H RAS mutations in haematologically normal individuals

INTRODUCTION

Point mutations in N, K and H RAS have been found in adverse haematological malignancies. The background frequency of RAS mutations in the normal population has yet to be determined. Here we report the results of a screen for RAS mutations from normal individuals.

MATERIALS AND METHODS

DNA from peripheral blood or bone marrow from 115 haematologically normal individuals was screened for point mutations in N, K and H RAS, at amino acid positions 12, 13 and 61. The screening was done using polymerase chain reaction and oligonucleotide hybridisation and candidate mutations were subsequently confirmed by cloning and sequencing.

RESULTS AND CONCLUSION

Point mutations were identified in DNA from two of the 115 individuals. Both mutations resulted in an amino acid substitution at position 12 in H RAS. Both individuals with detectable H RAS mutations remain haematologically normal.

Cortisol-binding globulin is important in the interpretation of dynamic tests of the hypothalamic--pituitary--adrenal axis

OBJECTIVE

Assessment of the hypothalamic--pituitary--adrenal (HPA) axis relies on the interpretation of serum (total) cortisol in response to dynamic tests of the HPA axis. Most cortisol is bound to cortisol-binding globulin (CBG) and serum total cortisol levels are significantly affected by variation in CBG. We hypothesised that CBG variation significantly affects interpretation of dynamic tests of the HPA axis.

DESIGN

We investigated the effect of CBG variation on the outcome of the 250 microg short Synacthen test (SST) in 30 healthy adults.

METHODS

Blood was sampled at time -30, 0 (at which point Synacthen was given) and +30 min. CBG and total cortisol were measured at each time-point. Integrity of the HPA axis was confirmed by measurement of urine cortisol.

RESULTS

We found that CBG varied significantly within individuals, falling from 51+/-3.4 to 43 +/-3.2 microg/ml (P<0.0001) on changing from standing to lying. Total cortisol levels strongly correlated with CBG (r=0.88, P<0.0001). Thirteen subjects had a +30 min total cortisol <550 nmol/l. In these subjects, the CBG levels at each time-point were significantly lower compared with subjects who had a +30 min total cortisol of >550 nmol/l (P<0.05). To correct for variation in CBG we calculated the total cortisol:CBG ratio and found no significant difference in the +30 min ratio between these two groups.

CONCLUSION

CBG varies significantly within and between individuals. This is accompanied by changes in serum total cortisol large enough to affect the outcome of an SST and, by implication, other tests of the HPA axis.

A method for measuring particle number emissions from vehicles driving on the road

Earlier research has demonstrated that the conditions of dilution of engine exhaust gases profoundly influence the size distribution and total number of particles emitted. Since real world dilution conditions are variable and therefore difficult to simulate, this research has sought to develop and validate a method for measuring particle number emissions from vehicles driving past on a road. This has been achieved successfully using carbon dioxide as a tracer of exhaust gas dilution. By subsequent adjustment of data to a constant dilution factor, it is possible to compare emissions from different vehicles using different technologies and fuels based upon real world emission data. Whilst further optimisation of the technique, especially in terms of matching the instrument response times is desirable, the measurements offer useful insights into emissions from gasoline and diesel vehicles, and the substantial proportion of particles emitted in the 3-7 nanometre size range.

Shortfall in mental health service utilisation

BACKGROUND

Treatment coverage for mental disorders is poor in most developed countries.

AIMS

To explore some reasons for the poor treatment coverage for mental disorders in developed countries.

METHOD

Data were taken from Australian national surveys and from the World Health Report.

RESULTS

Only one-third of people with a mental disorder consulted. Probability of consulting varied by diagnosis: 90% for schizophrenia, which is accounted for by external factors; 60% for depression; and 15% for substance use and personality disorders. The probability of consulting varied by gender, age, marital status and disability, from 73% among women aged 25-54 years, disabled and once married to 9% among males without these risk factors. Those who did not consult but were disabled or comorbid said that they "preferred to manage themselves". Data from five countries showed no evidence that overall health expenditure, out-of-pocket cost or responsiveness of the health system affected the overall consulting rates.

CONCLUSIONS

Societal, attitudinal and diagnostic variables account for the variation. Funding does not. Public education about the recognition and treatment of mental disorders and the provision of effective treatment by providers might remedy the shortfall.

Human anti-idiotypic antibodies can be good immunogens as they target FC receptors on antigen-presenting cells allowing efficient stimulation of both helper and cytotoxic T-cell responses

Anti-idiotypic antibodies that mimic tumour-associated antigens can stimulate anti-tumour T-cell responses. In this article, we have studied the role of Fc in the presentation of T-cell epitopes by 2 anti-idiotypic antibodies, 105AD7 and 708. The human monoclonal antibody 105AD7, which mimics CD55, stimulated strong in vitro T-cell proliferation, gammaIFN secretion and redirected cytotoxicity in unprimed T cells from healthy donors. However, removal of the Fc region of the anti-idiotype reduced the sensitivity of the assay 1,000-fold, as did inhibiting Fc uptake of the anti-idiotype by an excess of human IgG. The mouse anti-idiotype 708, which mimics CEA, failed to stimulate in vitro T-cell responses on unprimed T cells from healthy donors. However, when a human IgG1 Fc region replaced its mouse Fc region, the anti-idiotype induced T-cell proliferation, gammaIFN secretion and redirected cytotoxicity in lymphocytes from unimmunised donors. Human anti-idiotypes are therefore good immunogens since they target Fc receptors on antigen-presenting cells, allowing efficient stimulation of both helper and cytotoxic T-cell responses. The immunogenicity of other anti-idiotypes may therefore be enhanced by human Fc targeting of antigen-presenting cells.

Identification of residues in the carboxy-terminal domain of Clostridium perfringens alpha-toxin (phospholipase C) which are required for its biological activities

A panel of random mutants within the DNA encoding the carboxy-terminal domain of Clostridium perfringens alpha-toxin was constructed. Three mutants were identified which encoded alpha-toxin variants (Lys330Glu, Asp305Gly, and Asp293Ser) with reduced hemolytic activity. These variants also had diminished phospholipase C activity toward aggregated egg yolk phospholipid and reduced cytotoxic and myotoxic activities. Asp305Gly showed a significantly increased enzymatic activity toward the monodisperse substrate rhoNPPC, whereas Asp293Ser displayed a reduced activity toward this phospholipid analogue. In addition, Asp293Ser showed an increased dependence on calcium for enzymatic activity toward aggregated phospholipid and appeared calcium-depleted in PAGE band-shift assays. In contrast, neither Lys330Glu nor Asp305Gly showed altered dependence on calcium for enzymatic activity toward aggregated phospholipid. Asp305 is located in the interface between the amino- and carboxy-terminal domains, whereas Asp293 and Lys330 are surface exposed residues which may play a role in the recognition of membrane phospholipids.

Pancreatic elastase activates pulmonary nuclear factor kappa B and inhibitory kappa B, mimicking pancreatitis-associated adult respiratory distress syndrome

BACKGROUND

Select pancreatic enzymes, primarily elastase, precipitate pulmonary injury similar to pancreatitis-associated adult respiratory distress syndrome and stimulate leukocyte cytokine production in vitro via nuclear factor kappa B (NF-kappaB) activation. This study explores the effect of systemic pancreatic enzymes on pulmonary NF-kappaB and inhibitory kappa B (IkappaB) proteins and their role in enzyme-induced pulmonary injury.

METHODS

Mice received pancreatic elastase, amylase, lipase, or trypsin intraperitoneally. Bronchoalveolar lavage IkappaBalpha/IkappaBbeta proteins were measured by immunoblot. Pulmonary NF-kappaB activation, tumor necrosis factor (TNF) gene expression, and neutrophil infiltration (myeloperoxidase) were determined and myeloperoxidase experiments repeated in p55 TNF receptor-deficient (TNF KO) animals. Additional animals received pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-kappaB activation, and TNF protein and pulmonary microvascular permeability were measured after elastase administration.

RESULTS

Pancreatic elastase induced pulmonary IkappaBalpha/IkappaBbeta degradation (30 minutes), NF-kappaB activation (60 minutes), and TNF gene expression (60 minutes) with subsequent neutrophilic inflammation (4 hours) and microvascular leakage (24 hours), whereas amylase, lipase, and trypsin did not. Furthermore, lung injury was markedly reduced in TNF KO animals and PDTC significantly attenuated TNF production and pulmonary microvascular leakage.

CONCLUSIONS

Pancreatic elastase induces cytokine-mediated lung injury and this pathway involves the NF-kappaB second messenger system, further supporting elastase as a factor linking pancreatic inflammation to systemic illness during severe acute pancreatitis.

Liposome-mediated, nonviral gene transfer induces a systemic inflammatory response which can exacerbate pre-existing inflammation

Cationic liposome and plasmid-mediated gene transfer has emerged as a novel technique for the targeted delivery of protein-based therapies in acute inflammatory diseases. However, concerns have arisen that cationic liposomes and plasmid DNA have inherent proinflammatory properties which could exacerbate pre-existing inflammatory processes. In healthy mice, intraperitoneal administration of cationic liposomes (200 nmol) complexed to plasmid DNA (100 microg) induced a proinflammatory response characterized by the induction of tumor necrosis factor alpha and interleukin-1beta mRNA expression. The plasma concentrations of the hepatic acute phase proteins interleukin-6, amyloid A, amyloid P, and seromucoid were also increased (P<0.05), and this response was seen in endotoxin-resistant (C3H/HeJ) mice. The inflammatory response associated with gene transfer increased the mortality and severity of experimentally induced sterile inflammation (pancreatitis). We conclude that systemic administration of cationic liposomes and plasmid DNA is associated with induction of the innate immune response which may exacerbate pre-existing inflammatory processes.

Specific pancreatic enzymes activate macrophages to produce tumor necrosis factor-alpha: role of nuclear factor kappa B and inhibitory kappa B proteins

The triggering events by which mononuclear cells throughout the body are induced to produce large amounts of cytokines during acute pancreatitis are unclear. However, recent work in our laboratory demonstrated that three specific pancreatic enzymes (elastase, carboxypeptidase A, and lipase) induced dramatic tumor necrosis factor-alpha (TNF-alpha) protein production from macrophages, whereas all others could not. This series of experiments was designed to examine the second messenger system by which this occurs. The rat macrophage cell line NR8383 was incubated for 3 hours with elastase, carboxypeptidase A, lipase, trypsin, or lipopolysaccharide (positive control). Activation of nuclear factor kappa B (NF-kappa B) was demonstrated by electrophoretic mobility shift assay, presence of inhibitory kappa B alpha and beta (I kappa B-alpha and I kappa B-beta) by Western blot analysis, and TNF-alpha protein production by enzyme-linked immunosorbent assay. Elastase, carboxypeptidase A, and lipase induced degradation of I kappa B-beta (but not I kappa B-alpha), activation of NF-kappa B, and production of TNF-alpha protein, whereas inhibition of I kappa B with pyrrolidine dithiocarbamate attenuated this response. Trypsin was unable to elicit any of these responses. Macrophages can be induced by specific activated pancreatic enzymes-elastase, carboxypeptidase A, and lipase-to produce TNF-alpha. This process is dependent on I kappa B-beta degradation and NF- kappa B activation, suggesting that these enzymes trigger this second messenger system through specific membrane-bound receptors.

A study to evaluate serum and urinary hormone levels following short and long term administration of two regimens of progesterone cream in postmenopausal women

OBJECTIVE

To determine the pharmacokinetics of a progesterone cream following short and long term dermal administration.

DESIGN

Single-centre, randomised, multiple-dose, open-label study.

SETTING

Reproductive Medicine Trust, London.

POPULATION

Twenty-four healthy postmenopausal women aged between 40 and 65 years were recruited through an advertisement in a local newspaper.

METHODS

The women were randomly allocated to progesterone cream 40 mg daily or 20 mg, twice daily, for 42 days.

MAIN OUTCOME MEASURES

The concentration of progesterone in the serum was measured on days 1 and 42 before the morning dose, and at 2, 4, 6, 12 and 24 hours after the morning dose. Serum follicle stimulating hormone, oestradiol, testosterone and urinary pregnanediol-3-glucuronide were also measured on days 1 and 42.

RESULTS

Three subjects dropped out before using the cream and two more dropped out after the first treatment leaving a reportable sample of 19 women. There was a rise in the mean progesterone concentration at each sampling time between days 1 and 42. There was evidence of a rise in pregnanediol-3-glucuronide over the course of the study. There was no change in follicle stimulating hormone, oestradiol or testosterone. There was no difference between the two regimens.

CONCLUSIONS

Transdermal progesterone (40 mg) per day for 42 days causes a small increase in serum progesterone concentration, although there is wide variation. Whether such levels are of clinical benefit remains to be seen.

Rehabilitation of executive functioning: an experimental-clinical validation of goal management training

Two studies assessed the effects of a training procedure (Goal Management Training, GMT), derived from Duncan's theory of goal neglect, on disorganized behavior following TBI. In Study 1, patients with traumatic brain injury (TBI) were randomly assigned to brief trials of GMT or motor skills training. GMT, but not motor skills training, was associated with significant gains on everyday paper-and-pencil tasks designed to mimic tasks that are problematic for patients with goal neglect. In Study 2, GMT was applied in a postencephalitic patient seeking to improve her meal-preparation abilities. Both naturalistic observation and self-report measures revealed improved meal preparation performance following GMT. These studies provide both experimental and clinical support for the efficacy of GMT toward the treatment of executive functioning deficits that compromise independence in patients with brain damage.

Intervening with everyday memory problems in dementia of Alzheimer type: an errorless learning approach

Dementia of Alzheimer Type (DAT) is increasingly detected at an earlier stage of the disorder, when interventions to assist with everyday memory difficulties might be most valuable. Some learning is possible in DAT and a number of factors have been identified which may facilitate performance, although applications to everyday memory problems have been limited. The concept of errorless learning has not previously been directly examined in relation to DAT, but might provide a useful additional strategy. In the present study, 6 participants with early stage DAT (MMSE scores 21 - 26) received individually tailored interventions, based on errorless learning principles and targeted at a specific everyday memory problem. Five of the participants showed significant improvement on the target measures, and maintained this improvement up to 6 months later. The results suggest that it is feasible to intervene with everyday memory problems in the early stages

Harvesting and implanting allograft bone

Allograft bone (i.e., bone that is obtained from a donor) implantation is used for bone replacement and for reconstructing serious bone defects during total joint revision surgery. It is also used for bone replacement after large excisions of bone tumors. An extensive variety of laboratory tests must be completed, appropriate storage facilities for allograft bone have to be available, and protocols must be developed before a facility can set up a bone bank. Many ethical issues and nursing responsibilities need to be considered before the decision is made to use allograft bone.

The midnight to morning urinary cortisol increment is an accurate, noninvasive method for assessment of the hypothalamic-pituitary-adrenal axis

The optimal method for assessing the hypothalamic-pituitary-adrenal axis (HPA) remains controversial. The insulin tolerance test (ITT) is considered the gold standard, but is invasive and potentially dangerous. The short Synacthen test (SST) is the most commonly used alternative, but its concordance with the ITT is poor. Using sleep as a reliable stimulus to ACTH release, we proposed that the increment in urinary cortisol levels between midnight and waking could provide a noninvasive, physiological means for the assessment of the HPA axis. Double voided urine samples were collected at home at midnight and waking in 40 patients with pituitary disease and 40 controls. Cortisol and creatinine levels were measured, and the cortisol/creatinine (Cort/Cr) ratio was calculated. The Cort/Cr increment was defined as the morning Cort/Cr ratio minus the midnight Cort/Cr ratio. The Cort/Cr increment of the patients was compared to the results of their ITT or SST. Using the results from the 40 controls, a normal Cort/Cr increment was defined as greater then 9. The positive predictive value of a Cort/Cr increment for the diagnosis of HPA insufficiency was 95%. These findings suggest that the midnight to morning Cort/Cr increment is a reliable, noninvasive alternative to the ITT/SST for assessment of the HPA.

Circulating stress hormone and insulin concentrations in acute coronary syndromes: identification of insulin resistance on admission

We re-examined, in the context of modern practice, plasma insulin and stress hormone concentrations in patients admitted to hospital with acute coronary syndromes. Venous blood sampling was carried out prior to anti-thrombotic therapy in 148 patients with myocardial infarction (MI); 76 patients with unstable angina (UA) pectoris were also studied, together with 27 patients with non-cardiac chest pain (NCP). There were significant progressive increases in the concentrations of catecholamines, cortisol, glucose and insulin from NCP to UA to MI patients. Hyperglycaemia (glucose >8 mmol/l) was present in over 50% of MI patients. The plasma cortisol and insulin levels were both significantly positively correlated with the glucose concentration on admission. Only the cortisol concentration was correlated with peak cardiac enzyme levels. The glucose and insulin concentrations on admission in 141 MI and UA patients were related to insulin resistance, as judged from subsequent insulin and glucose concentrations measured while fasting and during a glucose tolerance test. The product of admission insulinxglucose (divided by 25; the admission insulin-resistance index, or AIRI) was significantly correlated with indices of insulin resistance, and was significantly higher (approximately double) in the MI group (7. 81+/-0.76) and the UA group (6.88+/-1.19) than in the control NCP group (3.59+/-0.06; Kuskul-Wallis: P=0.0001), implying that the insulin levels in the first two groups were approximately twice as high as is appropriate for the glucose levels. The ethnic origin of 20% of the patients was the Indian subcontinent; admission insulin and glucose levels in this subgroup were higher than in the non-Asians across all the groups with chest pain. Cortisol was the only stress hormone that was raised in proportion to the size of the infarct, and is a likely partial cause of the elevation in blood glucose. The high insulin levels were related to the prevalence of insulin resistance, and this was particularly important in the Asian subgroup presenting with MI and UA. Thus it appears feasible to identify acute coronary syndrome patients who are insulin-resistant at a time (on admission) when alternative early therapeutic strategies can be instituted.