'Hello, my name is Gabriel, I am the house officer, may I examine you?' or the Objective Santa Christmas Examination (OSCE)

OBJECTIVE

To design a clinical examination of high content validity suitable for use as a formative assessment tool with pre-registration house officers (PRHO'S) towards the end of their first house officer post.

DESIGN

A multicentre collaboration between four UK medical schools who offer undergraduate curricula which are problem-based, systems-based, patient-orientated, student-centred, jargon-laden and utterly staff-bewildering.

MAIN OUTCOME

An objective structured clinical examination (OSCE) which is suitable for use with graduates of UK medical schools. It assesses the knowledge, skills and attitudes essential for future careers in a hierarchical system where protecting the senior staff from all forms of irritation is paramount.

RESULTS

PRHO'S who excel in this examination get better references.

CONCLUSION

The OSCE format can be used to provide 'real-life' scenarios appropriate to the season.

Observations on centrifugation: application to centrifuge development

This report outlines the background to the development of an automated, serial, discrete centrifuge, reporting on the criteria considered essential in such an instrument. We established the criteria by examining the detailed logistics of centrifuge operation in a hospital laboratory. The mean sample load per run, using six centrifuges, was 13.6 samples, and the user-selectable cycle time ranged from 00:01:10 to 00:12:33 (hours:minutes:seconds) with a fixed g value of 1050. During the laboratory working window, (0900-1700), only 50% of the centrifuge capacity was utilized and more than one-third of the sample workload was delayed for >5 min because the centrifuges were not emptied promptly. In addition, 35% of the sample workload was centrifuged for less than the time prescribed in the operational specifications. Based on these findings, we designed a new continuous, serial centrifuge to overcome some of the deficiencies noted in the logistics study. The centrifuge operates continuously, nominally treating 150 samples/h, with a cycle time of 5 min at 1,000 g. The cycle time and g value are variable between limits, and their selection governs the throughput rate. Each sample is centrifuged separately in individual rotors mounted in a sturdy carousel with a periphery that traverses a load/unload station. There is no sample delay because of operator absence, and the capacity is fully utilized. The centrifuge can operate in a stand-alone capacity or has the capability of being integrated into a sample preparation system or as a direct front end for high-throughput analyzers.

Responses of single taste fibers and whole chorda tympani and glossopharyngeal nerve in the domestic pig, Sus scrofa

Whole nerve, as well as single fiber, responses in the chorda tympani proper (CT) and glossopharyngeal (NG) nerves of 1- to 7-week-old pigs were recorded during taste stimulation. In the CT acids and in the NG bitter compounds gave the largest responses. Both nerves exhibited large responses to monosodium glutamate (MSG), MSG with guanosine 5'-monophosphate (GMP) and MSG with inositine 5'-monophosphate (IMP) as well as to glycine, xylitol, sucrose, fructose and glucose. Alitame, aspartame, betaine, neohesperedin dihydrochalcone (NHDHC), super-aspartame, saccharin and thaumatin elicited no or little response. Hierarchical cluster analysis of 49 CT fibers separated four major clusters. The M cluster, comprising 28.5% of all fibers, is characterized by strong responses to MSG, KCl, LiCl and NaCl. The responses to NaCl and LiCl were unaffected by amiloride. The H cluster (24.5%) includes units responding principally to acids. The Q cluster (18.5%) responds to quinine hydrochloride (QHCl), sucrose octaacetate (SOA) and salts with amiloride. The S cluster (28.5%) exhibits strong responses to xylitol, glycine and the carbohydrates as well as to MSG alone and to MSG with GMP or IMP. In 31 NG fibers, hierarchical cluster analysis revealed four clusters: the M cluster (10%), responding to MSG and MSG with GMP or IMP; the H cluster (13%), responding to acids; the Q cluster (29%), responding strongly to QHCl, SOA and tilmicosinR; and the S cluster (48%), responding best to xylitol, carbohydrates and glycine but also to the umami compounds. Multidimensional scaling analysis across fiber responses to all stimuli showed the best separation between compounds with different taste qualities when information from both nerves was utilized.

Cortical auditory signal processing in poor readers

Magnetoencephalographic responses recorded from auditory cortex evoked by brief and rapidly successive stimuli differed between adults with poor vs. good reading abilities in four important ways. First, the response amplitude evoked by short-duration acoustic stimuli was stronger in the post-stimulus time range of 150-200 ms in poor readers than in normal readers. Second, response amplitude to rapidly successive and brief stimuli that were identical or that differed significantly in frequency were substantially weaker in poor readers compared with controls, for interstimulus intervals of 100 or 200 ms, but not for an interstimulus interval of 500 ms. Third, this neurological deficit closely paralleled subjects' ability to distinguish between and to reconstruct the order of presentation of those stimulus sequences. Fourth, the average distributed response coherence evoked by rapidly successive stimuli was significantly weaker in the beta- and gamma-band frequency ranges (20-60 Hz) in poor readers, compared with controls. These results provide direct electrophysiological evidence supporting the hypothesis that reading disabilities are correlated with the abnormal neural representation of brief and rapidly successive sensory inputs, manifested in this study at the entry level of the cortical auditory/aural speech representational system(s).

Cutting edge: recruitment of the CD19/CD21 coreceptor to B cell antigen receptor is required for antigen-mediated expression of Bcl-2 by resting and cycling hen egg lysozyme transgenic B cells

Recruitment of the CD19/CD21 coreceptor is thought to lower the threshold for effective signaling through the B cell Ag receptor. We provide evidence supporting a second role for coreceptor recruitment, and that is to enhance the survival/proliferative potential of the responding B cells. We show that B cell Ag receptor signaling in the absence of coreceptor recruitment induces cellular accumulation of the anti-apoptotic protein Bcl-xL, whereas CD19-mediated signals are required for Bcl-2 accumulation. The expression of both anti-apoptotic proteins correlates with the enhanced responsiveness of both resting and cycling B cells to growth-promoting signals delivered through CD40. These results provide further evidence for the necessity of coreceptor recruitment during Ag-dependent B cell activation and indicate that Ags derived from inflammatory sites function as better thymus-dependent Ags than their counterparts not coated with complement fragments.

Carboplatin and paclitaxel, alone and in combination: dose escalation, measurement of renal function, and role of the p53 tumor suppressor gene

In this pharmacokinetic and dose-escalation study of the carboplatin/paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) combination, patients were randomly assigned to receive paclitaxel either as a 1-hour or a 3-hour infusion. The 1-hour infusion was feasible, with maximum tolerated doses similar to those previously reported for a 3-hour infusion. Using patients' age, height, plasma creatinine, and plasma creatine kinase provided an improved estimate of the glomerular filtration rate compared with the more traditional creatinine-based formulas according to population analysis of data derived from glomerular filtration rate estimates performed by an isotope method. Studies of the p53 gene sequence of ovarian tumors at diagnosis suggest that p53 mutations are a potent predictor of response to subsequent treatment with carboplatin.

[Diagnosis of an intramyocardial hematoma via MRI after a traumatic myocardial infarct]

Traumatic cardiac lesions occur in about 30% of all traumatized patients, in most cases they are due to traffic accidents. We report a patient who suffered from a traumatic anterior wall infarction following a ski accident. Consecutively, an extended intramyocardial hemorrhage occurred. A left ventricular pseudoaneurysm was considered first by echocardiography. Using MRI, an intramyocaridal hemorrhage could be diagnosed because of a thin myocardial border surrounding the hematoma. Consecutively, the patient underwent CABG surgery as well as a resection of the intramyocardial hematoma. This diagnosis could be manifested surgically and histologically.

Successful treatment of cerebral toxoplasmosis in a marrow transplant recipient: contribution of a PCR test in diagnosis and early detection

We report successful treatment of cerebral toxoplasmosis in an unrelated donor marrow transplant recipient. The clinical diagnosis was confirmed by polymerase chain reaction (PCR) amplification for T. gondii-DNA performed both on cerebrospinal fluid and blood leukocytes. Retrospective testing of stored blood samples demonstrated positive leukocyte PCR signal detected up to 52 days prior to onset of clinical symptoms. This case highlights the value of PCR in the diagnosis and early detection of cerebral toxoplasmosis.

TTC4, a novel human gene containing the tetratricopeptide repeat and mapping to the region of chromosome 1p31 that is frequently deleted in sporadic breast cancer

The 1p31 region shows loss of heterozygosity in up to 50% of human breast cancers, indicating the presence of a tumor suppressor gene in this location. We have mapped six novel ESTs to a 15-Mb contig of yeast artificial chromosomes spanning the critical region of 1p31. One of these ESTs was localized within the contig to the region most commonly undergoing loss of heterozygosity in breast cancer. The corresponding gene sequence for this EST was established by cDNA cloning and RACE procedures. This gene is 2 kb long and contains a tetratricopeptide repeat motif and a coiled-coil domain. This family of genes has been implicated in a wide variety of functions, including tumorigenesis. This is the fourth member of the human gene family, and so we have named this gene TTC4. Northern blot analysis demonstrates a ubiquitous pattern of gene expression that includes breast tissue. A preliminary screen of human breast cancer cell lines shows that TTC4 is expressed in all cases, but SSCP analysis of the coding region of this gene following RT-PCR failed to reveal any mutations. Clearly, because of its map location, a more extensive analysis is warranted to establish whether subtle mutations are present in breast cancers.

Diurnal variation in saliva estriol level during pregnancy: a pilot study

OBJECTIVE

The object of the study was to characterize daily values and patterns of salivary estriol levels during normal pregnancy at mid to late gestation.

STUDY DESIGN

We measured salivary estriol levels in a clinical research center setting with an established enzyme-linked immunosorbent assay. Fourteen pregnant women (24-36 weeks' gestation) submitted unstimulated saliva samples hourly from 10:00 am until 10:00 pm and at midnight and 2:00, 4:00, 6:00, and 8:00 am.

RESULTS

Each subject demonstrated greater salivary estriol levels at night (10:00 pm-6:00 am) than in the daytime (8:00 am-9:00 pm, P <.001). Salivary estriol levels consistently increased at 10:00 pm, peaked at 4:00 am, and returned to daytime levels between 6:00 and 7:00 am. Salivary estriol concentrations were stable during daylight hours.

CONCLUSIONS

(1) There was a dramatic diurnal variation in salivary estriol levels (nadir during daylight with nighttime apogee). (2) Diurnal patterns and salivary estriol levels were consistent in each of 14 subjects evaluated in the latter half of pregnancy. Samples for baseline measurements of salivary estriol level should be obtained during daylight hours (8:00 am-8:00 pm).

Behavioral and single chorda tympani taste fiber responses in the common marmoset, Callithrix jacchus jacchus

Gustatory responses of the common marmoset were studied using single fiber recordings from chorda tympani (CT) nerve and two bottle preference (TBP) tests. Hierarchical cluster analysis of 43 fibers' response profiles revealed 3 major clusters of fibers characterized by predominant sensitivity to sweeteners (S cluster), bitter compounds (Q cluster) or acids (H cluster). NaCl as well as LiCl did not stimulate CT taste fibers. The TBP tests showed relationship between a compound's ability to stimulate the taste fibers and the animals' consumption. Activity in the S cluster was associated with preference, while the activity in the Q cluster was associated with rejection. Marmosets neither preferred nor rejected sweeteners which did not stimulate any CT fibers.

Cytokine transgene expression and promoter usage in primary CD34+ cells using particle-mediated gene delivery

Induction or short-term transgenic expression of specific cytokines, growth factors, or other candidate therapeutic genes in hematopoietic progenitor or stem cells is potentially applicable to gene therapy for cancer. In this study, we explored the application of a gene gun technique, as an alternative to viral vectors, for ex vivo gene transfer into and transient gene expression in highly enriched CD34+ cells derived from human umbilical cord blood. Twenty-four hours posttransfection, 32.6 to 1500 pg/l x 10(6) CD34+ cells of transient gene expression was routinely obtained for specific cytokine and reporter genes. Transgene expression at the single-cell level was revealed by X-Gal staining of lacZ cDNA-transfected CD34+ cells. Expression of four candidate therapeutic genes, namely human granulocyte-macrophage colony-stimulating factor, tumor necrosis factor alpha, interleukin 2, and interferon gamma, was detectable for 4 to 7 days in CD34+ cells. A human elongation factor 1alpha promoter/intron 1 transcription unit was identified as a strong cellular promoter for CD34+ cells, exhibiting strength similar to that of the commonly employed cytomegalovirus immediate-early promoter. These results suggest that the nonviral, gene gun technique offers an efficient alternative approach for transient transgenic studies of hematopoietic cells and may provide new possibilities for certain cancer gene therapy strategies using CD34+ cells.

[Flow quantification of intracardiac shunt volumes using MR phase contrast technique in the breath holding phase]

PURPOSE

Comparison of a breath-hold, velocity-encoded, phase-difference magnetic resonance (MR) sequence for intracardiac shunt flow measurement with the invasive shunt size determination by oximetry.

PATIENTS AND METHODS

10 patients with different cardiac shunts (6 ASD/3 VSD/1 PDA) and four healthy individuals were investigated using a 1.5 Tesla Siemens Vision system. For flow measurements a breath-hold, velocity-encoded, phase-difference magnetic resonance (MR) sequence was used ('through plane', FLASH 2D-sequence, TR/TE 110/5 ms, 'velocity encoding' 250 cm/s). Mean flow (ml/R-R interval) in the ascending aorta, the pulmonary trunk, and the right and left pulmonary arteries was determined. The ratio of the mean flow in the pulmonary circulation (Qp: sum of the mean flows in the right and left pulmonary arteries) and the systemic circulation (Qs: mean flow in the proximal aorta) was compared with the Qp/Qs ratios determined by the invasive oxymetric technique. Oximetry was performed within 24 hours after MR imaging.

RESULTS

In the 4 healthy individuals MR flow measurement yielded a Qp/Qs ratio of 0.96 +/- 0.15. In the 10 patients with the various shunt defects, the non-invasive shunt determination by MR gave a Qp/Qs ratio of 2.09 +/- 0.67. The percentage of the calculated shunt sizes was 47.05 +/- 17.45%. In the comparison with the results determined by the invasive oxymetric technique, the MR data showed a strong correlation of r = 0.87.

CONCLUSIONS

Breath-hold, velocity-encoded, phase-difference MR-technique enables a reliable quantification of cardiac shunts within a short acquisition time.

Choosing options for ultrasound screening in pregnancy and comparing cost effectiveness: a decision analysis approach

OBJECTIVE

To compare the cost effectiveness of different programmes of routine antenatal ultrasound screening to detect four key fetal anomalies: serious cardiac anomalies, spina bifida, Down's syndrome and lethal anomalies, using existing evidence.

DESIGN

Decision analysis was used based on the best data currently available, including expert opinion from the Royal College of Obstetricians and Gynaecologists, Working Party and secondary data from the literature, to predict the likely outcomes in terms of malformations detected by each screening programme.

SETTING

Results applicable in clinics, hospitals or GP practices delivering antenatal screening.

MAIN OUTCOME MEASURE

The number of cases with a 'target' malformation correctly detected antenatally.

RESULTS

There was substantial overlap between the cost ranges of each screening programme demonstrating considerable uncertainty about the relative economic efficiency of alternative programmes for ultrasound screening. The cheapest, but not the most effective, screening programme consisted of one second trimester ultrasound scan. The cost per target anomaly detected (cost effectiveness) for this programme was in the range 5,000 pound silver-109,000, pound silver but in any 1000 women it will also fail to detect between 3.6 and 4.7 target anomalies.

CONCLUSIONS

The range of uncertainty in the costs did not allow selection of any one programme as a clear choice for NHS purchasers. The results suggested that the overall allocation of resources for routine ultrasound screening in the UK is not currently economically efficient, but that certain scenarios for ultrasound screening are potentially within the range of cost effectiveness reached by other, possibly competing, screening programmes. The model highlighted the weakness of available evidence and demonstrated the need for more information both about current practice and costs.

NB4S, a member of the TBC1 domain family of genes, is truncated as a result of a constitutional t(1;10)(p22;q21) chromosome translocation in a patient with stage 4S neuroblastoma

Molecular cloning of the breakpoints of a t(1;10)(p22q21) constitutional translocation breakpoint in a patient with stage 4S neuroblastoma has identified two genes which are fused in-frame to generate a novel gene. The 1p22 gene, which we have called NB4S , encodes a 7.5 kb transcript with an 810 amino acid open reading frame and is expressed in a wide variety of tissues. NB4S has >88% homology with the mouse EVI -5 gene within the coding region and shows strong homology over a 200 amino acid region with TBC1 box motif genes involved in cell growth and differentiation. The C-teminal end of the protein contains a number of coiled coil domains, indicating a possible protein-protein binding function. The chromosome 10 breakpoint interrupts a novel transcript (TRNG10) which could only be detected in tumor cells. This transcript has no exon/intron structure or significant open reading frame, suggesting that it is a structural RNA which is transcribed but not translated. The chromosome rearrangement creates a fusion gene product which combines the TBC1 motif of NB4S with a polyadenylation signal from TRNG10 , potentially generating a truncated protein with oncogenic properties.

Chronic orofacial muscle pain: a new approach to diagnosis and management

The initial data from this study indicate that there are clearly identifiable chronic muscle pain conditions in the form of localized pain; myofascial pain or regional pain conditions; and fibromyalgia or generalized pain conditions. A clear difference exists between the prevalence of these conditions in male and female patients, with a higher percentage of female patients suffering generalized pain problems and temporomandibular problems. Generalized or localized pain appears to be an individual variant of a similar problem and pain patients may have a genetically determined vulnerability associated with bacterial toxins, particularly within the genitourinary tract. It appears that in fibromyalgia there is an underlying genetic factor that causes abnormalities in the muscle metabolic cycle, and preliminary data suggest that lipid anomalies predispose to fibromyalgia and possibly chronic fatigue syndrome. Patients report infectious events at/or around onset in more than 60 percent of cases. Seventy percent of fibromyalgic cases report orofacial pain.

[Acute vascular perforation with shunt formation in the right ventricle after percutaneous transluminal coronary angioplasty. Magnetic resonance tomography and Doppler ultrasound detection of shunt flow]

A coronary artery perforation is a rare complication after percutaneous transluminal coronary angioplasty. The therapy will be determined by the hemodynamic failure of the left or right ventricle. A case of a coronary artery perforation with a shunt from the right coronary artery to the right ventricle after coronary angioplasty is reported. The shunt was detected by coronary angiography and confirmed by magnetic resonance imaging and doppler echocardiography.

MRI using hyperpolarized noble gases

The aim of this study was to review the physical basis of MRI using hyperpolarized noble gases as well as the present status of preclinical and clinical applications. Non-radioactive noble gases with a nuclear spin 1/2 (He-3, Xe-129) can be hyperpolarized by optical pumping. Polarization is transferred from circularly polarized laser light to the noble-gas atoms via alkali-metal vapors (spin exchange) or metastable atoms (metastability exchange). Hyperpolarization results in a non-equilibrium polarization five orders of magnitude higher than the Boltzmann equilibrium compensating for the several 1000 times lower density of noble gases as compared with liquid state hydrogen concentrations in tissue and allows for short imaging times. Hyperpolarization can be stored sufficiently long (3 h to 6 days) to allow for transport and application. Magnetic resonance systems require a broadband radio-frequency system - which is generally available for MR spectroscopy - and dedicated coils. The hyperpolarized gases are administered as inhalative "contrast agents" allowing for imaging of the airways and airspaces. Besides the known anesthetic effect of xenon, no adverse effects are observed in volunteers or patients. Pulse sequences are optimized to effectively use the non-renewable hyperpolarization before it decays or is destroyed, using fast low-flip-angles strategies to allow for dynamic/breath-hold imaging of highly diffusible (He) or soluble (Xe) gases with in vivo T1-times well below 1 min. Since helium is not absorbed in considerable amounts, its application is restricted to the lung. Xe-129 is also under investigation for imaging of white matter disease and functional studies of cerebral perfusion. Magnetic resonance imaging using hyperpolarized gases is emerging as a technical challenge and opportunity for the MR community. Preliminary experience suggests potential for functional imaging of pulmonary ventilation and cerebral perfusion.

DNA vaccines expressing either the GP or NP genes of Ebola virus protect mice from lethal challenge

DNA vaccines expressing the envelope glycoprotein (GP) or nucleocapsid protein (NP) genes of Ebola virus were evaluated in adult, immunocompetent mice. The vaccines were delivered into the skin by particle bombardment of DNA-coated gold beads with the Powderject-XR gene gun. Both vaccines elicited antibody responses as measured by ELISA and elicited cytotoxic T cell responses as measured by chromium release assays. From one to four vaccinations with 0.5 microgram of the GP DNA vaccine resulted in a dose-dependent protection from Ebola virus challenge. Maximal protection (78% survival) was achieved after four vaccinations. Mice were completely protected with a priming dose of 0.5 microgram of GP DNA followed by three or four subsequent vaccinations with 1.5 micrograms of DNA. Partial protection could be observed for at least 9 months after three immunizations with 0.5 microgram of the GP DNA vaccine. Comparing the GP and NP vaccines indicated that approximately the same level of protection could be achieved with either vaccine.

Topics in microbial risk assessment: dynamic flow tree process

Microbial risk assessment is emerging as a new discipline in risk assessment. A systematic approach to microbial risk assessment is presented that employs data analysis for developing parsimonious models and accounts formally for the variability and uncertainty of model inputs using analysis of variance and Monte Carlo simulation. The purpose of the paper is to raise and examine issues in conducting microbial risk assessments. The enteric pathogen Escherichia coli O157:H7 was selected as an example for this study due to its significance to public health. The framework for our work is consistent with the risk assessment components described by the National Research Council in 1983 (hazard identification; exposure assessment; dose-response assessment; and risk characterization). Exposure assessment focuses on hamburgers, cooked a range of temperatures from rare to well done, the latter typical for fast food restaurants. Features of the model include predictive microbiology components that account for random stochastic growth and death of organisms in hamburger. For dose-response modeling, Shigella data from human feeding studies were used as a surrogate for E. coli O157:H7. Risks were calculated using a threshold model and an alternative nonthreshold model. The 95% probability intervals for risk of illness for product cooked to a given internal temperature spanned five orders of magnitude for these models. The existence of even a small threshold has a dramatic impact on the estimated risk.

Ciao 1 is a novel WD40 protein that interacts with the tumor suppressor protein WT1

The Wilms tumor suppressor protein, WT1, is a transcription factor capable of activating or repressing transcription of various cellular genes. The mechanisms involved in regulating the transcriptional activities of WT1 are beginning to be unraveled. It appears that physical interactions of other cellular proteins (p53 and par-4) with WT1 can modulate the function of WT1. Here, we report the identification and cloning of a novel WT1-interacting protein termed Ciao 1, a member of the WD40 family of proteins. Ciao 1 specifically interacts with WT1 both in vitro and in vivo. This interaction alters the mobility of a WT1.DNA complex in gel shift assays, and results in a decrease in transcriptional activation mediated by WT1. Ciao 1 does not inhibit binding of WT1 to its consensus nucleotide sequence and does not affect the repression activity of WT1. Thus, Ciao 1 appears to specifically modulate the transactivation activity of WT1 and may function to regulate the physiological functions of WT1 in cell growth and differentiation.

Molecular characterization of the 1p22 breakpoint region spanning the constitutional translocation breakpoint in a neuroblastoma patient with a t(1;10)(p22;q21)

To characterize the breakpoint in a neuroblastoma patient with a constitutional rearrangement we have constructed a yeast artificial chromosome (YAC) contig extending approximately 6 Mbp in the chromosome 1p22 region that spans the D1S435 and D1S236 loci. This contig has been confirmed by the coincidence of a number of markers in different overlapping YACs. For several of these YACs the overlap was demonstrated following the isolation and sequencing of end clones from which STS markers were generated. The majority of the YACs have been shown not to be chimeric either through the analysis of somatic cell hybrids or fluorescence in situ hybridization. Following the establishment of the contig we have been able to construct a physical map of the region that incorporates six STS and three newly assigned eSTS markers. The generation of this physical map has allowed the reordering of markers in the genetic linkage map for 1p. The physical order is; tel-D1S435-D1S188-D1S424-D1S236-D1D415- D1S420. With the reordering of D1S435 we have been able to join this contig with another reported previously, thereby generating a well characterized 15 Mbp YAC contig in the 1p22-31 region. The 6 Mbp contig described here spans the chromosome 1 constitutional translocation break-point seen in a patient with a t(1;10)(p22;q21) and who had a stage 4S neuroblastoma. YAC fragmentation has been used to define a 200 Kb region within this contig containing the 1p22 breakpoint. Restriction enzyme analysis demonstrates that there are three NotI sites in this region, one of which lies close to the translocation breakpoint site.