'Aussie normals': an a priori study to develop clinical chemistry reference intervals in a healthy Australian population.

Development of reference intervals is difficult, time consuming, expensive and beyond the scope of most laboratories. The Aussie Normals study is a direct a priori study to determine reference intervals in healthy Australian adults. All volunteers completed a health and lifestyle questionnaire and exclusion was based on conditions such as pregnancy, diabetes, renal or cardiovascular disease. Up to 91 biochemical analyses were undertaken on a variety of analytical platforms using serum samples collected from 1856 volunteers. We report on our findings for 40 of these analytes and two calculated parameters performed on the Abbott ARCHITECTci8200/ci16200 analysers. Not all samples were analysed for all assays due to volume requirements or assay/instrument availability. Results with elevated interference indices and those deemed unsuitable after clinical evaluation were removed from the database. Reference intervals were partitioned based on the method of Harris and Boyd into three scenarios, combined gender, males and females and age and gender. We have performed a detailed reference interval study on a healthy Australian population considering the effects of sex, age and body mass. These reference intervals may be adapted to other manufacturer's analytical methods using method transference.

Interaction effect of D4 dopamine receptor gene and serotonin transporter promoter polymorphism on the cortisol stress response.

Genetic variation of the serotonin transporter (SCL6A4, 5-HTT) has been associated with fear- and anxiety-related behaviors, while a polymorphism in exon III of the D4 dopamine receptor gene (DRD4) has been linked to novelty seeking. The dopaminergic and the serotonergic neurotransmitter system have been found to modulate the amygdala-connected circuitries that are crucial in emotional modulation and response to fearful stimuli. Additionally, reactivity of amygdala-innervated effector systems is also essential for our understanding of anxiety-related behaviors. Here, we used the stress-induced activation of the hypothalamic-pituitary-adrenal axis to investigate the impact of 5-HTTLPR and DRD4 on the cortisol stress response in 84 healthy adults. Saliva cortisol was measured during and after the Trier Social Stress Test. We found a significant main effect of DRD4: Carriers of the 7R allele exhibited lower cortisol responses. Additionally, a DRD4 by 5-HTTLPR interaction emerged: 5-HTTLPR LA/LA homozygotes showed a lower cortisol response than did S or LG allele carriers but only if they possessed at least one copy of the DRD4 7R allele. The results point to independent and joint effects of these polymorphisms on stress responsivity.

Reliability of intensity dependence of auditory-evoked potentials.

OBJECTIVE: Intensity dependence of auditory-evoked potentials (IAEP) is a suggested indicator of serotonergic neurotransmission. In contrast to its clinical renaissance, the reliability of IAEP has only been examined in a few studies, most of which are limited due to the possibly confounding effects of age and gender. Therefore, the present study examines different reliabilities of various IAEP parameterizations while controlling for age and gender. METHODS: Auditory-evoked potentials were recorded from 166 students. Of these 37 women and 25 men were retested after three weeks. RESULTS: Test-retest and odd-even reliabilities were remarkable at Cz in both females (r=.88/.86) and males (r=.82/.79). Reliabilities were higher in women, higher with linear than median slopes and best at Cz. Bisection of sweep number, split-half reliability, the second run, and lower intensities revealed lower reliabilities. CONCLUSIONS: Reliabilities at Cz can reach the same level as previously reported by dipole-source-localization methods, if sufficient sweep number and linear slopes are applied. SIGNIFICANCE: Based on theoretical arguments and current data, the continued use of the easy and rapidly done single-channel IAEP is suggested, although ideally in combination with multi-channel source-localization methods. This would be seminal for a drafted program standardizing IAEP to further improve its clinical utility.

Serotonin transporter gene variation impacts innate fear processing: Acoustic startle response and emotional startle.

Anxiety-related behaviors are closely linked to neural circuits relaying fear-specific information to the amygdala. Many of these circuits, like those underlying processing of innate fear, are remarkably well understood. Recent imaging studies have contributed to this knowledge by discriminating more detailed corticoamygdalar associations mediating processing fear and anxiety. However, little is known about the underlying molecular mechanisms. We used the acoustic startle paradigm to investigate the impact of molecular genetic variation of serotonergic function on the acoustic startle response and its fear potentiation. Startle magnitudes to noise bursts as measured with the eye blink response were recorded in 66 healthy volunteers under four conditions: presenting unpleasant and pleasant affective pictures as well as neutral pictures, and presenting the startle stimulus without additional stimuli as a baseline. Subjects were genotyped for functional polymorphism in the transcriptional control region of the serotonin transporter gene (5-hydroxytryptamine transporter gene-linked region: 5-HTTLPR). Analyses of variance revealed a significant effect of 5-HTTLPR on overall startle responses across conditions. Carriers of the short (s) allele exhibited stronger startle responses than l/l homozygotes. However, we could not confirm our hypothesis of enhanced fear potentiation of the startle in s allele carriers. In conclusion, the results provide first evidence that the startle response is sensitive to genetic variation in the serotonin pathway. Despite some issues remaining to be resolved, the startle paradigm may provide a valuable endophenotype of fear processing and underlying serotonergic influences.

Home based life saving skills: promoting safe motherhood through innovative community-based interventions.

In much of the developing world, home birth with unskilled attendants is the norm, and maternal and neonatal mortality rates are high. A comprehensive approach to address this problem needs to upgrade referral facilities and strengthen the skills of trained health care providers. To improve pregnancy outcomes, a program must also provide education, motivation, and mobilization of pregnant women, families, and communities (whose members must come to a common understanding of the need for and the means to prevent death of a woman or neonate). Consequently, the American College of Nurse Midwives (ACNM) has expanded the Life Savings Skills Series to include Home Based Life Saving Skills (HBLSS). HBLSS is a community and competency-based program that aims to reduce maternal and neonatal mortality by increasing access to basic life saving measures within the home and community and by decreasing delays in reaching referral facilities where life-threatening problems can be managed.

Perturbed on-off intermittency.

A basic requirement for on-off intermittency to occur is that the system possesses an invariant subspace. We address how on-off intermittency manifests itself when a perturbation destroys the invariant subspace. In particular, we distinguish between situations where the threshold for measuring the on-off intermittency in numerical or physical experiments is much larger than or is comparable to the size of the perturbation. Our principal result is that, as the perturbation parameter increases from zero, a metamorphosis in on-off intermittency occurs in the sense that scaling laws associated with physically measurable quantities change abruptly. A geometric analysis, a random-walk model, and numerical computations support the result.

Intermittency in chaotic rotations

We examine the rotational dynamics associated with bounded chaotic flows, such as those on chaotic attractors, and find that the dynamics typically exhibits on-off intermittency. In particular, a properly defined chaotic rotation tends to follow, approximately, the phase-space rotation of a harmonic oscillator with occasional bursts away from this nearly uniform rotation. The intermittent behavior is identified in several well studied chaotic systems, and an argument is provided for the generality of this behavior.

Some personal reflections on downsizing.

Downsizing, the deletion of jobs and the involuntary termination of the employees occupying those positions, has become a common and accepted corporate management tool. Although it may save money and improve a company's financial balance, it can bring with it various undesirable outcomes, including loss of loyalty and trust of personnel and degradation of the quality of the organization's product, be it a manufactured item or a service. Downsizing, as it is typically practiced, demonstrates a double standard on the part of management. The deference that employees are expected to show to employers typically is not reciprocated by companies. As a result, workers, even well-educated, professional white-collar personnel, cannot take job security for granted and must be prepared to survive a downsizing action. Front line managers usually are tasked with carrying out a downsizing action decided on at the corporate level. It is to their benefit to practice a management style that will allow them to do so in a professional manner, preserving both their credibility and the employee's dignity to the extent possible. The basic concept of downsizing is not invalid, but the manner in which it is implemented often leaves much to be desired.

Marijuana-positive urine test results from consumption of hemp seeds in food products.

Commercially available snack bars and other foodstuffs prepared from pressed hemp seeds were ingested by volunteers. Urine specimens were collected for 24 h after ingestion of the foodstuffs containing hemp seeds and tested for marijuana using an EMIT immunoassay and gas chromatography-mass spectrometry (GC-MS). Specimens from individuals who ate one hemp seed bar demonstrated little marijuana immunoreactivity, and only one specimen screened positive at a 20-ng/mL cutoff. Specimens from individuals who ate two hemp seed bars showed increased immunoreactivity, and five specimens screened positive at a 20-ng/mL cutoff. A single specimen yielded a quantitative GC-MS value (0.6 ng/mL), but it failed to meet reporting criteria. Several specimens from individuals who ate three cookies made from hemp seed flour and butter screened positive at both 50- and 20-ng/mL cutoffs. Two specimens produced quantitative GC-MS values (0.7 and 3.1 ng/mL), but they failed to meet reporting criteria. Several specimens also tested positive with an FDA-approved on-site marijuana-screening device. Hemp seeds similar to those used in the foodstuffs did not demonstrate the presence of marijuana when tested by GC-MS. In this study, ingestion of hemp seed food products resulted in urine specimens that screened positive for marijuana. No specimens gave a GC-MS quantitative value above the limit of detection for marijuana.

Splicing of intron-containing tRNATrp by the archaeon Haloferax volcanii occurs independent of mature tRNA structure.

We have investigated the requirements for mature tRNA structure in the in vivo splicing of the Haloferax volcanii, intron-containing tRNATrp RNA. A partial tRNATrp gene, which contained only the anticodon stem-loop region of the mature tRNA, was fused to a carrier yeast tRNA gene for expression in H. volcanii. Transcripts from this hybrid gene were found to be processed by endonuclease and ligase at the tRNATrp exon-intron boundaries. These results verify that the substrate recognition properties of the halobacterial endonuclease observed in vitro reflect the properties of this enzyme in vivo, namely that mature tRNA structure is not essential for recognition by the endonuclease. The independence of these reactions on mature tRNA provides further support for a relationship between archaeal tRNA and rRNA intron-processing systems and highlight a difference in the substrate recognition properties between the archaeal and eucaryal processing systems. The significance of these differences is discussed in light of the observation that the tRNA endonucleases of these organisms are related.

Properties of H. volcanii tRNA intron endonuclease reveal a relationship between the archaeal and eucaryal tRNA intron processing systems.

To better understand the relationship between archaeal and eucaryal tRNA introns and their processing systems, we have cloned the gene encoding the tRNA intron endonucleases from the archaeon H. volcanii. The gene encodes a 37 kDa protein that appears to be present as a homodimer under native conditions. Recombinant forms of this protein were expressed in E. coli and found to cleave precursor tRNAs lacking full mature tRNA structure, a property observed for the native endonuclease. Comparative sequence analysis revealed that similar proteins existed in other Archaea and that these proteins have significant similarity with two subunits of the yeast tRNA intron endonuclease. These results provide evidence that the archaeal and eucaryal tRNA intron processing systems are related and suggest a common origin for tRNA introns in these organisms.

Obstetric first aid in the community--partners in safe motherhood. A strategy for reducing maternal mortality.

The unacceptably high levels of maternal mortality that are prevalent throughout the developing world are a product of many factors; most notably, these include nonexistent, inaccessible or inadequate facility-based emergency care, poorly developed referral linkages, predominance of home-based care by attendants and family members who are poorly equipped to respond to emergencies, and the complexities of problem recognition and decision making during emergencies leading to inappropriate or delayed action. This paper describes an innovative community-oriented strategy that has been designed to reduce maternal mortality and that targets women, families, and traditional birth attendants (TBAs) using two complimentary training interventions. The strategy reflects the authors' conviction that the training of professional and paraprofessional health workers in emergency care is essential, but that it must be complemented by the education and mobilization of families, communities, and TBAs who must, in turn, come to common perceptions on the need for and means of intervening to prevent a maternal death. Collaborating with partners in the US Agency for International Development-funded Primary Providers Training and Education in Reproductive Health Project. Special Project staff of the American College of Nurse-Midwives will lead development and testing of the strategy through operations research activities in selected countries.

On-site drug testing on the rise and growing strong.

On-site workplace drug testing is fast becoming an attractive alternative to traditional methodologies. Among the reasons for its growing popularity is that these assays can be performed quickly and inexpensively by nonlaboratorians using simple equipment.

Non-pretreatment digoxin assays and developments in immunoanalyzers.

OBJECTIVE: The performance of a new, non-pretreatment digoxin assay for the Abbott IMx analyzer (Abbott Park IL) was evaluated to determine its reliability and suitability for routine clinical use. The operational characteristics of 1st, 2nd and 3rd generation immunoanalyzers are compared and contrasted. DESIGN: Within-run and day-to-day precision of the assay was determined, as well as its limit of detection. The effect of digoxin-like immunoreactive factors and carryover were evaluated. Serum from patients receiving digoxin was analyzed using the Dade Stratus II (Miami FL) digoxin test as the reference method and the IMx digoxin test as the comparison method. SETTING: An independent reference laboratory specializing in serving long-term care facilities. PATIENT POPULATION: Specimens were analyzed from geriatric patients in long-term care facilities who receive digoxin as a therapeutic drug for cardiac arrhythmias. Specimens were also tested from individuals in this same population, not receiving digoxin but demonstrating the presence of digoxin-like immunoreactive factors. MAIN OUTCOME MEASURE: Comparability of results from a new nonpretreatment digoxin with the standard digoxin assay (Stratus II) was used to determine the suitability of the new test for routine clinical use. RESULTS: The limit of detection is 0.27 ng/mL; day-to-day precision ranges from 3.4% CV to 5.9% CV. Linear regression analysis generated the following equation: IMx = 0.968 Stratus + 0.1043, r = 0.9776, n = 237. No significant interference from digitoxin-like immunoreactive factors was noted. CONCLUSION: The IMx nonpretreatment digoxin assay's performance matches the manufacturer's claims, compares favorably with another common automated digoxin test, and is suitable for routine clinical use.

Comparative analysis of ribonuclease P RNA structure in Archaea.

Although the structure of the catalytic RNA component of ribonuclease P has been well characterized in Bacteria, it has been little studied in other organisms, such as the Archaea. We have determined the sequences encoding RNase P RNA in eight euryarchaeal species: Halococcus morrhuae, Natronobacterium gregoryi, Halobacterium cutirubrum, Halobacteriurn trapanicum, Methanobacterium thermoautotrophicum strains deltaH and Marburg, Methanothermus fervidus and Thermococcus celer strain AL-1. On the basis of these and previously available sequences from Sulfolobus acidocaldarius, Haloferax volcanii and Methanosarcina barkeri the secondary structure of RNase P RNA in Archaea has been analyzed by phylogenetic comparative analysis. The archaeal RNAs are similar in both primary and secondary structure to bacterial RNase P RNAs, but unlike their bacterial counterparts these archaeal RNase P RNAs are not by themselves catalytically proficient in vitro.

The quintessence of quality in the clinical laboratory.

Providing quality service is the goal of laboratory managers. The quintessence of clinical laboratory quality is the provision of an appropriate service--either medical information or some other service--that can be shown to measurably satisfy a patient's medical need and can be tied to patient outcome. Traditional quality measures, such as laboratory inspections and proficiency testing surveys as used by CLIA'88, are not the optimal yardsticks to apply. More effective programs are needed, such as the CAP's Q-Probes, that link laboratory operations with documented desired patient outcome. Only when a laboratory can define quality in a way that allows it to be quantitatively assessed in terms of patient care can it really know if it is providing optimal service.

Cloned enzyme donor immunoassay (CEDIA) for drugs-of-abuse screening.

Large numbers of specimens (5000-18,000) were screened for amphetamines, barbiturates, cocaine, marijuana, opiates, and phencyclidine by RIA (Roche), Emit II (Syva), and a new immunoassay, CEDIA (cloned enzyme donor immunoassay, Microgenics). All immunoassays performed equivalently for cocaine, opiates, and phencyclidine. All immunoassays detected the same amphetamine/methamphetamine-positive specimens, but all also detected numerous specimens containing cross-reacting sympathomimetic amines. CEDIA detected 100%, Emit II 93%, and RIA 82% of the barbiturate-positive specimens. Emit II and CEDIA detected 86-88% of the specimens found by RIA to be marijuana positive. A subset of specimens was additionally screened by OnLine (Roche) and TDx (Abbott) for amphetamines, cocaine, and marijuana. OnLine and TDx also detected all of the amphetamine-positive specimens and numerous specimens containing cross-reacting sympathomimetic amines. All immunoassays performed equivalently for cocaine, and the four nonisotopic tests detected 86-89% of the marijuana positives found by RIA. Interfering sympathomimetic amine drug compounds can be eliminated by using an oxidizing agent, thus decreasing the number of unconfirmable amphetamine presumptive positives. The CEDIAs for all of the major drugs of abuse are reliable and effective for large-volume urine screening programs.

Limit of detection (LQD)/limit of quantitation (LOQ): comparison of the empirical and the statistical methods exemplified with GC-MS assays of abused drugs.

The limit of detection (LOD) for any analytical procedure, the point at which analysis is just feasible, may be determined by a statistical approach based on measuring replicate blank (negative) samples or by an empirical approach, consisting of measuring progressively more dilute concentrations of analyte. The limit of quantitation (LOQ), or concentration at which quantitative results can be reported with a high degree of confidence, may likewise be determined by either approach. We used both methods to determine LOD and LOQ for forensic gas chromatographic-mass spectrometric (GC-MS) analyses of abused drugs. The statistically determined LOD and LOQ values for these assays underestimated the LOD because of the large imprecision associated with blank measurements and the inability of blank samples to meet typical GC-MS acceptance criteria. The empirical method provided much more realistic LOD values, supported by reasonable experimental data, and are 0.5-0.03 the magnitude of the corresponding statistical LODs. The empirical LODs and LOQs are identical for these GC-MS assays. The observations made here about the LOD/LOQ for specific forensic GC-MS procedures are generally applicable to any type of analysis.