Diagnostic findings in sinonasal aspergillosis in dogs in the United Kingdom: 475 cases (2011-2021)

OBJECTIVES

To describe the diagnostic tests used and their comparative performance in dogs diagnosed with sinonasal aspergillosis in the United Kingdom. A secondary objective was to describe the signalment, clinical findings and common clinicopathologic abnormalities in sinonasal aspergillosis.

MATERIALS AND METHODS

A multi-centre retrospective survey was performed involving 23 referral centres in the United Kingdom to identify dogs diagnosed with sinonasal aspergillosis from January 2011 to December 2021. Dogs were included if fungal plaques were seen during rhinoscopy or if ancillary testing (via histopathology, culture, cytology, serology or PCR) was positive and other differential diagnoses were excluded.

RESULTS

A total of 662 cases were entered into the database across the 23 referral centres. Four hundred and seventy-five cases met the study inclusion criteria. Of these, 419 dogs had fungal plaques and compatible clinical signs. Fungal plaques were not seen in 56 dogs with turbinate destruction that had compatible clinical signs and a positive ancillary test result. Ancillary diagnostics were performed in 312 of 419 (74%) dogs with observed fungal plaques permitting calculation of sensitivity of cytology as 67%, fungal culture 59%, histopathology 47% and PCR 71%.

CLINICAL SIGNIFICANCE

The sensitivities of ancillary diagnostics in this study were lower than previously reported challenging the clinical utility of such tests in sinonasal aspergillosis. Treatment and management decisions should be based on a combination of diagnostics including imaging findings, visual inspection, and ancillary testing, rather than ancillary tests alone.

The other great imitator among infectious diseases: Leptospirosis

INTRODUCTION

Leptospirosis is a worldwide zoonosis responsible for highly diverse clinical presentations with a wide range of severity. Variable environment exposures to infected urines of rodents have been described.

OBSERVATION

We report five cases of serologically confirmed leptospirosis leading to hospitalization in an intensive care unit (ICU) of a French center. These patients displayed neurological, respiratory, and abdominal presentation of leptospirosis with variable level of severity. Either professional, leisure related, or daily living exposures have been retrieved.

CONCLUSION

These cases underline the diversity of clinical presentation and environmental exposure of this infectious disease. They highlight the interest of an exhaustive anamnesis with collection of professional activity, environmental exposures, and leisure activities.

Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

Fermentation of liquid feed with lactic acid bacteria reduces dry matter losses, lysine breakdown, formation of biogenic amines and phytate-phosphorus

This study investigated the fermentation of liquid feed for pigs and the effect of lactic acid bacteria (LAB) supplementation on fermentation rate, dry matter losses (DML), formation of biogenic amines, and degradation of phytate-P. The basal substrate in all three in vitro batch experiments consisted of 50% canola meal, 25% wheat, and 25% barley. The mixed substrates were adjusted to a dry matter (DM) content of 28.4% and fermented in 1-liter vessels at 37 °C for 24 h. Experiment 1 focused on changes in pH profiles over time. Treatments were as follows: 1) liquid feed without additive (control) and 2) liquid feed supplemented with a mixture of Lactobacillus plantarum, Pediococcus pentosaceus, and Lactobacillus lactis (adLAB) at 2.0 × 10⁵ CFU/g liquid feed (wet wt.; n = 8). Substrate pH was measured every 2 h. Experiment 2 focused on DML and the impact of fermentation on phytate-P. Treatments were identical to experiment 1 (control and adLAB; n = 8). Measured parameters included concentration of lactic acid, acetic acid, ethanol, and phytate-P, and DML after 24 h of fermentation. Counts of molds, Enterobobacteriaceae, yeasts, and LAB were determined in one combined sample of all replicates. Dry matter losses were lower in LAB-supplemented fermentations (5.89%) compared to the control (11.8%; P < 0.001). Supplementation with LAB reduced the phytate-P content (2.66 g/kg DM) compared to the control (3.07 g/kg DM; P = 0.002). Experiment 3 evaluated DML and the impact of fermentation on formation of biogenic amines. Treatments were as follows: 1) control, 2) adLAB (2.0 × 10⁵ CFU LAB/g liquid feed), 3) adLys (0.60% DM supplemented lysine), and 4) adLAB+Lys (combination of adLAB and adLys; n = 8). The fermentation of adLys resulted in a nearly complete breakdown of supplemented lysine, whereas only 10% of supplemented lysine was lost in adLAB+Lys. Furthermore, all adLys samples tested positive for cadaverine (mean concentration 0.89% DM), whereas no adLAB samples contained cadaverine above the detection limit (P < 0.001). Results indicate that DML is reduced in fermentations supplemented with homofermentative LAB. Fermentation of liquid feed with homofermentative LAB can effectively reduce the degradation of supplemental lysine and has the potential to further improve P availability.

Invasive aspergillosis and endocarditis

INTRODUCTION

Aspergillusfumigatus can cause a systemic infection called invasive aspergillosis causing pulmonary and extra-pulmonary damage. Aspergillus endocarditis (AE) is a relatively rare disease but can be life-threatening.

CASE REPORTS

We report here on five cases of endocarditis due to invasive aspergillosis: a 58-year-old man receiving immunosuppressive medication following a kidney graft, a 58-year-old man undergoing chemotherapy for chronic lymphocytic leukaemia, a 55-year-old man receiving corticosteroids for IgA vasculitis, a 52-year-old HIV-infected woman under no specific treatment and a 17-year-old boy under immunosuppressive therapy for auto-immune chronic neutropenia.

DISCUSSION

Aspergillus accounts for 25-30% of fungal endocarditis and 0.25% to 8.5% of all cases of infectious endocarditis. Aspergillus endocarditis results from invasion of the lung arterioles by hyphae and blood dissemination. It is associated with a very high mortality rate (42-68%). Diagnosing Aspergillus endocarditis is mainly problematic because blood cultures are almost always negative, and fever may be absent. Immunosuppression, haematological malignancies, recent cardiothoracic surgery, negative blood cultures with endocarditis and/or systemic or pulmonary emboli are predictors of AE. In the setting of endocarditis, some clinical characteristics may raise early suspicions of aspergillosis rather than a non-fungal agent: no fever, vegetations affecting the mitral valve, non-valve or aortotomy sites, aortic abscess or pseudo-aneurysm. The identification of invasive aspergillosis is based on a chest CT scan, microscopy/culture or other serological and molecular tests. The treatment of Aspergillus endocarditis requires triazole antifungal drugs, and frequently additional surgical debridement.

CONCLUSION

Aspergillus endocarditis is rare but is associated with a very high mortality rate. Knowledge of its predictive factors and key clinical features can help to differentiate aspergillosis from non-fungal endocarditis and may enable improved survival rates.

137 ancient human genomes from across the Eurasian steppes

For thousands of years the Eurasian steppes have been a centre of human migrations and cultural change. Here we sequence the genomes of 137 ancient humans (about 1× average coverage), covering a period of 4,000 years, to understand the population history of the Eurasian steppes after the Bronze Age migrations. We find that the genetics of the Scythian groups that dominated the Eurasian steppes throughout the Iron Age were highly structured, with diverse origins comprising Late Bronze Age herders, European farmers and southern Siberian hunter-gatherers. Later, Scythians admixed with the eastern steppe nomads who formed the Xiongnu confederations, and moved westward in about the second or third century BC, forming the Hun traditions in the fourth-fifth century AD, and carrying with them plague that was basal to the Justinian plague. These nomads were further admixed with East Asian groups during several short-term khanates in the Medieval period. These historical events transformed the Eurasian steppes from being inhabited by Indo-European speakers of largely West Eurasian ancestry to the mostly Turkic-speaking groups of the present day, who are primarily of East Asian ancestry.

Ancient hepatitis B viruses from the Bronze Age to the Medieval period

Hepatitis B virus (HBV) is a major cause of human hepatitis. There is considerable uncertainty about the timescale of its evolution and its association with humans. Here we present 12 full or partial ancient HBV genomes that are between approximately 0.8 and 4.5 thousand years old. The ancient sequences group either within or in a sister relationship with extant human or other ape HBV clades. Generally, the genome properties follow those of modern HBV. The root of the HBV tree is projected to between 8.6 and 20.9 thousand years ago, and we estimate a substitution rate of 8.04 × 10^-6-1.51 × 10^-5 nucleotide substitutions per site per year. In several cases, the geographical locations of the ancient genotypes do not match present-day distributions. Genotypes that today are typical of Africa and Asia, and a subgenotype from India, are shown to have an early Eurasian presence. The geographical and temporal patterns that we observe in ancient and modern HBV genotypes are compatible with well-documented human migrations during the Bronze and Iron Ages^1,2. We provide evidence for the creation of HBV genotype A via recombination, and for a long-term association of modern HBV genotypes with humans, including the discovery of a human genotype that is now extinct. These data expose a complexity of HBV evolution that is not evident when considering modern sequences alone.

Optimal Reuse of Cuprammonium Rayon Hollow-Fibre Dialyzers

The optimal number of times a hollow-fibre cuprammonium rayon (Terumo TAF) dialyzer could be used was determined in twelve patients. Each dialyzer was reused six times. There was a highly significant decrease in neutrophil count (46.9± 6.9%, mean ± s.e.m.), platelet count (9.6± 3.8%, mean ± s.e.m.) and serum C3 concentration (10.25± 2.4%, mean ± s.e.m.) 30 minutes after the commencement of dialysis. The intensity of these changes decreased with the reuse of the dialyzers up to the fourth time. There was a small, but significant increase in serum β2-microglobulin concentrations after a 6-hour dialysis. The difference between pre- and post-dialysis serum β2-microglobulin concentrations appeared to be greater during the 5th and the 6th use (18.8% and 20.5% vs 5.0% during the first use). The clearance rates of urea and creatinine showed a trend to decrease from the fourth use onwards and the ultrafiltration coefficient was significantly reduced from the third use (8.5± 4.0 mean ± s.e.m.) onwards so that at the sixth use it was only 75.8± 4.8%, (mean ± s.e.m.) of the value at the first use. It is concluded that the optimal number of uses a cuprammonium rayon hollow-fibre dialyzer can be put to is four.

Concurrent colorectal malignancy and abdominal aortic aneurysm: a multicentre experience and review of the literature

OBJECTIVES

There is lack of consensus regarding concurrent vs. staged approaches, and the prioritisation of staged procedures in cases presenting with colorectal carcinoma (CRC) and abdominal aortic aneurysm (AAA) synchronously. We aim to present our experience, review the literature on this therapeutic dilemma and examine the role of endovascular aortic repair (EVAR).

DESIGN, MATERIALS AND METHODS

An observational study of the experience of two centres and a systematic review of the published literature.

RESULTS

Twenty-four patients were identified from the prospective databases of two tertiary referral centres between 2001 and 2006. Intervention for both malignancy and aneurysm was performed in 13 patients. In 10 patients, cancer resection was performed initially and was followed by open aneurysm repair (n=3) or EVAR (n=7). Two patients (AAA diameters: 7.0 and 8.0cm) underwent EVAR prior to colonic resection. One patient was selected for synchronous surgery. There were no interval AAA ruptures, graft infection or postoperative mortalities. Literature review identified 269 such cases; of these 101 were treated by combined surgery. In staged surgery, there were nine interval aneurysmal ruptures and one aortic graft infection.

CONCLUSIONS

In our experience, staged management can be undertaken, without interval aneurysmal rupture. EVAR has an evolving role in preventing delay in CRC management, in high-risk patients, and during combined intervention.

Photoacoustic imaging endoscope

We currently present a design concept for a photoacoustic imaging endoscope as well as some preliminary experimental results. The device is based on the generation of acoustic waves in tissue by short laser pulses and the sensing of these waves with a thin, optical Fabry-Pérot etalon. The entire device is designed to be mounted on the tip of a needle to deliver high-resolution photoacoustic imaging for minimally-invasive clinical applications such as diagnosing kidney disease and guiding laparoscopic surgery.

Isotype-specific Ras.GTP-levels predict the efficacy of farnesyl transferase inhibitors against human astrocytomas regardless of Ras mutational status

Previous studies have demonstrated that astrocytomas express elevated levels of activated Ras.GTP despite the absence of activating Ras mutations. Farnesyl transferase inhibitors (FTIs) exert their antitumor effect in part through inhibition of Ras-mediated signaling. SCH66336 is a potent FTI presently undergoing clinical trials in patients with solid tumors. We evaluated the efficacy of SCH66336 against a panel of eight human astrocytoma cell lines and three human astrocytoma explant xenograft models in NOD-SCID mice. SCH66336 demonstrated variable antiproliferative effects against the cell lines, with IC(50) ranging from 0.6 microM to 32.3 microM. Two of the three human glioblastoma multiforme (GBM) xenografts demonstrated substantial growth inhibition in response to SCH66336, with up to 69% growth inhibition after 21 days of treatment. Drug efficacy could be accurately predicted using a combination of the H-, K-, and N-isotype-specific Ras.GTP levels. These data indicate that the absence of Ras mutations does not preclude chemotherapeutic efficacy by FTIs, that Ras is likely a major target of FTIs regardless of Ras mutational status, and that isotype-specific Ras.GTP levels are a promising marker of drug efficacy.

Expression and hypoxic regulation of angiopoietins in human astrocytomas

Vascular endothelial growth factor (VEGF) is a major inducer of tumor angiogenesis and edema in human astrocytomas by its interaction with cognate endothelial-specific receptors (VEGFR1/R2). Tie1 and Tie2/Tek are more recently identified endothelial-specific receptors, with angiopoietins being ligands for the latter. These angiogenic factors and receptors are crucial for the maturation of the vascular system, but their role in tumor angiogenesis, particularly in astrocytomas, is unknown. In this study, we demonstrate that the angiopoietin family member Ang1 is expressed by some of the astrocytoma cell lines. In contrast to VEGF, Ang1 is down regulated by hypoxia. Ang2 was not overexpressed. Expression profiles of low-grade astrocytoma specimens were similar to those of normal brain, with low levels of Ang1, Ang2, and VEGF expression. Glioblastoma multiforme expressed higher levels of Angl, but not to the same degree as pseudopalisading astrocytoma cells around necrotic and hypoxic zones expressed VEGF, as shown in previous studies. Ang2 expression in the highly proliferative tumor vascular endothelium was also increased, as was phosphorylated Tie2/Tek. The expression profile of these angiogenic factors and their endothelial cell receptors in human glioblastomas multiforme was similar to that in a transgenic mouse model of glioblastoma multiforme. These data suggest that both VEGF and angiopoietins are involved in regulating tumor angiogenesis in human astrocytomas.

Astrocyte-specific expression of activated p21-ras results in malignant astrocytoma formation in a transgenic mouse model of human gliomas

Activation of the p21-ras signaling pathway from aberrantly expressed receptors promotes the growth of malignant human astrocytomas. We developed a transgenic mouse astrocytoma model using the glial fibrillary acidic protein (GFAP) promoter to express oncogenic V(12)Ha-ras, specifically in astrocytes. The development of GFAP-immunoreactive astrocytomas was directly proportional to the level of V(12)Ha-ras transgene expression. Chimeras expressing high levels of V(12)Ha-ras in astrocytes died from multifocal malignant astrocytomas within 2 weeks, whereas those with moderate levels went to germ-line transmission. Ninety-five percent of these mice died from solitary or multifocal low- and high-grade astrocytomas within 2-6 months. These transgenic astrocytomas are pathologically similar to human astrocytomas, with a high mitotic index, nuclear pleomorphism, infiltration, necrosis, and increased vascularity. Derivative astrocytoma cells are tumorigenic upon inoculation in another host. The transgenic astrocytomas exhibit additional molecular alterations associated with human astrocytomas, including a decreased or absent expression of p16, p19, and PTEN as well as overexpression of EGFR, MDM2, and CDK4. Cytogenetic analysis revealed consistent clonal aneuploidies of chromosomal regions syntenic with comparable loci altered in human astrocytomas. Therefore, this transgenic mouse astrocytoma model recapitulates many of the molecular histopathological and growth characteristics of human malignant astrocytomas in a reproducible, germ-line-transmitted, and high-penetrance manner.

Expression and hypoxic regulation of angiopoietins in human astrocytomas

Vascular endothelial growth factor (VEGF) is a major inducer of tumor angiogenesis and edema in human astrocytomas by its interaction with cognate endothelial-specific receptors (VEGFR1/R2). Tie1 and Tie2/Tek are more recently identified endothelial-specific receptors, with angiopoietins being ligands for the latter. These angiogenic factors and receptors are crucial for the maturation of the vascular system, but their role in tumor angiogenesis, particularly in astrocytomas, is unknown. In this study, we demonstrate that the angiopoietin family member Ang1 is expressed by some of the astrocytoma cell lines. In contrast to VEGF, Ang1 is down regulated by hypoxia. Ang2 was not overexpressed. Expression profiles of low-grade astrocytoma specimens were similar to those of normal brain, with low levels of Ang1, Ang2, and VEGF expression. Glioblastoma multiforme expressed higher levels of Angl, but not to the same degree as pseudopalisading astrocytoma cells around necrotic and hypoxic zones expressed VEGF, as shown in previous studies. Ang2 expression in the highly proliferative tumor vascular endothelium was also increased, as was phosphorylated Tie2/Tek. The expression profile of these angiogenic factors and their endothelial cell receptors in human glioblastomas multiforme was similar to that in a transgenic mouse model of glioblastoma multiforme. These data suggest that both VEGF and angiopoietins are involved in regulating tumor angiogenesis in human astrocytomas.

Expression and regulation of neuropilin-1 in human astrocytomas

Vascular endothelial growth factor (VEGF), through activation of its endothelial receptors VEGFR-1 and VEGFR-2, is an important positive modulator of tumor angiogenesis and edema in solid tumors such as malignant astrocytomas. Neuropilin-1 (Npn-1) is a transmembrane receptor expressed by both endothelial and non-endothelial cells, including tumor cells. Npn-1 has been postulated to function as a co-factor in activation of the biologically relevant VEGFR-2, by the most abundant VEGF165 isoform. However, the function of Npn-1 in normal and pathological angiogenesis, its expression pattern in relation to VEGF in tumors such as astrocytomas and whether it is similarly or differentially regulated compared to VEGF remain unknown. In our study, the expression pattern of Npn-1 and VEGF by human astrocytoma cell lines and specimens was closely correlated and associated with malignant astrocytomas. Mitogens, such as epidermal growth factor and activation of p21-Ras, previously demonstrated to be relevant in astrocytoma proliferation and induction of VEGF, also induce Npn-1 expression. Hypoxia, the main physiological inducer of VEGF expression, decreased Npn-1 expression. Increased Npn-1 expression was also demonstrated in a transgenic mouse astrocytoma model. Astrocytomas are an ideal system for furthering our understanding of the functional relevance, if any, of Npn-1 in tumor angiogenesis.

A risk factor screening and assessment protocol for schizophrenia and related psychosis

OBJECTIVE

The Psychological Assistance Service (PAS) opened in Newcastle, New South Wales in 1997 as a clinical service for the assessment and treatment of young people at high risk of psychosis and those experiencing a first psychotic episode. The aim of this paper is to describe the assessment protocol of PAS, which is strongly influenced by the neurodevelopmental perspective on early onset psychosis.

METHOD

The systematic assessment of patients referred to PAS using a protocol over a 2 week period is described. The protocol includes a narrative history, structured diagnostic interview, quantitative assessment of symptoms and other clinical features, a neurological examination and comprehensive neuropsychological test battery.

RESULTS

The clinic has received over 250 referrals in a 2 year period and accepted 116 patients for a full assessment, of whom 60 were deemed to be 'at-risk' of psychosis and 56 were experiencing their first psychotic episode. Both groups were similar with respect to gender and there were minor age differences. The first-episode group experienced more reality distortion, schizotypal and negative symptoms. While both groups showed some neuropsychological and neurological impairment, there were no statistically significant differences between the groups on these variables except for a test of executive functioning in which the first-episode group was more impaired than the 'at-risk' group. A low rate of conversion to psychosis occurred in the 'at-risk' group.

CONCLUSIONS

The minor differences between the two groups may have been related to relatively small sample sizes, although some similarities between the groups were to be expected. The low rate of conversion to psychosis in the 'at-risk' group is discussed. Further analyses using larger samples are necessary to determine the validity of the various 'at-risk' categories and this will involve following a sufficiently large sample over an adequate time. The most efficient way of doing this would be to pool data across centres with comparable early intervention programs.

Loss of neurofibromin is associated with activation of RAS/MAPK and PI3-K/AKT signaling in a neurofibromatosis 1 astrocytoma

Neurofibromatosis 1 (NF1) is a common autosomal dominant cancer predisposition syndrome, in which 15% to 20% of affected individuals develop astrocytomas. Neurofibromin, the protein product of the NF1 gene, functions as a tumor suppressor, largely by inhibiting Ras activity. While loss of neurofibromin has been implicated in the molecular pathogenesis of other NF1-associated tumors, there is no formal evidence demonstrating loss of neurofibromin function in NF1-associated astrocytomas. In this report, we describe an NF1 patient from whom both astrocytoma tumor tissue as well as corresponding non-neoplastic white matter were available for analysis. Loss of neurofibromin expression was observed in the tumor and was associated with elevated levels of Ras-GTP. However, elevated Ras-GTP levels were not the result of oncogenic Ras mutations, altered p120-GAP function, growth factor receptor activation, or abnormal p53, Rb, or p16 expression. Furthermore, increased Raf-MAPK and PI3-K/Akt activity was detected in the NF1 astrocytoma compared with the corresponding normal white matter. These results support a role for neurofibromin as the critical GAP in the molecular pathogenesis of NF1 astrocytomas.

Growth inhibition of astrocytoma cells by farnesyl transferase inhibitors is mediated by a combination of anti-proliferative, pro-apoptotic and anti-angiogenic effects

While 25% of human cancers harbor oncogenic Ras mutations, such mutations are not found in astrocytomas. We have previously demonstrated that the activation of receptor tyrosine kinases expressed by malignant human astrocytoma cells and specimens results in functional upregulation of the Ras signalling pathway and increased levels of activated Ras*GTP. Farnesyl transferase inhibitors (FTIs) are promising anti-cancer agents in early clinical trials, which may exert their effect through pharmacological inhibition of the Ras signalling pathway. In this study we establish the anti-tumorigenic properties of the FTI L-744,832 against a panel of malignant human astrocytoma cell lines. Furthermore, we demonstrate the multiple mechanisms by which L-744,832 exerts its effect. L-744,832 demonstrates both cytostatic and cytotoxic effects on astrocytoma cells, and cells expressing a truncated constitutively phosphorylated Epidermal Growth Factor Receptor common in high-grade astrocytomas (EGFRvIII/p140EGF-R) demonstrate increased sensitivity to the agent. L-744,832 is capable of inducing apoptosis in astrocytoma cells under anchorage-dependent conditions; this process occurs in a p53-independent manner and is associated with increased expression of Bax and Bak. L-744,832 also induces cell cycle arrest at both the G1/M and G2/S checkpoints; this process is also independent of p53 mutational status. Cell cycle arrest in drug-treated cells can be accompanied by induction of p21WAF1/CIP1, but this induction is not necessary for the cell cycle inhibitory effects, nor is it dependent on functional p53. Finally, angiogenesis in astrocytomas has been shown to be dependent on secretion of Vascular Endothelial Growth Factor (VEGF) by tumour cells, particularly under hypoxic conditions. L-744,832 potently inhibits the secretion of VEGF under hypoxic conditions. These combinations of mechanisms suggest that these tumours, despite the absence of oncogenic Ras mutations, will be amenable to growth inhibition by FTIs, through a combination of anti-proliferative, pro-apoptotic, and anti-angiogenic effects.

Expression of activated epidermal growth factor receptors, Ras-guanosine triphosphate, and mitogen-activated protein kinase in human glioblastoma multiforme specimens

OBJECTIVE

Amplification of the epidermal growth factor receptor (EGFR) is a common event in the molecular pathogenesis of high-grade astrocytic tumors, occurring in 50% of glioblastoma multiforme (GBM) cases. A subset of GBMs also express a constitutively phosphorylated truncated receptor (EGFRvIII). Expression of transfected EGFRvIII in cells has been reported to activate the Ras-mitogen-activated protein kinase pathway and to provide a growth advantage. Novel therapeutic agents targeting signal transduction pathways are entering early clinical trials; determination of which GBMs express EGFRvIII might help identify patients who might benefit from these biological agents.

METHODS

A cohort of 15 flash-frozen surgical specimens (12 GBMs, 2 gliosarcomas, and 1 adult low-grade glioma) were evaluated for EGFR and EGFRvIII expression and for EGFR activation status using immunohistochemical (IHC) analysis, Western blotting, and reverse transcription-polymerase chain reaction assays. Levels of activated Ras-guanosine triphosphate were measured using a nonradioactive luciferase-based technique. Mitogen-activated protein kinase activation was determined using a myelin basic protein assay. IHC analysis was performed on paraffin-embedded, formalin-fixed, pathological specimens. Normal control samples included white matter specimens distal to tumors (n = 5), a sample obtained during a lobectomy for treatment of epilepsy (n = 1), and cultured fetal human astrocytes (n = 1).

RESULTS

We demonstrated higher levels of activated Ras and mitogen-activated protein kinase in GBM specimens, compared with normal brain tissue or the low-grade glioma. There was a very good correlation between results obtained using specialized molecular techniques and those obtained using routine IHC techniques. Screening for EGFRvIII expression may be of prognostic importance, because patients with EGFRvIII-positive tumors exhibited shorter life expectancies (mean survival time for patients with EGFRvIII-positive tumors, 4.5 +/- 0.6 mo; mean survival time for patients with EGFRvIII-negative tumors, 11.2 +/- 0.9 mo).

CONCLUSION

We demonstrated that routine IHC techniques using commercially available antibodies are capable of identifying which GBM specimens express EGFRvIII and whether the EGFRs are activated. Such a molecular classification of GBMs might allow us to determine which patients might benefit from biologically targeted therapies. In addition, characterization of specimens with respect to their EGFRvIII status seems to be of prognostic value.

Glucose intolerance and 23-year risk of coronary heart disease and total mortality: the Honolulu Heart Program

OBJECTIVE

The associations between glucose intolerance measured at the study entry date and the 23-year incidence of coronary heart disease (CHD), CHD mortality, and total mortality were examined at the Honolulu Heart Program.

RESEARCH DESIGN AND METHODS

This prospective study followed a cohort of 8,006 Japanese-American men who were 45-68 years old and living on the island of Oahu, HI, in 1965. Baseline glucose was measured in a nonfasting state 1 h after a 50-g glucose load. History and use of medication for diabetes was obtained during an interview. The cohort was divided into four categories of glucose tolerance: low-normal, high-normal, asymptomatic hyperglycemia, and known diabetes.

RESULTS

During the 23 years of follow-up, 864 incident cases of CHD, 384 deaths from CHD, and 2,166 total deaths occurred. The relative risks (RRs) were obtained using Cox proportional hazards modeling, with the low-normal category as a reference. The RRs were adjusted for age only, as well as for age, BMI, hypertension, cholesterol, triglycerides, smoking, alcohol, and a Japanese diet index. The age-adjusted and risk factor-adjusted RRs for all outcomes were significant for the asymptomatic hyperglycemic and known diabetes groups (P<0.05). The age-adjusted RRs for CHD incidence and total mortality were marginally significant in the high-normal group, but the RRs were not significant when adjusted for risk factors.

CONCLUSIONS

These results suggest a dose-response relation of glucose intolerance at baseline with CHD incidence, CHD mortality, and total mortality, independent of other risk factors, in this cohort of middle-aged and older Japanese-American men.

Normoxic and hypoxic regulation of vascular endothelial growth factor (VEGF) by astrocytoma cells is mediated by Ras

Vascular endothelial growth Factor (VEGF) has been identified as a key angiogenic factor involved in the growth and malignant progression of tumours. Glioblastoma multiforme (GBM) are the most common primary human brain tumours, histo-pathologically characterized by intense tumour angiogenesis. GBMs do not harbour oncogenic Ras mutations, but there is a functional up-regulation of Ras signaling through activation of receptor tyrosine kinases overexpressed by these tumours. We demonstrate that Ras pathway activation regulates VEGF secretion in astrocytoma cell lines. Ras pathway inhibition was carried out using genetic and pharmacologic techniques. Astrocytoma cells that were transfected to express the dominant inhibitory mutant H-Ras(N17) demonstrated a reduction in VEGF secretion under both normoxic and hypoxic conditions. Cells treated with the farnesyl transferase inhibitor L-744,832 demonstrated similar reductions in VEGF secretion. Furthermore, astrocytoma cells expressing a constitutively phosphorylated and truncated EGF-R common in GBMs (EGFRvIII or p140(EGF-R)) demonstrate further elevations in Ras activation, resulting in a further increase in VEGF secretion. We have previously demonstrated that activation of Ras plays a vital role in transducing mitogenic signals in human malignant astrocytoma cells. Our present results further extend the role of Ras activation in modulating tumour angiogenesis in these tumours. We propose that Ras may contribute to the angiogenic switch in astrocytomas.

Prevalence of Toxocara canis in dogs in the City of Havana

A study on the prevalence of Toxocara canis in domestic dogs of City of Havana was carried out for the first time in Cuba. 22 dogs were selected in each municipality, totalling 330 as the study universe. Dogs' feces samples were processed through direct examination using Willis' flotation method (1921). The results attained showed a 17.9% prevalence of Toxocara canis, a high figure constituting an important risk factor for transmission to humans. This was influenced by the age of the animals and the hygienic conditions of the houses, significant factors from the epidemiological point of view. Sex did not play a significant role.

Proliferation of human malignant astrocytomas is dependent on Ras activation

Overexpression and activation of receptor tyrosine kinases, such as platelet derived growth factor receptors (PDGFRs) and epidermal growth factor receptor (EGFR), leads to proliferation of human malignant astrocytoma cells. Although oncogenic mutations affecting Ras are not prevalent in human malignant astrocytomas, we have investigated whether levels of activated Ras.GTP might be elevated in these tumors secondary to the mitogenic signals originating from activated receptor tyrosine kinases. In support of this hypothesis high levels of Ras.GTP, similar to those found in oncogenic Ras transformed fibroblasts, were present in four established human malignant astrocytoma cell lines which express PDGFRs and EGFR, and 20 operative malignant astrocytoma specimens. Stimulation of PDGFR's and EGFR's induced tyrosine phosphorylation of the Shc adaptor protein and its association with Grb2, suggesting a mechanism by which Ras may be activated in human malignant astrocytoma cells. Furthermore, blocking Ras activation by expression of the Ha-Ras-Asn17 dominant-negative mutant, or by farnesyl transferase inhibitors, decreased in vitro proliferation of the human astrocytoma cell lines. These results support the hypothesis that proliferative signals from receptor tyrosine kinases expressed by human malignant astrocytoma cells utilize the Ras mitogenic pathway. Pharmacological inhibitors of the Ras pathway may therefore be of therapeutic value in these presently terminal tumors.

Signal transduction pathways and their relevance in human astrocytomas

Aberrations in a number of signal transduction pathways have been identified as playing a key role in the molecular pathogenesis of astrocytomas and their progression to high grade glioblastoma multiforme (GBM). GBMs are characterized by overexpression of the Platelet Derived Growth Factor Receptors (PDGFR) and their ligands (PDGF), as well as the Epidermal Growth Factor Receptor (EGF-R). These receptors activate the Ras pathway, a key cellular signal transduction pathway, culminating in the activation of a wide range of Ras-dependent cellular events. GBMs have also been found to either overexpression or lose expression of various Protein Kinase C (PKC) isoforms. Major strides are being made in developing pharmacological agents which specifically inhibit these growth factor receptors and intracellular signal transduction pathways. Elucidating the role of these pathways in GBMs is thus of major clinical importance, as these novel molecularly-targeted agents may prove of use in the clinical management of GBMs in the future.

Expression and activation of epidermal growth factor receptors in meningiomas

Previous studies have demonstrated expression of epidermal growth factor receptors (EGFRs) in human cerebral meningiomas. However, the activation status of the EGFRs and whether they activate cytoplasmic mitogenic signaling pathways are not known. In this study, using Northern blot analysis and the polymerase chain reaction, the authors report expression of epidermal growth factor, transforming growth factor-alpha, and EGFR messenger RNA in 27 meningioma specimens. Using Western blot and immunohistochemical analyses of the meningioma samples, the authors demonstrate that the EGFRs expressed by these meningiomas are activated. These activated EGFRs interact with and phosphorylate Shc, an SH2 domain-containing adapter protein that is important in transducing mitogenic signals from EGFRs to the nucleus via activation of the Ras signaling pathway. These results support the concept that activation of EGFRs in human meningiomas by autocrine/paracrine stimulation may contribute to their proliferation.

Meningiomas: role of vascular endothelial growth factor/vascular permeability factor in angiogenesis and peritumoral edema

OBJECTIVE

Vascular endothelial growth factor (VEGF)/vascular permeability factor (VPF) is a potent angiogenic growth factor implicated in the tumor angiogenesis/metastasis of a number of human cancers. Activation of receptors for VEGF/VPF is specifically mitogenic to endothelial cells and increases their permeability. Although extensive literature exists regarding VEGF/VPF in human astrocytomas, little is known about its potential biological role(s) in meningiomas. Our interest in meningiomas was initiated by the observation that some meningiomas are extremely vascular and are occasionally associated with a considerable degree of peritumoral brain edema, both potentially related to the biological attributes of VEGF/VPF.

METHODS

As a first test of this hypothesis, we examined a cohort of 18 meningiomas for expression of VEGF/VPF at the messenger ribonucleic acid and protein levels and correlated expression with pathological characteristics, vascularity, and degree of peritumoral edema.

RESULTS

The majority of meningiomas expressed VEGF/VPF at both the messenger ribonucleic acid and protein levels. Corresponding serial sections were stained with an endothelial cell marker to obtain a microvascular density count, which positively correlated (P = 0.0005) with expression of VEGF/VPF. Furthermore, meningiomas with a large amount of peritumoral edema, as determined from the preoperative computed tomographic scans or magnetic resonance imaging scans, had elevated expression of VEGF/VPF (P = 0.05).

CONCLUSION

These data suggest that VEGF/VPF may play a role in both meningioma vascularity and peritumoral edema.

Increased neurofibromatosis 1 gene expression in astrocytic tumors: positive regulation by p21-ras

The neurofibromatosis 1 (NF1) gene has been implicated in astrocyte growth regulation in several studies. To determine whether loss of NF1 expression is associated with progression towards malignancy in sporadic astrocytomas from individuals without NF1, twenty-eight fresh astrocytoma operative specimens (low and high grade tumors) and seven primary human astrocytoma cell lines were examined for NF1 mRNA and protein expression. In all astrocytomas examined, increased NF1 expression was observed in the tumors relative to normal resting astrocytes. This increased neurofibromin expression correlated with elevated levels of activated p21-ras measured in both the fresh tumor specimens and the primary cell lines. Furthermore, when levels of activated p21 ras were decreased in astrocytoma cells expressing the ras inhibitory Asn-17 dominant-negative mutant, levels of neurofibromin expression decreased. In addition, fibroblasts induced to express oncogenic activated p21-ras(val12) had increased expression of NF1. These results suggested that neurofibromin expression is increased in human astrocytic tumors as a result of positive feedback regulation by increased levels of activated p21-ras.

Acute presentation of a neurogenic sarcoma in a patient with neurofibromatosis type 1: a pathological and molecular explanation. Case report

Neurofibromatosis type 1 (NF1) is the most common familial cancer-predisposing syndrome in humans, for which the gene (NF1) and its gene product (neurofibromin) have been identified. The majority of tumors occurring in patients with NF1 are benign neurofibromas, sarcomatous transformation is uncommon and most often occurs within the larger plexiform neurofibromas. Such malignant transformation in a known neurofibroma is often heralded by either radiological evidence of growth or a progression in clinical symptoms (pain and neurological deficit). This progression in symptoms is usually gradual in onset, typically occurring over a period of months. In this report the authors document a neurogenic sarcoma presenting with rapid clinical and radiological growth. The pathological basis of this acute presentation was increased cellular proliferation, with invasion of blood vessels resulting in tumor infarction. The molecular basis of neurofibroma development in NF1 is loss of expression of the NF1 gene and its gene product, neurofibromin, resulting in elevated levels of Ras-guanosine triphosphate. Subsequent molecular events result in sarcomatous transformation.

Ras-GTP levels are elevated in human NF1 peripheral nerve tumors

Neurofibromin, the gene product of NF1, is a Ras GTPase Activating Protein. The absence of neurofibromin leads to increased levels of Ras-GTP, which contributes to the proliferation of NF1 neurogenic sarcoma cell lines. Whether this pathogenic mechanism is applicable to benign and malignant peripheral nerve tumours from NF1 and non NF1 patients is not known, due to lack of a tissue based assay. We have adapted a colorimetric enzymatic assay for determining levels of Ras bound guanine nucleotides in tissues. Ras-GTP levels were increased in NF1 neurogenic sarcomas (15 times) and benign NF1 neurofibromas (four times), compared to non NF1 schwannomas. Neurofibromin was not expressed in NF1 sarcomas, in support of its important negative Ras regulatory role in the pathogenesis of NF1 peripheral nerve tumors.

Pediatric pain management (Part II)

This article is the second in a two-part series on pediatric pain management. It primarily contains information about the use of narcotic analgesics for pediatric patients.

Pediatric pain management (Part I)

This article is the first in a two-part series on pediatric pain management. It contains primarily a general discussion of pediatric pain, myths and misconceptions about pediatric pain, and the use of nonnarcotic analgesics for pain control. In the second article, the use of narcotic analgesics for the pediatric population will be discussed.

Nursing care of pituitary surgery: an example of advanced clinical practice

Because we have one of the leading pituitary surgeons in Canada, Dr. Harley Smyth, on our neurosurgical service we have nursed over 53f cases of pituitary tumor resection at the Wellesley Hospital. This series of patients represents a major ongoing international research project in Endocrinology and Neurosurgery and involves close teamwork between these two services and the nursing service. The paper gives a brief overview of pituitary surgery from its beginnings with Sir Victor Horsley in 1904 and details major breakthroughs since the 1960's. The three principal clinical groups of pituitary problems treated at the Wellesley are then outlined. The preoperative work-up on the endocrinology ward delineating clinical symptoms and precise hormonal values, the operation with the new anatomical approach developed by Dr. Smyth, and postoperative care with precise monitoring of fluid and electrolyte balance, methods of nasal packing, treatment of cerebrospinal fluid leaks and tracking of hormone levels are all examined in detail. We explain new developments such as the move to less steroid coverage and the better understanding of the ultrastructure and functional microbiology of pituitary tumors. We conclude by pointing out the excellent management of these patients, with a short hospital stay and much of the preoperative work-up done on an outpatient basis. As well these patients are an extremely satisfying group to nurse because of the high correction rate achieved. Finally, as nursing protocols constantly change and as we continually learn more from this research project, we emphasize the need for the flexibility and knowledge of the advanced nursing practitioner.

Measurement of brain tissue density using pycnometry

A novel method to measure specific gravity (SG) of tissues, pycnometry (PYC), is described. This method utilizes a 2ml glass pycnometer filled with distilled H2O to determine the displacement volume of a tissue sample and an equation to compute SG from the sample's weight and the pycnometer's weight before and after adding the sample. The PYC method was validated using glass SG standards over the range 1.02-1.26, and against the column density gradient (DG) method using brain tissue from 250-300 g male rats. Factors which affect PYC accuracy, i.e. sample size, were also evaluated. Our results indicate that PYC SG values are highly correlated with the glass SG standards (slope = 1.0107, r = 0.9955, p less than 0.001), and highly correlated with DG when approximately 0.120 ml tissue samples are used in the pycnometer. The DG method was preferable to the PYC method, however, when small tissue samples, i.e. 0.60 ml or less, were used.

An animal model of epidural compression of the spinal cord

A new model of subacute compression of the spinal cord is described. Using an expanding epidural mass, a gradual, progressive, and highly reproducible neurological deficit was induced in rats over a 7-day period, resulting in paraplegia. Studies of spinal cord edema, disruption of the blood-spinal cord barrier, and somatosensory evoked responses, as well as histopathological and microangiographical studies, revealed a marked similarity to changes produced in other spinal compression models and in humans. The model may serve to answer some fundamental questions regarding the pathophysiology and efficacy of various treatment modalities of spinal cord compression.

Optimal reuse of cuprammonium rayon hollow-fibre dialyzers

The optimal number of times a hollow-fibre cuprammonium rayon (Terumo TAF) dialyzer could be used was determined in twelve patients. Each dialyzer was reused six times. There was a highly significant decrease in neutrophil count (46.9 +/- 6.9%, mean +/- s.e.m.), platelet count (9.6 +/- 3.8%, mean +/- s.e.m.) and serum C3 concentration (10.25 +/- 2.4%, mean +/- s.e.m.) 30 minutes after the commencement of dialysis The intensity of these changes decreased with the re-use of the dialyzers up to the fourth time. There was a small, but significant increase in serum beta 2-microglobulin concentrations after a 6-hour dialysis. The difference between pre- and post-dialysis serum beta 2-microglobulin concentrations appeared to be greater during the 5th and the 6th use (18.8% and 20.5% vs 5.0% during the first use). The clearance rates of urea and creatinine showed a trend to decrease from the fourth use onwards and the ultrafiltration coefficient was significantly reduced from the third use (8.5 +/- 4.0 mean +/- s.e.m.) onwards so that at the sixth use it was only 75.8 +/- 4.8%, (mean +/- s.e.m.) of the value at the first use. It is concluded that the optimal number of uses a cuprammonium rayon hollow-fibre dialyzer can be put to is four.

High dose versus low dose dexamethasone in experimental epidural spinal cord compression

A compound of methylcellulose-silicone expanding progressively over a 1-week period by moisture absorption was implanted in the midthoracic epidural space of 17 Sprague Dawley adult rats. When the animals became paraplegic 6.3 +/- 1.6 days later, they were randomized into three groups: untreated control (n = 5), high dose dexamethasone (HD, 1.25 mg/kg intramuscularly, twice daily, n = 5), and low dose dexamethasone (LD, 0.125 mg/kg intramuscularly, twice daily, n = 7). Motor strength was evaluated daily by an observer unaware of the treatment given to the rats. Animals treated with dexamethasone (HD or LD) improved faster than untreated control animals. No significant difference in the rate of recovery or degree of motor improvement was noted between the HD and LD groups. Mortality was higher in the HD group because of infections and gastrointestinal perforation/bleeding.