An orchestrated gene expression component of neuronal programmed cell death revealed by cDNA array analysis

Programmed cell death (PCD) during neuronal development and disease has been shown to require de novo RNA synthesis. However, the time course and regulation of target genes is poorly understood. By using a brain-biased array of over 7,500 cDNAs, we profiled this gene expression component of PCD in cerebellar granule neurons challenged separately by potassium withdrawal, combined potassium and serum withdrawal, and kainic acid administration. We found that hundreds of genes were significantly regulated in discreet waves including known genes whose protein products are involved in PCD. A restricted set of genes was regulated by all models, providing evidence that signals inducing PCD can regulate large assemblages of genes (of which a restricted subset may be shared in multiple pathways).

Developmental regulation of neurogenesis in the pluripotent human embryonal carcinoma cell line NTERA-2

Embryonal carcinoma (EC) cells provide a caricature of pluripotent embryonic stem (ES) cells and may be used as surrogates for investigating the mechanisms that regulate cell differentiation during embryonic development. NTERA-2 is a human EC cell line that differentiates in response to retinoic acid yielding cells that include terminally differentiated neurons. The expression of genes known to be involved in the formation of the vertebrate nervous system was examined during retinoic acid-induced NTERA-2 differentiation. Differentiation of these human EC cells into neurons could be divided into three sequential phases. During phase 1, in the first week of differentiation, hath1 mRNA showed a small transient increase that correlated with the rapid accumulation of nestin message, a marker of neuroprogenitors. Transcripts of nestin were quickly downregulated during phase 2 as expression of neuroD1, characteristic of neuroprogenitors exiting the cell cycle, was induced. A neural cell surface antigen, detected by the monoclonal antibody A2B5, was expressed by cells exiting the cell cycle, correlating with the expression of neuroD1 as the cells became post-mitotic. Markers of mature neural cells (e.g. synaptophysin and neuron-specific enolase) were subsequently increased during phase 3 and were maintained. This regulated pattern of gene expression and commitment to the neural lineage indicates that differentiation of NTERA-2 neurons in vitro follows a similar pathway to that observed by neural ectodermal precursors during vertebrate neurogenesis in vivo.

Regulation of Tiam1 nucleotide exchange activity by pleckstrin domain binding ligands

Rho family GTPases play roles in cytoskeletal organization and cellular transformation. Tiam1 is a member of the Dbl family of guanine nucleotide exchange factors that activate Rho family GTPases. These exchange factors have in common a catalytic Dbl homology and adjacent pleckstrin homology domain. Previous structural studies suggest that the pleckstrin domain, a putative phosphoinositide-binding site, may serve a regulatory function. We identified ascorbyl stearate as a compound that binds to the pleckstrin domain of p120 Ras GTPase-activating protein. Furthermore, ascorbyl stearate appears to be a general pleckstrin domain ligand, perhaps by mimicking an endogenous amphiphilic ligand. Tiam1 nucleotide exchange activity was greatly stimulated by ascorbyl stearate. Certain phosphoinositides also stimulated Tiam1 activity but were less potent than ascorbyl stearate. Tiam1 contains an additional N-terminal pleckstrin domain, but only the C-terminal pleckstrin domain was required for activation. Our results suggest that the pleckstrin domains of Dbl-type proteins may not only be involved in subcellular localization but may also directly regulate the nucleotide exchange activity of an associated Dbl homology domain. In addition, this paper introduces ascorbyl stearate as a pleckstrin domain ligand that can modulate the activity of certain pleckstrin domain-containing proteins.

Percutaneous dilatational tracheostomy: haemorrhagic complications and the vascular anatomy of the anterior neck. A review based on 497 cases

In a series of 497 PDT procedures done in the intensive therapy unit at Morriston Hospital between 1992 and 1999, PDT was abandoned because of bleeding in 6 patients and was noted to be a problem in a further 18 cases (overall incidence 4.8%). In all cases, haemorrhage was successfully arrested. Surgical tracheostomy was necessary in 6 of these 24 cases. The source of bleeding in 4 of these patients was attributed to the inferior thyroid vein (2 cases), high brachiocephalic vein, and possibly an aberrant anterior jugular communicating vein, respectively. In one patient, the vessel presumed injured could not be identified and in another patient, bleeding was related to multi-system disease. We conclude that the risk of bleeding, although low, can be minimised if the operator maintains a high index of suspicion for aberrant vascular anatomy and investigates possible abnormalities with diagnostic ultrasound. Injury to vessels low in the neck can be reduced by not fully extending the neck and siting the stoma at the upper tracheal rings. The possibility of developing a tracheoarterial fistula is reduced if the stoma is situated above the 4th tracheal ring and fibreoptic endoscopy is used to confirm correct tracheostomy tube placement.

Population-based study of the pattern of molecular markers of minimal residual disease in childhood and adult acute lymphoblastic leukemia: an assessment of the practical difficulty of representative sampling for trial purposes. Northern Region Haematology Group

BACKGROUND

The prevalence, in unselected patients with acute lymphoblastic leukaemia (ALL), of clonal rearrangements suitable for minimal residual disease (MRD) studies has not been formally investigated.

PROCEDURE

This was a prospective, demographic study of the frequency of molecular markers of MRD in all patients with ALL presenting over 5 years within the Northern Health Region of England (population 3.1 million). Presentation marrow samples were examined to detect informative markers.

RESULTS

One hundred twenty-four children (age <15 years) developed non-Burkitt ALL. No material was available for study in 21. Eighty-six had clonal gene rearrangements (BCR/ABL, immunoglobulin heavy chain (IGH) and/or T cell receptor (TCR) gene rearrangements). All entered remission; 84 (68% of the original cohort) survived to become eligible for MRD studies. One hundred sixteen adults developed ALL, of whom 48 were not studied due to insufficient cellular material in the bone marrow aspirate or to logistical problems in central referral of samples from other hospitals. Material from elderly adults (age >55 years) was less likely to be sent for analysis, 36% vs. 59% (P = 0.024). Thirty-eight had BCR/ABL and/or IGH/TCR gene rearrangements. Thirty-one (27% of the original cohort) entered remission and became eligible for MRD studies. Informative gene rearrangements were more common in children than adults (83% vs. 63%, P < 0.003).

CONCLUSIONS

The results reveal substantial potential, unintentional, selection bias. Large-scale multicentre studies of MRD in children may well produce clinically relevant and representative data. Those who mount similar studies in adults should not assume they will be similarly representative or as successful in accrual of material.

Orf virus encodes a novel secreted protein inhibitor of granulocyte-macrophage colony-stimulating factor and interleukin-2

The parapoxvirus orf virus encodes a novel soluble protein inhibitor of ovine granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-2 (IL-2). The GM-CSF- and IL-2-inhibitory factor (GIF) gene was expressed as an intermediate-late viral gene in orf virus-infected cells. GIF formed homodimers and tetramers in solution, and it bound ovine GM-CSF with a K(d) of 369 pM and ovine IL-2 with a K(d) of 1.04 nM. GIF did not bind human GM-CSF or IL-2 in spite of the fact that orf virus is a human pathogen. GIF was detected in afferent lymph plasma draining the skin site of orf virus reinfection and was associated with reduced levels of lymph GM-CSF. GIF expression by orf virus indicates that GM-CSF and IL-2 are important in host antiviral immunity.

RADARx: Recognizing, Assessing, and Documenting Adverse Rx events

BACKGROUND

Adverse events are a leading cause of morbidity and mortality. Adverse Drug Events (ADEs) are frequent, under-reported, costly, and largely preventable. Computerized tools expose effectively ADEs and can reduce their impact.

METHODS

RADARx is a Veterans Administration (VA) VistA-compatible M software program that integrates computerized ADE screening, probability assessment, documentation, and reporting capabilities. Data dictionary mapping tools have enabled RADARx implementation at 3 sites. All RADARx alerts generated at VA Medical Center (VAMC) Nashville from 7/1/99 to 9/30/99 were evaluated.

RESULTS

Total ADEs documented using RADARx numbered 57. RADARx discovered 34 ADEs and 48 'potential' ADEs; 23 ADEs were found using traditional means. Overall, 11% of RADARx alerts were true positives. Pharmacist review of the 8-20 alerts generated daily costs between 10 and 30 minutes.

Rating the appropriateness of coronary angiography, coronary angioplasty and coronary artery bypass grafting: the ACRE study. Appropriateness of Coronary Revascularisation study

BACKGROUND

Previous studies investigating the appropriateness of invasive management of coronary disease had not reported the internal consistency of their ratings and may now be out of date. The aim of this study was to measure the influence of clinical factors on contemporary ratings of the appropriateness of coronary angiography, percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass graft (CABG) in the Appropriateness of Coronary Revascularisation (ACRE) study.

METHODS

The Delphi-RAND technique was used, in which an expert panel (four cardiologists, three cardiothoracic surgeons, a general physician and a general practitioner), meeting in 1995, rated mutually exclusive indications (n = 2178 for angiography, n = 995 for PTCA and n = 984 for CABG). The main outcome measures were the appropriateness category (inappropriate, uncertain or appropriate) for each of the three procedures and treatment preference.

RESULTS

For revascularization, the strongest determinant of inappropriateness was coronary anatomy. The odds ratio (OR) for inappropriate PTCA was 10.6 (95 per cent confidence interval (CI) 4.8-23.5) for the effect of left main stem or three-vessel disease versus single-vessel disease, and for CABG it was 0.06 (95 per cent CI 0.03-0.15). The number of diseased vessels was strongly related to preference for medical, PTCA or CABG treatment (p for linear trend <0.001). Mild versus severe anginal symptoms were associated with inappropriate angiography (OR 2.0 (95 per cent CI 0.9-9.8), although this effect was stronger when only the cardiologists' ratings were considered (OR 10.1 (95 per cent CI 2.4-42.6)).

CONCLUSION

These are the first UK ratings of appropriateness covering all three procedures. The associations with clinical factors provide evidence of the internal consistency of these ratings. Prospective validation of these ratings against clinical outcomes is under way in the ACRE study.

Effect of oral rotavirus/iscom vaccines on immune responses in gnotobiotic lambs

A comparison of the effect on the immune responses in gnotobiotic lambs was made between an iscom vaccine prepared from recombinant rotavirus VP6 protein, an inactivated rotavirus/iscom-matrix vaccine and a vaccine comprising inactivated rotavirus alone. All three vaccines induced immunological priming and some degree of protection was observed after a single oral dose. However, different immune responses were induced in response to a virulent infection. The group vaccinated with the rotavirus/iscom-matrix vaccine showed a Th2-like response characterised by rotavirus-specific antibodies and a down-regulation of IFNgamma in jejunal Peyer's patches. Both Th1-like and Th2-like immune responses were induced in the group receiving the VP6 vaccine as seen by significantly increased expressions of IFNgamma and IL-6 in the jejunal Peyer's patch together with an increased percentage of CD8+ T cells in the intestine and rotavirus-specific antibodies at mucosal surfaces. Iscom vaccines given orally have the ability to induce both Th1-like and Th2-like immune responses in a ruminant model.

A comparison of the effects of olanzapine, haloperidol and placebo on cognitive and psychomotor functions in healthy elderly volunteers

The cognitive and psychomotor effects of olanzapine (3 mg) were compared with haloperidol (3 mg) and placebo in a double-blind, cross-over study. Fourteen healthy elderly volunteers (>65 years) were randomized to receive once daily medication for 4 days with a 16-day interval between treatment periods. Assessments of attention, memory and motor control were made prior to dosing on each day, at 2, 4, 6 and 8 h after dosing on days 1 and 4, and at 24 and 48 h following the last dose. On day 1, detectable impairment was observed at all time points in both groups. On day 4, haloperidol treated subjects showed increased impairment compared with day 1 and this was sustained throughout the 48 h of testing. Olanzapine treated subjects showed reduced day 4 deficit (compared with day 1), with no significant difference from placebo beyond 6 h post dose. These results suggest that both haloperidol and olanzapine have a measurable initial effect on cognitive and psychomotor function in elderly volunteers. However, acute effects associated with olanzapine decrease with repeated dosing and show substantial adaptation within 4 days. In contrast, effects seen with haloperidol are sustained and increase with repeated dosing over the same period.

An in vivo analysis of the effectiveness of the osteoarthritic knee brace during heel-strike of gait

The objective of this study was to analyze the effects of off-loading knee braces in patients diagnosed with symptomatic unicompartmental osteoarthritis. Under fluoroscopic surveillance, 15 patients were asked to perform normal gait on a treadmill. Each patient was asked initially to walk without using a knee brace and then to walk while wearing a brace. The fluoroscopic images of the patients at heel-strike were downloaded to a workstation computer. Condylar separation angle of the knee joint and the distances from the medial and lateral femoral condyles to the tibial plateau (condylar separation) were measured. Twelve of 15 patients (80%) reported relief of pain and demonstrated condylar separation of the degenerative compartment with the use of the off-loading brace. The 3 patients who did not demonstrate condylar separation were obese, making accurate brace fitting difficult. The average change in condylar separation and condylar separation angle was 1.2 mm (range, 0.0-4.5 mm) and 2.2 degrees (range, 0.0 degrees-7.8 degrees). This study demonstrated that condylar separation of a degenerative knee compartment can be achieved with off-loading braces with subsequent subjective relief of knee pain.

Antitumor efficacy of AG3340 associated with maintenance of minimum effective plasma concentrations and not total daily dose, exposure or peak plasma concentrations

Oral administration of AG3340, a novel metalloprotease (MMP) inhibitor, suppresses the growth of human colon adenocarcinoma (COLO-320DM) tumors in vivo (Proc Am Assoc Cancer Res 39: 2059, 1998). In this report, we tested the hypothesis that the growth inhibition of these tumors is associated with maintaining minimum effective plasma concentrations of AG3340. Nude mice were given a total oral daily dose of 25 or 200 mg/kg; 6.25 mg/kg was given four times per day (QID) (25 mg/kg/day), and 100 mg/kg was given in two daily doses (BID) (200 mg/kg/day). Peak plasma concentrations (Cmax) of 83 +/- 43 (mean +/- SD) and 1998 +/- 642 ng/ml were detected 30 min after a single dose with 6.25 mg/kg and 100 mg/kg AG3340, respectively. AUC(0-24 h) values estimated from dosing with 25 and 200 mg/kg/day AG3340 were 672 and 10882 ng*h/ml, respectively. Importantly, both regimen inhibited tumor growth equivalently (74 to 82%). Efficacy was also compared at a total daily dose of 25 mg/kg by giving AG3340: QID (6.25 mg/kg per dose), BID (12.5 mg/kg per dose), and once daily (25 mg/kg per dose). The Cmax of these regimens was 83 +/- 43, 287 +/- 175 and 462 +/- 495 ng/ml, respectively. AG3340 did not inhibit tumor growth with the latter two regimens. The efficacy of 6.25 mg/kg QID (25 mg/kg/day) was superior to the efficacy of 25 mg/kg BID (50 mg/kg/day), substantiating the independence of efficacy from the total daily dose and Cmax. Expectedly, peak to trough fluctuations were significantly smaller with the QID regimen than with BID and QD dosing. After 24 h, the trough was greater than 1 ng/ml with QID dosing but was less than 1 ng/ml after QD and BID dosing. These results suggest that the antitumor efficacy of AG3340 was associated with maintaining minimum effective plasma concentrations of AG3340 and demonstrate that the antitumor efficacy of AG3340 was independent of the total daily dose, peak plasma concentration, and drug exposure in this tumor model.

Broad antitumor and antiangiogenic activities of AG3340, a potent and selective MMP inhibitor undergoing advanced oncology clinical trials

We studied AG3340, a potent metalloproteinase (MMP) inhibitor with pM affinities for inhibiting gelatinases (MMP-2 and -9), MT-MMP-1 (MMP-14), and collagenase-3 (MMP-13) in many tumor models. AG3340 produced dose-dependent pharmacokinetics and was well tolerated after intraperitoneal (i.p.) and oral dosing in mice. Across human tumor models, AG3340 produced profound tumor growth delays when dosing began early or late after tumor implantation, although all established tumor types did not respond to AG3340. A dose-response relationship was explored in three models: COLO-320DM colon, MV522 lung, and MDA-MB-435 breast. Dose-dependent inhibitions of tumor growth (over 12.5-200 mg/kg given twice daily, b.i.d.) were observed in the colon and lung models; and in a third (breast), maximal inhibitions were produced by the lowest dose of AG3340 (50 mg/kg, b.i.d.) that was tested. In another model, AG3340 (100 mg/kg, once daily, i.p.) markedly inhibited U87 glioma growth and increased animal survival. AG3340 also inhibited tumor growth and increased the survival of nude mice bearing androgen-independent PC-3 prostatic tumors. In a sixth model, KKLS gastric, AG3340 did not inhibit tumor growth but potentiated the efficacy of Taxol. Importantly, AG3340 markedly decreased tumor angiogenesis (as assessed by CD-31 staining) and cell proliferation (as assessed by bromodeoxyuridine incorporation), and increased tumor necrosis and apoptosis (as assessed by hematoxylin and eosin and TUNEL staining). These effects were model dependent, but angiogenesis was commonly inhibited. AG3340 had a superior therapeutic index to the cytotoxic agents, carboplatin and Taxol, in the MV522 lung cancer model. In combination, AG3340 enhanced the efficacy of these cytotoxic agents without altering drug tolerance. Additionally, AG3340 decreased the number of murine melanoma (B16-F10) lesions arising in the lung in an intravenous metastasis model when given in combination with carboplatin or Taxol. These studies directly support the use of AG3340 in front-line combination chemotherapy in ongoing clinical trials in patients with advanced malignancies of the lung and prostate.

The prevention of corticosteroid-induced bone loss with intermittent cyclical etidronate

A prospective, randomised, double-blind, placebo controlled primary prevention trial was undertaken in 28 patients commencing low to moderate doses of corticosteroids for the first time. Patients were randomised to intermittent cyclical etidronate (400 mg daily for 2 weeks) and calcium (500 mg daily for 11 weeks) or intermittent cyclical placebo with calcium. After 52 weeks of treatment, lumbar spine BMD increased by 1.8% in the etidronate group, while it decreased by 3.7% in the placebo group. The differences in bone loss rate were statistically significant (p<0.01) at both 6 and 12 months. Similar trends were observed at the proximal femur, but differences were not statistically significant. These results suggest that intermittent cyclical etidronate therapy is effective in the primary prevention of corticosteroid-induced bone loss at the lumbar spine.

Changes in neuron size in cynomolgus macaques infected with various immunodeficiency viruses and poliovirus

Human immunodeficiency virus (HIV) infection leads to clinically significant neuronal pathology, but the underlying mechanism remains unclear. Infection of rhesus macaques with the simian immunodeficiency virus SIVmac251 has been shown to cause atrophy of hippocampal pyramidal cells. The aim of the current investigation was to determine whether SIVmac251 and other viruses with differing abilities to cause immune suppression or encephalitis could cause neuronal atrophy in cynomolgus macaques. Animals infected with SIVmac251 (n = 22), HIV-2 (n = 6). SIVmac239 (n = 7) and poliovirus (n = 10) were investigated, together with 16 controls. Hippocampal pyramidal cell diameter, averaged across the four CA subfields, was reduced by 16.6% in the SIVmac251 group (P < 0.0001) and by 13.3% in the HIV-2 group (P < 0.001), even though the latter virus does not generally cause immunosuppression. Conversely, SIVmac239, which does cause immunosuppression, caused an average neuronal hypertrophy of 6.8% (P = 0.033). Of possible relevance to the different behaviour of the two SIVs is that SIVmac239 is lymphocyte tropic and does not infect CNS microglia in vivo whereas SIVmac251 does. Animals inoculated with poliovirus into the lumbar spinal cord for polio vaccine neurovirulence testing acted as positive controls for CNS inflammation and they also showed an increase in neuronal diameter (4.1%, P = 0.025). The atrophy seen with SIVmac251 and HIV-2 involved all CA subfields but the hypertrophy following SIVmac239 or poliovirus infection was restricted to CA1 and CA2. These observations show a dissociation between the ability of immunodeficiency viruses to cause immune suppression and neuronal pathology and demonstrate that CNS inflammation per se may cause neuronal hypertrophy.

Enhanced neuronal differentiation of NTera-2 cells expressing neuronally restricted beta2 adrenergic receptor

NTera-2/D1 (NT2) is a human teratocarcinoma cell line which can be cultured as a dividing population of precursor cells that can be manipulated with retinoic acid (RA) to yield post-mitotic neurons. Precursor cells were transfected with the human beta2 adrenergic receptor, controlled by the neuronal cell specific rat synapsin-1 promoter. Transfected precursor cells did not display elevated expression of the beta2 adrenergic receptor. Upon differentiation to a neuronal phenotype with RA, betaSyn2 and betaSyn4 (beta2Syn-NT2; ATCC CRL-12356) displayed elevated beta2 adrenergic receptor levels, and an elevated coupling to cAMP production. It was also observed that the elevated expression of the beta2 adrenergic receptor in the neuronal NT2 cells resulted in an enhanced level of neuronal differentiation compared to the wild type cells. These results demonstrate that the neuronally restricted expression of the human beta2 adrenergic receptor in NT2 neurons results in increased receptor levels and receptor stimulated generation of cAMP, this may result in the observed improvement in neuronal differentiation.

Absent pulmonary valve syndrome with interrupted aortic arch

A surgically treated case of absent pulmonary valve syndrome associated with type B interrupted aortic arch is presented. The presence of a restrictive ductus arteriosus promoted the development of a collateral circulation between ascending and descending thoracic aorta, allowing the child to remain clinically stable after birth.

Contagious bovine pleuropneumonia. The costs of control in Central/southern Africa

Contagious bovine pleuropneumonia (CBPP) caused by Mycoplasma mycoides subspecies mycoides small colony (M. mycoides) has been endemic in many parts of Africa for the greater part of this century. Because of an international vaccination campaign the disease was almost eliminated from the continent. With the deteriorating economic situation of many countries, vaccination programs have been allowed to slip; drought conditions have resulted in great movements of livestock and the disease has spread rapidly to the east and south. For Government Veterinary Departments, the implications of this resurgence of CBPP, are serious. The costs threaten to overwhelm completely under-funded government, services. Where cost-recovery measures are introduced, the charging for vaccines may damage rapport with communities and erode the credibility of the government services. Farmers may find the loss of cattle and the costs of vaccine severe burdens which threaten their livelihoods and social well-being (Zambia) and even, in extreme cases, their survival (Botswana). Controlling the disease today presents new possibilities which include increased cross-border collaboration (Malawi/Tanzania), increased emphasis on monitoring (N. Zambia) and the greater involvement of communities in disease control (W. Zambia).

Periaortic fat pad mimicking an intramural hematoma of the thoracic aorta: lessons for transesophageal echocardiography

We report a patient whose clinical and echocardiographic findings were compatible with a diagnosis of aortic intramural hematoma, but magnetic resonance imaging demonstrated a prominent and localized periaortic deposit of fat as the cause of the transesophageal echocardiographic appearance. This is a significant caveat that must be borne in mind when interpreting echocardiographic images obtained in patients with suspected intramural aortic hematomas.

The action of three antiseptics/disinfectants against enveloped and non-enveloped viruses

The antiviral action of chloroxylenol, benzalkonium chloride and cetrimide/chlorhexidine was assessed against a range of enveloped and non-enveloped human viruses using a suspension test method. Viral suspensions of 10(6)-10(7) pfu/TCID50 or sfu were prepared in each of the antiseptic/disinfectant solutions in the presence of a bovine serum/yeast extract mixture to simulate 'dirty conditions'. During incubation, aliquots were removed at predetermined timepoints up to 10 min to assess the kinetics of inactivation. Results indicate that all products were effective in inactivating the enveloped viruses herpes simplex virus type 1 and human immunodeficiency virus type 1, whilst being ineffective in inactivating human coronavirus, also enveloped, and the non-enveloped viruses. The exception to this was the benzalkonium chloride-based product (Dettol Hospital Concentrate) which was active against the non-enveloped human coxsackie virus. Four antiseptic/disinfectant solutions with chloroxylenol, benzalkonium chloride, cetrimide/chlorhexidine and povidone-iodine were also assessed for antiviral effect against human immunodeficiency virus in the presence of whole human blood. All four solutions proved to be effective within 1 min despite the cytotoxic nature of the compounds to the detection system.