutant. In order to investigate the relative cytotoxicities of meningococci expressing native and altered LPS, wild type, Isi1, and galE strains were compared in cytotoxicity assays using human umbilical vein endothelial cells (Huvecs) in culture. Analysis using Huvecs derived from several individuals (cords) showed that the three phenotypes were almost equally cytotoxic. Removal of the terminal portion (galE mutant) or the majority (Isi mutant) of the oligosaccharide did not effect LPS-mediated cytopathic damage to Huvecs in a culture suggesting that the oligosaccharide portion did not play a major role in cytotoxicity.

Investigations into the molecular basis of meningococcal toxicity for human endothelial and epithelial cells: the synergistic effect of LPS and pili.

Using human umbilical vein endothelial cells as an in vitro model of toxicity, it was found that Neisseria meningitidis, Neisseria gonorrhoeae, Neisseria lactamica and Neisseria sicca caused damage to these cells, in contrast to the lack of cytotoxicity exhibited by Haemophilus influenzae type b. N. meningitidis was also found to be toxic for human epithelial cells. The major toxic factor of N. meningitidis was found to be a heat-stable component of outer membrane vesicles, and could be inhibited by polymyxin B, suggesting that lipopolysaccharide plays a major role in toxicity. However, the toxicity mediated by lipopolysaccharide was modulated significantly by pilus-dependent adherence. Intra-strain variants expressing altered pilins which exhibited different levels of adherence to epithelial and endothelial cells were used to study the role of pilus. The degree of toxicity observed correlated with their relative level of adherence to cultured cells. In contrast, Opc-dependent increased adherence did not result in increased toxicity for endothelial cells, suggesting that pili have a synergistic effect, contributing to the overall damage.

A comparison of the effectiveness of Therevac SB and bisacodyl suppositories in SCI patients' bowel programs.

The evaluation described in this article compared the Therevac SB "mini-enema" with bisacodyl suppositories in the bowel management programs of patients with spinal cord injury (SCI). Of particular interest were (a) determining whether the additional costs of Therevac SB could be justified and (b) identifying the degree of bowel program improvement possible. Fourteen SCI patients were selected from the SCI inpatient unit and the clinic of a Department of Veterans Affairs facility. All patients experienced a delay of at least 45 minutes between insertion of a suppository and the beginning of stool evacuation. Each patient used bisacodyl suppositories for five bowel programs, then Therevac SB for five programs, finally repeating the bisacodyl suppositories for five more programs. Each patient maintained a bowel program log. Ten patients completed the evaluation. Using a MANOVA, the authors found a significant difference between bisacodyl and Therevac SB mean evacuation times for this group. An analysis of direct and indirect costs related to bowel care with the two regimens is also presented.

Effects of patient age on postorthodontic stability in Class II, division 1 malocclusions.

The increase in the proportion of adults in the typical orthodontic practice merits closer scrutiny of the treatment differences involved in adult vis-à-vis adolescent patients. Orthodontic treatment in the adolescent relies heavily on growth; in the adult, the practitioner must reposition teeth within the nongrowing arches. This difference may create the potential for greater postretention relapse in the adult; alternatively, continued growth in the subadult might detract from stability of the case. Two samples of Class II, Division 1 cases, all treated by one specialist, were examined an average of 5 years out of treatment. One group had been treated during adolescence (approximately 12 years of age), the other in adulthood (approximately 28 years). The orthodontic corrections were stable in both groups, but for different reasons: Posttreatment changes in the bony and dental structures of the adults were minimal. Bony changes (i.e., continued midface and mandibular growth) were appreciable in adolescents, and this growth--notably growth of the mandible--compensated for unfavorable drift of the dental elements (primarily mesial shift of the maxillary molar) after treatment. In sum, orthodontic corrections in adults were found to be at least as stable as those in the conventional adolescent patient.

Flumazenil reversal of midazolam sedation in the elderly.

In a randomized, double-blind, placebo-controlled study, the efficacy of flumazenil in reversing the psychomotor, sedative, and amnestic effects of midazolam in elderly patients after surgery under regional anesthesia was examined. Thirty ASA I-III patients older than 63 years undergoing regional anesthesia with midazolam sedation were randomly assigned to receive either intravenous flumazenil (n = 19) or intravenous placebo (n = 11) after surgery. After assessments of sedation immediately postoperatively, 0.1 mg/ml flumazenil or placebo was given in 2-ml increments twice, a minute apart, and titrated in further 2-ml increments until patients were awake or until 10 ml had been given. Efficacy of reversal was determined using patient and observer assessments of sedation and simple psychomotor tests administered preoperatively and at five, 15, 30, 60, 120, and 180 minutes after test drug administration. Reversal of amnesia was tested by assessing recall of pictures shown at five, 15, 30, and 60 minutes after drug administration. Time profiles of digit substitution test and observer assessment of sedation data were significantly different between the flumazenil and placebo groups. For observer's assessment of sleep, significant differences were noted between flumazenil and placebo groups only at five, 15, and 30 minutes after test drug administration. A significant difference was noted between flumazenil and placebo patients in the ability to recall pictures shown five and 15 minutes after drug administration, but not pictures shown at 30 or 60 minutes. Within-group analysis demonstrated that loss of difference over time between flumazenil and placebo groups was the result of decreasing effect of both flumazenil and midazolam.

Autonomic dysreflexia: a nursing challenge in the care of the patient with a spinal cord injury.

Autonomic dysreflexia is an emergency condition resulting in sudden severe hypertension that can occur in spinal cord injury (SCI) patients above the T-5-6 level. This hypertension has its proximate cause in neurologic, not cardiovascular, mechanisms. Knowledge about pathophysiology, possible consequences, and signs and symptoms will assist the nurse in identifying this syndrome, locating and removing causes, controlling symptoms, and preventing morbidity or mortality. A case study is used to illustrate a typical autonomic dysreflexia episode in a hospitalized patient at risk. Prevention of autonomic dysreflexia and patient and professional education are also addressed.

A clinical catheter for continuous blood gas measurement by mass spectrometry.

A new Teflon catheter for continuous in vivo measurement of blood gases by mass spectrometry has an outer diameter of 0.032 in. and can be inserted through percutaneous puncture with an 18-gauge needle. Response time (63% of a total change) is 40 s for oxygen and 65 s for carbon dioxide. When calibrated in analyzed gas at 37 degrees C, the catheter-mass spectrometer system has been shown to analyze tonometered blood with an error of 1.6% for oxygen and 1.9% for carbon dioxide. Temperature dependence is 2.0% per degrees C for oxygen and 1.6% per degrees C for carbon dioxide. The catheter was thrombo-resistant during in vivo use in seven dogs and measurements compared favorably with results of blood sample analyses by standard hospital methods. Compared with previous devices, the new catheter provides size and convenience, advantages that make it more applicable for routine clinical use.