Epigenetic Mechanisms Histone Deacetylase-Dependent Regulate the Glioblastoma Angiogenic Matrisome and Disrupt Endothelial Cell Behavior In Vitro

Glioblastoma (GBM) is the most aggressive brain tumor and different efforts have been employed in the search for new drugs and therapeutic protocols for GBM. Epitranscriptomics has shed light on new druggable Epigenetic therapies specifically designed to modulate GBM biology and behavior such as Histone Deacetylase inhibitors (iHDAC). Although the effects of iHDAC on GBM have been largely explored, there is a lack of information on the underlaying mechanisms HDAC-dependent that modulate the repertoire of GBM secreted molecules focusing on the set of Extracellular Matrix (ECM) associated proteins, the Matrisome, that may impact the surrounding tumor microenvironment. To acquire a better comprehension of the impacts of HDAC activity on the GBM Matrisome, we studied the alterations on the Matrisome-associated ECM regulators, Core Matrisome ECM glycoproteins, ECM-affiliated proteins and Proteoglycans upon HDAC inhibition in vitro as well as their relationship with glioma pathophysiological/clinical features and angiogenesis. For this, U87MG GBM cells were treated for with iHDAC or vehicle (control) and the whole secretome was processed by Mass Spectrometry NANOLC-MS/MS. In silico analyses revealed that proteins associated to the Angiogenic Matrisome (AngioMatrix), including Decorin, ADAM10, ADAM12 and ADAM15 were differentially regulated in iHDAC versus control secretome. Interestingly, genes coding for the Matrisome proteins differentially regulated were found mutated in patients and were correlated to glioma pathophysiological/clinical features. In vitro functional assays, using HBMEC endothelial cells exposed to the secretome of control or iHDAC treated GBM cells, coupled to 2D and 3D GBM cell culture system, showed impaired migratory capacity of endothelial cells and disrupted tubulogenesis in a Fibronectin and VEGF independent fashion. Collectively, our study provides understanding of epigenetic mechanisms HDAC-dependent to key Matrisomal proteins that may contribute to identify new druggable Epigenetic therapies or gliomagenesis biomarkers with relevant implications to improve therapeutic protocols for this malignancy.

Social association predicts immunological similarity in rewilded mice

Environmental influences on immune phenotypes are well-documented, but our understanding of which elements of the environment affect immune systems, and how, remains vague. Behaviors, including socializing with others, are central to an individual's interaction with its environment. We tracked behavior of rewilded laboratory mice of three inbred strains in outdoor enclosures and examined contributions of behavior, including social associations, to immune phenotypes. We found that the more associated two individuals were, the more similar their immune phenotypes were. Social association was particularly predictive of similar memory T and B cell profiles and was more influential than sibling relationships or worm infection status. These results highlight the importance of social networks for immune phenotype and reveal important immunological correlates of social life.

Automated healthcare-associated infection surveillance using an artificial intelligence algorithm

Healthcare-associated infections (HAIs) are among the most common adverse events in hospitals. We used artificial intelligence (AI) algorithms for infection surveillance in a cohort study. The model correctly detected 67 out of 73 patients with HAIs. The final model used a multilayer perceptron neural network achieving an area under receiver operating curve (AUROC) of 90.27%; specificity of 78.86%; sensitivity of 88.57%. Respiratory infections had the best results (AUROC ≥93.47%). The AI algorithm could identify most HAIs. AI is a feasible method for HAI surveillance, has the potential to save time, promote accurate hospital-wide surveillance, and improve infection prevention performance.

O-GlcNAcylation protein disruption by Thiamet G promotes changes on the GBM U87-MG cells secretome molecular signature

Glioblastoma (GBM) is a grade IV glioma highly aggressive and refractory to the therapeutic approaches currently in use. O-GlcNAcylation plays a key role for tumor aggressiveness and progression in different types of cancer; however, experimental evidence of its involvement in GBM are still lacking. Here, we show that O-GlcNAcylation plays a critical role in maintaining the composition of the GBM secretome, whereas inhibition of OGA activity disrupts the intercellular signaling via microvesicles. Using a label-free quantitative proteomics methodology, we identified 51 proteins in the GBM secretome whose abundance was significantly altered by activity inhibition of O-GlcNAcase (iOGA). Among these proteins, we observed that proteins related to proteasome activity and to regulation of immune response in the tumor microenvironment were consistently downregulated in GBM cells upon iOGA. While the proteins IGFBP3, IL-6 and HSPA5 were downregulated in GBM iOGA cells, the protein SQSTM1/p62 was exclusively found in GBM cells under iOGA. These findings were in line with literature evidence on the role of p62/IL-6 signaling axis in suppressing tumor aggressiveness and our experimental evidence showing a decrease in radioresistance potential of these cells. Taken together, our findings provide evidence that OGA activity may regulate the p62 and IL-6 abundance in the GBM secretome. We propose that the assessment of tumor status from the main proteins present in its secretome may contribute to the advancement of diagnostic, prognostic and even therapeutic tools to approach this relevant malignancy.

Summarising published results from spirometric surveys of COPD: the problem of inconsistent definitions

SETTING

The use of different spirometric definitions for chronic obstructive pulmonary disease (COPD) has made an informative review of the available prevalence surveys impossible.

OBJECTIVE

To derive adjustment factors that allow the comparison of studies using different spirometric criteria.

METHODS

Pre- and post-bronchodilator one-second forced expiratory volume (FEV1) and forced vital capacity (FVC) values were taken from the Burden of Obstructive Lung Disease (BOLD) survey in 16 centres. Using a post-bronchodilator FEV1/FVC ratio less than the lower limit of normal (LLN) as our reference prevalence, we calculated simple multiplicative adjustments to transform other reported prevalence estimates to reference values. These adjustments were then tested on independent data sets from six further BOLD centres and five centres from the PLATINO study, a Latin American survey on obstructive lung disease.

RESULTS

Prevalence estimates based on pre-bronchodilator fixed-ratio measurements were 5-25% higher than reference values, and were strongly positively biased with age and prevalence level. Applying simple adjustments provided prevalence estimates that were almost unbiased and within 5% of the reference values.

CONCLUSIONS

Using the BOLD data, we have been able to estimate COPD prevalences based on post-bronchodilator FEV1/FVC < LLN by adjusting estimates based on other common definitions, enabling more meaningful comparisons of published findings.

ADHD in DSM-5: a field trial in a large, representative sample of 18- to 19-year-old adults

BACKGROUND

The DSM criteria for adult attention-deficit/hyperactivity disorder (ADHD) have not been tested in American Psychiatric Association (APA) field trials for either DSM-IV or DSM-5. This study aimed to assess: (a) the prevalence of ADHD according to DSM-5 criteria; (b) the factor solution that provides the best fit for ADHD symptoms; (c) the symptoms with the highest predictive value for clinical impairment; and (d) the best symptomatic threshold for each ADHD dimension (inattention and hyperactivity/impulsivity).

METHOD

Trained psychologists evaluated 4000 young adults from the 1993 Pelotas Birth Cohort Study with an instrument covering all DSM-5 ADHD criteria. A series of confirmatory factor analyses (CFAs) tested the best factor structure. Complex logistic regressions assessed differential contributions of each symptom to clinical impairment. Receiver-operating characteristic (ROC) analyses tested which would be the best symptomatic cut-off in the number of symptoms for predicting impairment.

RESULTS

The prevalence of DSM-5 ADHD was 3.55% [95% confidence interval (CI) 2.98-4.12]. The estimated prevalence of DSM-IV ADHD was 2.8%. CFA revealed that a bifactor model with a single general factor and two specific factors provided the best fit for DSM-5 symptoms. Inattentive symptoms continued to be the most important predictors of impairment in adults. The best cut-offs were five symptoms of inattention and four symptoms of hyperactivity/impulsivity.

CONCLUSIONS

Our results, combined with previous findings, suggest a 27% increase in the expected prevalence of ADHD among young adults, comparing DSM-IV to DSM-5 criteria. The DSM-5 symptomatic organization derived a similar factor structure for adults as DSM-IV symptoms. Data using DSM-5 criteria support lowering the symptomatic threshold for diagnosing ADHD in adults.

Multifractal detrended fluctuation analysis to characterize phase couplings in seahorse (Hippocampus kuda) feeding clicks

Nonlinear phenomena in animal vocalizations fundamentally includes known features, namely, frequency jump, subharmonics, biphonation, and deterministic chaos. In the present study, the multifractal detrended fluctuation analysis (MFDFA) has been employed to characterize the phase couplings revealed in the feeding clicks of Hippocampus kuda yellow seahorse. The fluctuation function Fq(s), generalized Hurst exponent h(q), multifractal scaling exponent τ(q), and the multifractal spectrum f(α) calculated in the procedure followed were analyzed to comprehend the underlying nonlinearities in the seahorse clicks. The analyses carried out reveal long-range power-law correlation properties in the data, substantiating the multifractal behavior. The resulting h(q) spectrum exhibits a distinct characteristic pattern in relation to the seahorse sex and size, and reveals a spectral blind spot in the data that was not possible to detect by conventional spectral analyses. The corresponding multifractal spectrum related width parameter Δh(q) is well clustered, defining the individual seahorse clicks. The highest degree of multifractality is evident in the 18 cm male seahorse, signifying greater heterogeneity. A further comparison between the seahorse body size and weight (wet) with respect to the width parameter Δh(q) and the second-order Hurst exponent h(q=2) underscores the versatility of MFDFA as a robust statistical tool to analyze bioacoustic observations.

Adherence to the 2011 American Gastroenterological Association medical position statement for the diagnosis and management of Barrett's esophagus

Considerable variability exists in adherence to practice guidelines for Barrett's esophagus (BE). Rapid advances in management approaches to BE led to a new American Gastroenterological Association (AGA) medical position statement in 2011. Our aim was to assess how well members of the AGA Clinical Practice section adhered to these guidelines. A self-administered survey incorporating questions on diagnostic criteria, cancer risk estimates, screening, surveillance, and therapeutics for BE was distributed electronically to 5850 North American members of the AGA Clinical Practice section. The response rate was 470 of 2040 opened e-mails (23%). Intestinal metaplasia was required for diagnosis of BE by 90%, but the Prague classification was used by only 53% of those aware of it. The annual risk of progression to esophageal adenocarcinoma was reported as 0.1-0.5% by 76%. Screening practices were variable, with 35% screening all patients with chronic gastroesophageal reflux disease and 15% repeating endoscopy in patients with gastroesophageal reflux disease following a negative screening. Surveillance guidelines were followed by 79% for nondysplastic BE and 86% for low-grade dysplasia, with expert pathology confirmation of dysplasia reported by 86%. Proton pump inhibitor dosing was variable, with 18% administering twice-daily doses and 30% titrating dose to symptoms. Ablation therapy was recommended by 6% for nondysplastic BE, 38% for low-grade dysplasia, and 52% for high-grade dysplasia. There is satisfactory adherence to the new AGA guidelines with respect to diagnosis, cancer risk estimates, and surveillance intervals in a select group of respondents. However, adherence continues to be variable in the use of the Prague classification, screening, and dosing of antisecretory therapy. Use of ablation therapy increases with grade of dysplasia. The reason for continued variability in adherence to BE practice guidelines remains unclear, and more evidence-based guidance is required to enhance clinical practice.

Giardia duodenalis: genotypic comparison between a human and a canine isolates

INTRODUCTION

Evidence suggests that giardiasis is a zoonotic disease. The present work aimed to evaluate the genetic identity of Giardia duodenalis isolated from human and dog fecal samples from Belo Horizonte.

METHODS

Human and dog fecal samples were cultured for isolation of G. duodenalis. To determine the genotype of the isolates, primers that amplify a specific region in rRNA of the protozoan were used.

RESULTS

Two G. duodenalis isolates were obtained, which belong to the subgroup A genotype.

CONCLUSIONS

These findings suggest that the transmission of giardiasis follows a zoonotic pattern.

Comparing the performance of rat lungs preserved for 6 or 12 hours after perfusion with low-potassium dextran or histidine-tryptophan-ketoglutarate

INTRODUCTION

In lung transplantation, graft dysfunction is a frequent cause of mortality; the etiopathogenesis is related to ischemia-reperfusion injury. We sought to compare the lung performance of rats after reperfusion after presentation with 3 solutions at 2 ischemia times.

METHODS

We randomized 60 male Wistar rats to undergo anterograde perfusion via the pulmonary artery with low-potassium dextran (LPD), histidine-tryptophan ketoglutarate (HTK), or saline. After extraction, the heart-lung blocks were preserved in a solution at hypothermia for 6 or 12 hours before perfusion with homologous blood for 60 minutes using ex vivo system Isolated Perfused Rat or Guinea Pig Lung System (Harvard Apparatus). Respiratory mechanics, pulmonary weight, pulmonary artery pressure (PAP), and relative lung oxygenation capacity (ROC) measurements were obtained every 10 minutes.

RESULTS

Comparing tidal volume (TV), compliance, resistance, ROC, PAP, and pulmonary weight the LPD, HTK, and saline group did not differ at 6 and 12 hours. The TV was higher in the lungs with 6-hour ischemia in the LPD, HTK, and saline groups. Compliance was higher in the lungs with 6-hour ischemia in the LPD and saline groups. There were no differences in ROC values comparing lungs with 6- versus 12-hour ischemia in the LPD group. A significant difference was observed between lungs in the HTK and saline groups. Resistance was higher in the lungs with 12-hour ischemia among the LPD, HTK, and saline groups. There was a gradual weight increase in the lungs, particularly those undergoing 12-hour ischemia, despite the absence of a significant difference between groups.

CONCLUSION

Rat lungs perfused with LPD and HTK preservation solutions showed similar reperfusion performances in this ex-vivo perfusion model.

Alcohol and tobacco, and the risk of cancers of the upper aerodigestive tract in Latin America: a case-control study

BACKGROUND

Cancers of the upper aerodigestive tract (UADT; including oral cavity, pharynx, larynx and oesophagus) have high incidence rates all over the world, and they are especially frequent in some parts of Latin America. However, the data on the role of the major risk factors in these areas are still limited.

METHODS

We have evaluated the role of alcohol and tobacco consumption, based on 2,252 upper aerodigestive squamous-cell carcinoma cases and 1,707 controls from seven centres in Brazil, Argentina, and Cuba.

RESULTS

We show that alcohol drinkers have a risk of UADT cancers that is up to five times higher than that of never-drinkers. A very strong effect of aperitifs and spirits as compared to other alcohol types was observed, with the ORs reaching 12.76 (CI 5.37-30.32) for oesophagus. Tobacco smokers were up to six times more likely to develop aerodigestive cancers than never-smokers, with the ORs reaching 11.14 (7.72-16.08) among current smokers for hypopharynx and larynx cancer. There was a trend for a decrease in risk after quitting alcohol drinking or tobacco smoking for all sites. The interactive effect of alcohol and tobacco was more than multiplicative. In this study, 65% of all UADT cases were attributable to a combined effect of alcohol and tobacco use.

CONCLUSIONS

In this largest study on UADT cancer in Latin America, we have shown for the first time that a prevailing majority of UADT cancer cases is due to a combined effect of alcohol and tobacco use and could be prevented by quitting the use of either of these two agents.

[Smoking time evolution among medical students, 1986, 1991, 1996]

OBJECTIVE

To evaluate trends in smoking habits among medical students in the last ten years.

METHODS

In 1996, a cross-sectional survey of smoking habits was carried out among students in the first to the fifth year of medical school. Four hundred and nine students answered the questionnaire. A regular smoker was defined as someone who smokes one or more cigarettes a day at least for one month; former smokers were the ones who used to smoke in the past but not at the moment. Similar research was conducted in 1986 and 1991.

RESULTS/CONCLUSIONS

Smoking prevalence was 11% compared with 14% in 1991 and 21% in 1986. Although there was a significant reduction of smoking in the last three years, the actual decrease from 1991 to 1996 was less than that observed from 1986 to 1991. In 1961, the prevalence of smoking increased in the last years of medical school. There were no significant differences regarding gender. Most of the students were in favor of not allowing smoking in both the school areas and hospital wards. They also mentioned in their questionnaire that smoking was poorly approached during medical school.

Reflections on the development of CHASE Children's Hospice Service

The tasks along the way to developing a children's hospice service are examined. CHASE Children's Hospice Service aims to establish a network of care for life-limited and life-threatened children, young people and their families. The services will be provided for families living mainly in SW London, Surrey and parts of West Sussex. They will comprise a source of palliative and respite care for the children and their families in their own homes (community care), backed-up by a respite care service in the related hospice at Artington, near Guildford (Christopher's).

Lung cancer risk in nonsmokers and GSTM1 and GSTT1 genetic polymorphism

Glutathione S-transferase (GST) polymorphism may contribute to the individual variability in detoxifying lung carcinogens. This effect might be particularly relevant at low-level exposure to environmental carcinogens, such as in nonsmokers exposed to environmental tobacco smoke (ETS). We conducted a case-control study among 122 nonsmoking lung cancer cases and 121 nonsmoking controls from eight countries. Information on environmental exposures was obtained through a personal interview. The presence of GSTM1 and GSTT1 genes was determined using multiplex PCR. GSTM1-positive samples were then analyzed for *1A and *1B polymorphism using an allele-specific amplification-PCR method. GSTM1*2 (null) individuals had an odds ratio (OR) of lung cancer of 1.5 [95% confidence interval (CI), 0.9-2.7]; the risk associated with this genotype was higher for cases with squamous and small cell carcinomas (OR, 2.3; 95% CI, 0.9-6.1) than for cases with adenocarcinomas. It was also elevated in individuals with long-term exposure to indoor wood combustion (OR, 3.1; 95% CI, 0.9-9.9), in subjects who mainly lived in a rural setting (OR, 3.6; 95% CI, 1.0-13), and in cases exposed to occupational carcinogens (OR, 10.7; 96% CI, 0.4-260) but not in subjects exposed to ETS. GSTT1*2 subjects did not show a risk of lung cancer. Our study suggests that the effect of GSTM1 polymorphism in nonsmokers is similar to that found in smokers. It does not seem to interact with ETS exposure, although we cannot exclude that it does in association with exposure to other specific environmental carcinogens.

Thromboembolic disease prophylaxis in total knee arthroplasty using intraoperative heparin and postoperative pneumatic foot compression

A prospective study was performed to assess the clinical efficacy of intraoperative heparin combined with postoperative pneumatic foot compression and aspirin for thromboembolic disease prophylaxis after primary total knee arthroplasty (TKA). This group of 48 patients all had a primary TKA performed under epidural anesthesia. The cohort of patients was compared with a similar cohort of patients matched for age and comorbidity. The control group consisted of 61 patients (41 unilateral patients, 20 bilateral patients) with 81 TKAs who received epidural anesthesia and postoperative pneumatic foot compression and aspirin. The same surgeon and anesthesiologist performed all cases. All patients had the pneumatic foot compression device applied in the recovery room and received 325 mg of enteric-coated aspirin twice a day beginning the night of surgery. Venography was performed on the fifth postoperative day for both groups to determine the incidence of deep vein thrombosis (DVT). In the control group with postoperative pneumatic foot compression (group 1), the overall incidence of DVT was 27% (22 of 81), with 10% (8 of 81) major calf DVT and no proximal (popliteal or femoral) DVT. In the study group with intraoperative heparin and postoperative pneumatic foot compression (group 2), the overall incidence of DVT was 25% (12 of 48), with 8% (4 of 48) major calf DVT and no proximal DVT. There was no statistically significant difference between groups 1 and 2 for the incidence of overall DVT (P > .05) or major calf DVT (P > .05). No complications were associated with the use of intraoperative heparin or the pneumatic compression device, and no patient developed a symptomatic pulmonary embolism up to 3 months postoperatively. Although this study confirms that pneumatic foot compression combined with aspirin is an effective form of DVT prophylaxis after TKA, the added benefit of intraoperative heparin was not statistically proven. Although greater statistical power is needed to determine whether intraoperative heparin provides an added benefit, this study reveals a low incidence of DVT in TKA with this protocol.

Differing temporal roles of Ca2+ and cAMP in nicotine-elicited elevation of tyrosine hydroxylase mRNA

The involvement of cAMP- and Ca2+-mediated pathways in the activation of tyrosine hydroxylase (TH) gene expression by nicotine was examined in PC-12 cells. Extracellular Ca2+ and elevations in intracellular Ca2+ concentration ([Ca2+]i) were required for nicotine to increase TH mRNA. The nicotine-elicited rapid rise in [Ca2+]i was inhibited by blockers of either L-type or N-type, and to a lesser extent P/Q-, but not T-type, voltage-gated Ca2+ channels. With continual nicotine treatment, [Ca2+]i returned to basal levels within 3-4 min. After a lag of approximately 5-10 min, there was a smaller elevation in [Ca2+]i that persisted for 6 h and displayed different responsiveness to Ca2+ channel blockers. This second phase of elevated [Ca2+]i was blocked by an inhibitor of store-operated Ca2+ channels, consistent with the observed generation of inositol trisphosphate. 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-AM (BAPTA-AM), when added before or 2 h after nicotine, prevented elevation of TH mRNA. Nicotine treatment significantly raised cAMP levels. Addition of the adenylyl cyclase inhibitor 2', 5'-dideoxyadenosine (DDA) prevented the nicotine-elicited phosphorylation of cAMP response element binding protein. DDA also blocked the elevation of TH mRNA only when added after the initial transient rise in [Ca2+]i and not after 1 h. This study reveals that several temporal phases are involved in the induction of TH gene expression by nicotine, each of them with differing requirements for Ca2+ and cAMP.

Bacterial endophthalmitis following extracapsular cataract extraction: recommendations for early detection

OBJECTIVE

To determine the time between the onset of symptoms of endophthalmitis after cataract extraction and presentation to an ophthalmologist and to determine the spectrum of organisms responsible for postoperative endophthalmitis.

DESIGN

Case series.

SETTING

Tertiary care vitreoretinal service in Toronto.

PATIENTS

Thirty-three patients with early (presentation within 2 weeks of surgery) endophthalmitis following extracapsular cataract extraction and intraocular lens implantation performed between January 1989 and December 1992.

OUTCOME MEASURES

Time to presentation to an ophthalmologist, duration of symptoms, culture results.

RESULTS

Twenty-two patients (66.7%) were documented to experience identifiable symptoms of endophthalmitis before presentation to their ophthalmologist; the mean time of onset of symptoms was 3.6 (standard deviation [SD] 1.7) days after surgery. Of the 22 patients 16 (72.7%) became symptomatic by the fourth postoperative day, and 21 (95.4%) experienced symptoms by the fifth postoperative day. The mean delay between onset of symptoms and presentation was 1.9 (SD 1.6) days. Bacteria were identified in 27 cases (81.8%), confirmed by culture in 23 cases (69.7%). The organisms were gram-positive in 25 (92.6%) of the 27 cases, and coagulase-negative Staphylococcus predominated.

CONCLUSIONS

In our series a considerable delay existed between the development of symptoms of endophthalmitis following extracapsular cataract extraction and clinical diagnosis. This delay could be minimized by scheduling routine postoperative visits at 1 and 4 days following cataract surgery.

Involvement of intracellular or extracellular calcium in activation of tyrosine hydroxylase gene expression in PC12 cells

The relationship between elevations in intracellular free Ca2+ concentration ([Ca2+]i) by different mechanisms and tyrosine hydroxylase (TH) gene expression was examined. Depolarization by an elevated K+ concentration triggered rapid and sustained increases in [Ca2+]i from a basal level of approximately 50 to 110-150 nM and three- to fourfold elevations in TH mRNA levels, requiring extracellular calcium but not inositol 1,4,5-trisphosphate (IP3). On the other hand, bradykinin or thapsigargin, both of which induce release of intracellular calcium stores via IP3 or inhibition of Ca(2+)-ATPase, rapidly elevated [Ca2+]i to > 200 nM and increased TH gene expression (three-to fivefold). Confocal imaging showed that the elevations in [Ca2+]i in each case occurred throughout the cyto-and nucleoplasm. The initial rise in [Ca2+]i due to either bradykinin or thapsigargin, which did not require extracellular calcium, was sufficient to initiate the events leading to increased TH expression. Consistent with this, the effects of bradykinin on TH expression were inhibited by 1, 2-bis(2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid or 3,4,5-trimethoxybenzoic acid 8-(diethylamino)-octyl ester which chelates or inhibits the release of intracellular calcium, respectively. Bradykinin required a rise in [Ca2+]i for < 10 min, as opposed to 10-30 min for depolarization to increase TH mRNA levels. These results demonstrate that although each of these treatments increased TH gene expression by raising [Ca2+]i, there are important differences among them in terms of the magnitude of elevated [Ca2+]i, requirements for extracellular calcium or release of intracellular calcium stores, and duration of elevated [Ca2+]i, indicating the involvement of different calcium signalling pathways leading to regulation of TH gene expression.

Promoter elements and second messenger pathways involved in transcriptional activation of tyrosine hydroxylase by ionomycin

Membrane depolarization, or agents which increase intracellular calcium, elicit transcriptional activation of tyrosine hydroxylase (TH). In this study we analyze the factors involved in the regulation of the TH promoter by a calcium ionophore. PC12 cells were transiently transfected with plasmids containing wild type or mutated 5' flanking sequences of the rat TH gene, fused to bacterial chloramphenicol acetyl transferase (CAT). Point mutations introduced into the consensus cAMP-regulatory element (CRE) abolished the induction of CAT by ionomycin indicating that it is essential for mediating the calcium response. An intact and functional AP1 site did not confer calcium inducibility when the CRE/CaRE sequence was mutated. The extent and kinetics of the increase in intracellular calcium as well as the induction of CAT activity under the control of TH promoter by ionomycin were similar in PC12 cells and in the A123.7, protein kinase A (PKA) deficient cell line. In both cell lines addition of ionomycin rapidly increased the phosphorylation of transcription factor CREB at Ser-133. These results suggest that the activation of TH transcription by ionomycin does not require PKA. However, KN62 an inhibitor of Ca2+/calmodulin dependent (CaM) kinases prevented the induction indicating possible involvement of CAM kinases in the calcium response.

Congenital fourth nerve palsy and occult cranium bifidum

A 6-year-old girl had paresis of the fourth cranial nerve since infancy. Computed tomography and magnetic resonance imaging revealed occult cranium bifidum with elevation of the straight sinus and tentorium, an abnormal tectal configuration, and a mass in the posterior fossa. Surgical resection revealed that the mass consisted of adipose and fibrous connective tissue. This patient further illustrates that congenital fourth cranial nerve palsy is associated in rare instances with anomalies of the brainstem and adjacent structures.

Cerebral hemiatrophy, hypoplasia of internal carotid artery, and intracranial aneurysm. A rare association occurring in an infant

A 4-month-old child with a very rare association of primary (congenital) left cerebral hypoplasia, hypoplasia of the left internal carotid artery, and giant anterior communicating artery aneurysm was seen. The aneurysm was detected and treated before rupture. We briefly reviewed the literature on agenesis (hypoplasia) of the internal carotid artery, intracranial aneurysms in childhood, and primary cerebral hypoplasia. It is proposed that cerebral arteriography, cranial computed tomography, or magnetic resonance imaging be performed in all children with primary cerebral hemihypoplasia to establish an etiologic diagnosis and, more importantly, to detect and treat possible associated intracranial aneurysms before they become symptomatic.

Magnetic resonance imaging of the spine in children

We reviewed the magnetic resonance imaging (MRI) scans of the spine of 42 children who had neurologic signs compatible with lesions of the spinal cord. Twenty-three of the children had abnormalities identified by MRI. The spectrum of abnormalities included posttraumatic lesions, tumor, tethered cord, and syringohydromyelia. Tethered cord with or without lipoma and syringohydromyelia were the most common findings, affecting six and four children, respectively. Thirteen children studied by MRI also underwent conventional metrizamide myelography and/or computed tomography. In 12 cases, the findings of MRI were comparable to those of myelography and computed tomography. These observations indicate that MRI effectively detects lesions of the spinal cord in children. Because MRI can be performed on an outpatient basis and avoids the risks of metrizamide myelography, we conclude that MRI should be considered to be the preferred screening technique for children with suspected spinal cord disorders.

Medulloblastoma with glial and rhabdomyoblastic differentiation. A myoglobin and glial fibrillary acidic protein immunohistochemical and ultrastructural study

This is a report of an unusual, densely cellular, midcerebellar neoplasm in a seven-year-old boy. Although clinically consistent with a medulloblastoma, immunohistochemistry and electron microscopy demonstrated glial and rhabdomyoblastic differentiation in the tumor. We discuss the differential diagnosis of this tumor as it relates to glial differentiation in medulloblastomas and the myogenic potential of primitive neuroectoderm.

Management of Reye's syndrome. A rational approach to a complex problem

Five patients suffering from progressive Reye's syndrome were aggressively treated in our ICU. Our protocol consisted of endotracheal intubation, curarization, mechanical ventilation, hypothermia to 31 degrees C, and fluid restriction. Intracranial pressure (ICP) was monitored and remained below 10-20 torr in all patients except one in whom ICP rose only once (for a few minutes) to 27 torr. Pulmonary artery wedge pressure was monitored in 4 patients and was maintained at 4-5 torr. Duration of active intervention as outlined above was 3-4 days. All 5 patients started with clinical stage IV and EEG grade IV or worse. Four patients had complete recovery and one died. In this group of patients, high ICP was not a feature of the disease. We recommend that use of mannitol for active dehydration be reserved for cases with proven rise in ICP, in which case hemodynamics should be carefully monitored.