A Ras protein from a phytopathogenic fungus causes defects in hyphal growth polarity, and induces tumors in mice

Ras is a low-molecular-weight guanine nucleotide (GDP/GTP)-binding protein that transduces signals for growth and differentiation in eukaryotes. In mammals, the importance of Ras in regulating growth is underscored by the observation that activating mutations in ras genes are found in many animal tumors. Colletorichum trifolii is a filamentous fungal pathogen of alfalfa which causes anthracnose disease. To investigate signaling pathways that regulate growth and development in this fungus, a gene encoding a Ras homolog (CT-Ras) was cloned from C. trifolii. CT-Ras exhibited extensive amino acid similarity to Ras proteins from higher and lower eukaryotes. A single amino acid change resulting in mutationally activated CT-Ras induced cellular transformation of mouse (NIH 3T3) fibroblasts and tumor formation in nu/nu mice. In Colletotrichum, mutationally activated CT-Ras induced abnormal hyphal proliferation and defects in polarized growth, and significantly reduced differentiation in a nutrient-dependent manner. These results show that C. trifolii Ras is a functional growth regulator in both mammals and fungi, and demonstrate that proper regulation of Ras is required for normal fungal growth and development.

The use of the laryngeal mask airway for inter-hospital transport of infants with type 3 laryngotracheo-oesophageal clefts

Type 3 laryngotracheo-oesophageal clefts are rare congenital anomalies with a high mortality. In the past, transport of such infants to tertiary centres for surgical correction has proved extremely difficult, with the child's ventilatory status often deteriorating to such an extent that ultimate surgical intervention has not proved possible. We describe two cases of successful inter-hospital transfer of infants with type 3 laryngotracheo-oesophageal clefts using the laryngeal mask airway.

Fumonisin B1, a mycotoxin contaminant of cereal grains, and inducer of apoptosis via the tumour necrosis factor pathway and caspase activation

Fumonisins are mycotoxins produced by Fusarium moniliforme, a prevalent fungus which infects corn or other cereal grains. Fumonisin B1 (FB1) is the most common mycotoxin produced by F. moniliforme, suggesting that it has toxicological significance. The structure of FB1 resembles sphingoid bases and it inhibits ceramide synthase. As sphingoid bases regulate cell growth, differentiation, transformation and apoptosis, it is reasonable to hypothesize that FB1 can also regulate these activities. Previous studies concluded that FB1 induced apoptosis or cell-cycle arrest in CV-1 cells (African green monkey kidney fibroblasts). In this study, we have identified genes that inhibit FB1-induced apoptosis in CV-1 cells and in two primary human cell types (lung fibroblasts and neonatal kidney cells). A baculovirus gene. inhibitor of apoptosis (IAP), protected CV-1 and the human cells from apoptosis. IAP blocks apoptosis which is induced by the tumour necrosis factor (TNF) pathway. Inhibition of interleukin converting enzymes (ICE proteases or caspases) by the baculovirus gene p35 also inhibited FB1-induced apoptosis. FB1 treatment led to cleavage of Rb (retinoblastoma protein) at its C-terminus in CV-1 or human lung cells. As the C-terminus of Rb is cleaved by ICE proteases during apoptosis, this supports an active role for ICE proteases in FB1-induced apoptosis. The tumour suppressor gene p53 was not required for FB1-induced apoptosis because p53-/- primary mouse embryo fibroblasts underwent apoptosis following FB1 treatment. Furthermore, Bcl-2 was not an effective inhibitor of FB1-induced apoptosis in CV-1 or IMR-90 cells. In summary, these results demonstrate that the TNF pathway and caspases plays an important role in FB1-induced apoptosis.

Population pharmacokinetics. A regulatory perspective

The application of population approaches to drug development is recommended in several US Food and Drug Administration (FDA) guidance documents. Population pharmacokinetic (and pharmacodynamic) techniques enable identification of the sources of inter- and intra-individual variability that impinge upon drug safety and efficacy. This article briefly discusses the 2-stage approach to the estimation of population pharmacokinetic parameters, which requires serial multiple measurements on each participant, and comprehensively reviews the nonlinear mixed-effects modelling approach, which can be applied in situations where extensive sampling is not done on all or any of the participants. Certain preliminary information, such as the compartment model used in describing the pharmacokinetics of the drug, is required for a population pharmacokinetic study. The practical design considerations of the location of sampling times, number of samples/participants and the need to sample an individual more than once should be borne in mind. Simulation may be useful for choosing the study design that will best meet study objectives. The objectives of the population pharmacokinetic study can be secondary to the objectives of the primary clinical study (in which case an add-on population pharmacokinetic protocol may be needed) or primary (when a stand-alone protocol is required). Having protocols for population pharmacokinetic studies is an integral part of 'good pharmacometric practice'. Real-time data assembly and analysis permit an ongoing evaluation of site compliance with the study protocol and provide the opportunity to correct violations of study procedures. Adequate policies and procedures should be in place for study blind maintenance. Real-time data assembly creates the opportunity for detecting and correcting errors in concentration-time data, drug administration history and covariate data. Population pharmacokinetic analyses may be undertaken in 3 interwoven steps: exploratory data analysis, model development and model validation (i.e. predictive performance). Documentation for regulatory purposes should include a complete inventory of key runs in the analyses undertaken (with flow diagrams if possible), accompanied by articulation of objectives, assumptions and hypotheses. Use of diagnostic analyses of goodness of fit as evidence of reliability of results is advised. Finally, the use of stability testing or model validation may be warranted to support label claims. The opinions expressed in this article were revised by incorporating comments from various sources and published by the FDA as 'Guidance for Industry: Population Pharmacokinetics' (see the FDA home page http:/(/)www.fda.gov for further information).

Computed tomographic evaluation and guided correction of malpositioned nephrostomy catheters

BACKGROUND

To determine the utility of computed tomography (CT) in the detection and correction of malpositioned nephrostomy catheters after contrast spillage during nephrostograms.

METHODS

CT was performed in nine patients after an abnormal (contrast spillage) tube nephrostogram performed during or after nephrostomy tube placement. CT was used to locate the nephrostomy catheter position in relation to the renal collecting system. If possible, CT was also used for guidance and repositioning of the nephrostomy catheters into the intrarenal collecting system.

RESULTS

In all nine cases, CT was successful in detecting the position of the suspected malpositioned catheter. In seven of nine cases, CT demonstrated the catheter outside the renal collecting system and effectively helped reposition the catheters into the intrarenal collecting system. In one case, the malpositioned nephrostomy catheter was within the intraperitoneal cavity and required surgical correction. Another case required fluoroscopic-guided repositioning for the initial nephrostomy catheter, which was partly posterior to the kidney and partly within the kidney. The catheter in this latter case was successfully advanced over a guidewire into the collecting system.

CONCLUSIONS

CT may be used to detect possible catheter malposition associated with nephrostomy tube placement. CT may also be used to successfully guide catheter repositioning in the renal collecting system.

Molecular characterisation of cloned bradykinin B1 receptors from rat and human

This report describes the characterisation of cloned rat and human bradykinin B1 receptors in African green monkey kidney fibroblast (Cos-7) cells. A ligand binding assay with [3H]des-Arg10-kallidin was used to compare their pharmacology with respect to known bradykinin B1 and B2 receptor ligands. In addition, the pharmacology of T-kinin and its' derivative des-Arg11-T-kinin was investigated. The cloned rat receptor had a similar pharmacology to that of the recently described mouse receptor and differs from that described for the human receptor. The rat receptor had a higher affinity for des-Arg11-T-kinin than the human receptor. These differences in pharmacological properties may relate to the presence of T-kinin, bradykinin and their des-Arg derivatives as the major physiological peptides in rat and the predominance of kallidin and its derivatives in human. We confirm that the rat bradykinin B1 receptor gene is organised in a two exon structure and differs from the human gene which has a three exon structure and we further examine the inducible expression of this gene in a wide range of tissues using Northern blotting.

T-cell and antibody response characterisation of a new recombinant pre-S1, pre-S2 and SHBs antigen-containing hepatitis B vaccine; demonstration of superior anti-SHBs antibody induction in responder mice

The incidence of non-responders to hepatitis B (HB) virus SHBs antigen (Ag) vaccines has prompted the development of pre-S containing vaccines. The aim of this study was to characterise the murine immune response to a novel recombinant particle (Hepagene) (Medeva plc) containing pre-S1, pre-S2 and SHBsAg components. Hepagene induced potent in vitro spleen T-cell proliferative responses in both BALB/c (maximum stimulation index (SI) = 38) and SWR/J (maximum SI = 43) strains of mouse, following immunisation. High concentrations of interferon-gamma and low concentrations of interleukin-10 were detected in the media of spleen cells stimulated with Hepagene. The anti-Hepagene antibody response was higher in SWR/J mice and alhydrogel adjuvant significantly improved the titres. Anti-pre-S1 antibody was detected in both strains of mouse, whereas antipre-S2 antibody was only detected in SWR/J mice. IgG subclass analysis of the anti-Hepagene response revealed a Th2-type response in BALB/c mice and a mixed Th1/Th2 response in SWR/J mice. Hepagene induced higher anti-SHBs antibody responses than Engerix-B (11097 and 1276 IU/ml, respectively) in BALB/c mice. Hepagene therefore, stimulates strong cellular and humoral immune responses in murine models. The high anti-SHBs antibody response suggests that Hepagene is an improved hepatitis B virus vaccine.

Physico-chemical analysis of Bordetella pertussis antigens

Physico-chemical methods are being developed for use in the control and standardization of acellular pertussis vaccines and their individual components. We have compared native and detoxified preparations of the B. pertussis antigens, pertussis toxin (PT), filamentous haemagglutinin (FHA), and the 69-kDa outer membrane protein (P69) using circular dichroism (CD), fluorescence spectroscopy, SDS-PAGE and FPLC gel filtration chromatography. Upon aldehyde detoxification, PT underwent a large change in its intrinsic fluorescence maximum (8-10 nm red-shift) and a large increase in its apparent size, detected by chromatography. Polyacrylamide gels showed individual subunits of the same apparent molecular weight (M(r)) as well as some polypeptides of higher M(r). FHA also changed conformation (5-nm red-shift in intrinsic fluorescence) upon aldehyde detoxification, with a resultant increase in the M(r)of its major constituent. The P69 protein appeared quite robust to formaldehyde treatment as measured by the same methods. Its near-UV CD spectrum contains a prominent tryptophan band; so this method may be more suitable for observing differences in conformation. We also examined an aluminium-desorbed DTaP preparation by these methods. When used in conjunction with immunochemical and toxicological assays, these methods are informative and useful in the characterization of candidate standards and should be valuable methods for ensuring the consistency of manufactured vaccines.

Sugar, drinks, deprivation and dental caries in 14-year-old children in the north west of England in 1995

OBJECTIVES

To examine associations between dental caries and reported drink consumption.

DESIGN

A cross-sectional caries prevalence study including reported drink consumption.

SETTING

Secondary schools across the former North Western Region of England.

SUBJECTS

A random sample of 6,014, 14-year-old children.

RESULTS

The mean DMFT of the sample was 2.74. The reported mean weekly consumption of cans of carbonated drinks was 5.66, with a range of zero to 42. There was a significant gender difference in drink consumption and a significant correlation between the reported weekly consumption of cans of carbonated drinks and DMFT. Logistic regression analysis showed tea drinkers had a significantly lower DMFT than coffee drinkers and that this effect was independent of the addition of sugar and the number of cans of drink consumed. Reported use of sugar-free carbonated drinks was not associated with better dental health.

CONCLUSIONS

Reported consumption of sugared drinks and carbonated drinks was associated with significantly higher levels of dental caries. Drinking tea was associated with lower levels of caries. Sugar-free drinks were not associated with better dental health.

Gender differences and practice implications of risk factors for frequent hospitalization for heart failure in an urban center serving predominantly African-American patients

To identify the clinical correlates of recurrent heart failure hospitalization in a large urban hospital serving predominately African-American patients, and to provide further insight into modifiable risks for heart failure readmissions, a retrospective period prevalence review of the records of all adult patients admitted with a primary diagnosis of heart failure (International Classification of Diseases-9 code 428.0) between January and December 1995 was performed. The main outcome was the number of heart failure hospitalizations over 12 months. Twelve hundred patients were identified. Mean age was 64 +/- 16 years, 94% were black, 57% were women, and 40% were > or = 65 years old. Ninety-eight percent had a history of systemic hypertension and 55% had uncontrolled hypertension. Other comorbidities were left ventricular (LV) hypertrophy (64%), coronary artery disease (52%), and tobacco abuse (28%). Sixty-five percent of patients were on angiotensin-converting enzyme (ACE) inhibitors, 51% on calcium antagonists, and 8% on beta blockers. Most patients had suboptimal dosing of ACE inhibitors and there was inappropriate use of calcium antagonists in 56% of patients with moderate or severe systolic dysfunction. Diabetes mellitus and echocardiographic wall motion abnormality were independently associated with frequent admissions for women but not for men. Medication-related increase in heart failure hospitalization was seen for calcium antagonists in patients with severe LV dysfunction (odds ratio 2.24, 95% confidence intervals 1.0 to 5.03; p <0.03). Uncontrolled hypertension, underdosing of ACE inhibitors, and overuse of calcium antagonists in patients with significant LV dysfunction are potential targets for intervention.

Is amoxapine an atypical antipsychotic? Positron-emission tomography investigation of its dopamine2 and serotonin2 occupancy

BACKGROUND

All currently available atypical antipsychotics have, at clinically relevant doses: i) high serotonin (5-HT)2 occupancy; ii) greater 5-HT2 than dopamine (D)2 occupancy; and iii) a higher incidence of extrapyramidal side effects when their D2 occupancy exceeds 80%. A review of pharmacologic and behavioral data suggested that amoxapine should also conform to this profile; therefore, we undertook a positron-emission tomography (PET) study of its 5-HT2 and D2 occupancy.

METHODS

Seven healthy volunteers received 50-250 mg/day of amoxapine for 5 days and then had [11C]-raclopride and [18F]-setoperone PET scans.

RESULTS

5-HT2 receptors showed near saturation at doses of 100 mg/day and above. The D2 receptor occupancies showed a dose-dependent increase, never exceeding 80%; at all doses 5-HT2 occupancy exceeded D2 occupancy.

CONCLUSIONS

PET data show that amoxapine's profile is very similar to that of the established atypical antipsychotics. These data, together with amoxapine's in vitro pharmacologic profile, effectiveness in animal models, and efficacy in psychotic depression raise the possibility of amoxapine as an "atypical" antipsychotic agent in the treatment of schizophrenia.

The mycotoxin fumonisin B1 transcriptionally activates the p21 promoter through a cis-acting element containing two Sp1 binding sites

Fumonisin B1 (FB1) is a food-borne mycotoxin produced by Fusarium moniliforme. Structurally FB1 resembles sphingoid bases, and ingestion of FB1 causes several animal diseases. FB1 will cause hepatic carcinoma in rats and is implicated as a cofactor in esophageal or hepatic carcinoma. Previous studies concluded that FB1 repressed cyclin-dependent kinase 2 (CDK2) activity but induced CDK inhibitors p21(Waf1/Cip1), p27(Kip1), and p57(Kip2) in monkey kidney cells (CV-1). In contrast, CV-1 cells transformed by simian virus 40 are resistant to the antiproliferative or apoptotic effects of FB1. Consequently, FB1 treatment of CV-1 cells leads to cell cycle arrest and apoptosis. In this study, we demonstrate that FB1 transcriptionally activates the p21 promoter. Functional analysis of the p21 promoter by reporter gene assays mapped the FB1-responsive region to -124 to -47. DNase I footprinting analysis revealed two protected motifs that span the FB1-responsive region, -124 to -101 (footprint II) and -89 to -67 (footprint III). Further studies demonstrated that DNA sequences from -124 to -101 were sufficient for FB1 stimulation. DNA sequences from -124 to -101 contain two Sp1 binding sites, and gel shift assays provided evidence that nuclear factors specifically bind to this region. Disruption of the two Sp1 binding sites abrogated the binding of nuclear proteins and prevented activation by FB1. Taken together, these results suggest that Sp1 or Sp1-related proteins mediate FB1-induced activation of the p21 promoter.

X-ray Absorption Spectroscopy of Tricarbonatodioxouranate(V), [UO(2)(CO(3))(3)](5)(-), in Aqueous Solution

Actinyl ions (AnO(2)(+) and AnO(2)(2+)) are strongly complexed by CO(3)(2)(-) in aqueous solution, and tricarbonato complexes of UO(2)(2+) and NpO(2)(+), in particular, have been widely studied. Cyclic voltammetry shows that, whereas the Np(V)/Np(VI) couple is reversible in aqueous CO(3)(2)(-) solution, the analogous U couple is irreversible, suggesting significant conformational change on one-electron reduction of [UO(2)(CO(3))(3)](4)(-). EXAFS spectroscopy has been used to define the coordination geometry of the reduced species and shows that both axial and equatorial U-O distances increase on reduction, from 1.80 to 1.90 Å and from 2.43 to 2.50 Å, respectively. The basic geometry of the U complex is apparently unchanged by reduction so any conformational change which does occur must be subtle.

PRN Pool in a mental health center setting

Midtown Mental Health Center/Memphis and Shelby County Emergency Mental Health Services, Inc., is a community mental health center located in the downtown area of Memphis/Shelby County, Tennessee, a large urban metropolitan area. The center established a temporary pool of employees for each center program to provide coverage of critical positions. The PRN Pool is designed to minimize disruptions to client services during employee absences. The article outlines the benefits to the center, the employees, and the consumer.

Dilemmas in the ethics of health-care research

Evidence-based practice is now widely accepted as the most appropriate basis of patient care. Humans should only be used as research subjects with their full consent and in their best interests. Ethics committees play a pivotal role in maintaining the balance between scientific advances and ethical research.

Carbonate induced dissolution of uranium containing precipitates under cement leachate conditions

The effects of carbonate on uranium (VI) solubility under aerobic and cementitious conditions have been investigated. The information is of relevance to low level nuclear waste disposal. Aqueous NaOH, KOH, Ca(OH)2 and a cement leachate solution were added to uranyl nitrate solution. Afterwards, increasing amounts of ammonium carbonate were added to re-dissolve the precipitates. The precipitates were characterised by means of X-ray powder diffraction (XRPD) measurements and modelling studies. The model calculations were performed using the MINTEQA2 speciation code, with an expanded database incorporating uranium stability constants taken from the HATCHES database. The measured and predicted amounts of CO3(2-) needed to dissolve the precipitates were compared. The knowledge gained from the 'pure' systems was used to rationalise the precipitation and re-dissolution behaviour observed in the leachate system. The lack of uranium solubility at low carbonate levels brought into question literature formation constants for UO2(OH)3- and UO2(OH)4(2-). An approximate log K value of 26.8 for K2U2O7 formation was estimated from the KOH results at pH 12. Generally, uranium solubilities are expected to be insignificant at low level nuclear waste sites because anaerobic conditions should persist. However, this study has demonstrated that solubility in leachate could rise at high pH and high carbonate levels, if aerobic conditions were to develop. Soluble U(VI) species would be formed. The novel part of the study has been to reproduce the effects and to correlate enhanced solubilities with model predictions. Consequently, the study has re-emphasised the need for appropriate environmental monitoring of such sites.

Use of ultrasonography in the patient with acute renal trauma

The purpose of this study was to assess the use of emergent ultrasonographic examination in acute traumatic renal injuries. Over a 3 year period, prospective data of all patients who had an emergency ultrasonogram were recorded. Thirty-two patients with 37 renal injuries were studied retrospectively to identify in how many patients the sonogram detected free fluid or a renal parenchymal abnormality. Free fluid in the abdomen was identified in 19 of 32 patients (59%). However, 12 of these 19 patients had concomitant injury, such as splenic rupture requiring splenectomy, severe liver lacerations, or bowel lacerations requiring repair, that were possible causes of the free fluid. Eliminating these patients, only seven of 20 patients with isolated renal injuries had free fluid in the abdomen (35%), whereas 13 of 20 patients (65%) had no evidence of free fluid. All seven patients with free fluid had moderate or severe renal injuries. Renal parenchymal abnormalities were identified on ultrasonograms in eight of 37 (22%) of injured kidneys. The abnormalities were detected more commonly in cases of severe injury (60%). In conclusion, acute injuries of the kidney from blunt abdominal trauma often are associated with significant splenic, hepatic, or bowel trauma. Isolated renal injuries frequently occur without the presence of free fluid in the abdomen. Furthermore, the ultrasonogram of the kidney often is normal with acute renal injuries, but it is more likely to be abnormal with severe (grade II or greater) renal injuries. Sonography may be used in the triage of patients with blunt abdominal trauma and possible renal injury. However, a negative ultrasonogram does not exclude renal injury, and, depending on clinical and laboratory findings, other imaging procedures such as computed tomography should be performed.

Accurate memory for colour but not pattern contrast in chicks

The visual displays of animals and plants often look dramatic and colourful to us, but what information do they convey to their intended, non-human, audience [1] [2]? One possibility is that stimulus values are judged accurately - so, for example, a female might choose a suitor if he displays a specific colour [3]. Alternatively, as for human advertising, displays may attract attention without giving information, perhaps by exploiting innate preferences for bright colours or symmetry [2] [4] [5]. To address this issue experimentally, we investigated chicks' memories of visual patterns. Food was placed in patterned paper containers which, like seed pods or insect prey, must be manipulated to extract food and their patterns learnt. To establish what was learnt, birds were tested on familiar stimuli and on alternative stimuli of differing colour or contrast. For colour, birds selected the trained stimulus; for contrast, they preferred high contrast patterns over the familiar. These differing responses to colour and contrast show how separate components of display patterns could serve different roles, with colour being judged accurately whereas pattern contrast attracts attention.