Angela van Daal

Assessment of DNA degradation and the genotyping success of highly degraded samples

Sheree R. Hughes-Stamm et al. — Tue, 08 Nov 2011 18:22:08 PST

DNA becomes progressively more fragmented as biological tissue degrades resulting in decreasing ability to gain a complete DNA profile. Successful identification of samples exhibiting very high levels of DNA degradation may be complicated by presenting in minute quantities. The industry standard method for human DNA identification utilising short tandem repeats (STR) may produce partial or no DNA profile with such samples. We report a comparative study of genotyping using STRs, mini-STRs and single nucleotide polymorphisms (SNPs) with template at different levels of degradation in varying amounts. Two methods of assessing quantity and quality of a DNA sample prior to genotyping were investigated. The QIAxcel capillary gel electrophoresis system provided a rapid, cost effective screening method for assessing sample quality. A real-time quantitative PCR (qPCR) assay was able to simultaneously quantify total human DNA, male DNA, DNA degradation and PCR inhibition. The extent of DNA degradation could be assessed with reasonable accuracy to 62.5 pg and genomic targets could be quantified to a lower limit of 15.6 pg. The qPCR assay was able to detect male DNA to a lower limit of 20 pg in a 1:1,000 background of female DNA. By considering the amount of DNA and the degradation ratio of a sample, a general prediction of genotyping success using AmpFlSTR® Profiler Plus®, MiniFiler¿ kits and SNP analysis can be made. The results indicate mini-STRs and SNP markers are usually more successful in typing degraded samples and in cases of extreme DNA degradation (=200 bp) and template amounts below 250 pg, mini-STR and SNP analysis yielded significantly more complete profiles and lower match probabilities than corresponding STR profiles.

Single nucleotide polymorphisms in the MATP gene are associated with normal human pigmentation variation

Justin Graf et al. — Sun, 13 Feb 2011 17:28:47 PST

Human physical pigmentation is determined by the type and amount of melanin and the process of pigmentation production probably involves more than 100 genes. A failure to synthesize melanin results in oculocutaneous albinism (OCA). A recently identified form of OCA results from mutations in the Membrane Associated Transporter Protein (MATP) gene. The role of MATP in human pigmentation is not clear. We investigated the role of two nonpathogenic nonsynonymous single nucleotide polymorphisms (SNPs) in the MATP gene to determine if they are associated with normal human skin, hair, and eye color variation. A total of 608 individuals from four different population groups (456 Caucasians, 31 Asians, 70 African-Americans, and 51 Australian Aborigines) were genotyped for c.814G>A (p.Glu272Lys) and c.1122C>G (p.Phe374Leu). Results indicate that the allele frequencies of both polymorphisms are significantly different between population groups. The two alleles, 374Leu and 272Lys, are significantly associated with dark hair, skin, and eye color in Caucasians. The odds ratios (ORs) of the LeuLeu genotype for black hair and olive skin are 25.63 and 28.65, respectively, and for the LysLys genotype are 43.23 and 8.27, respectively. The OR for eye color is lower at 3.48 for the LeuLeu and 6.57 for LysLys genotypes. This is the first report of this highly significant association of MATP polymorphisms with normal human pigmentation variation.

Forensically relevant SNP classes

Bruce Budowle et al. — Tue, 08 Feb 2011 18:36:07 PST

Forensic samples that contain too little template DNA or are too degraded require alternate genetic marker analyses or approaches to what is currently used for routine casework. Single nucleotide polymorphisms (SNPs) offer promise to support forensic DNA analyses because of an abundance of potential markers, amenability to automation, and potential reduction in required fragment length to only 60-80 bp. The SNP markers will serve an important role in analyzing challenging forensic samples, such as those that are very degraded, for augmenting the power of kinship analyses and family reconstructions for missing persons and unidentified human remains, as well as for providing investigative lead value in some cases without a suspect (and no genetic profile match in CODIS). The SNPs for forensic analyses can be divided into four categories: identity-testing SNPs; lineage informative SNPs; ancestry informative SNPs; and phenotype informative SNPs. In addition to discussing the applications of these different types of SNPs, this article provides some discussion on privacy issues so that society and policymakers can be more informed.

The DRD2 gene 957C>T polymorphism is associated with Posttraumatic Stress Disorder in war veterans

Joanne Voisey et al. — Tue, 20 Jul 2010 23:12:01 PDT

Background: Variations in genes related to the dopaminergic pathway have been implicated in neuropsychiatric disorders such as schizophrenia, substance misuse, Alzheimer's disease and Post Traumatic Stress Disorder (PTSD). A single nucleotide polymorphism (SNP) (957C>T) and a deletion polymorphism (-141delC) in the DRD2 gene and a SNP (Taq1A) in a gene directly downstream of DRD2 have all been implicated in dopamine functioning in the brain.

Methods: To test the importance of these three polymorphisms in PTSD susceptibility, a genetic screen was performed in 127 war veterans diagnosed with PTSD and 228 control individuals without a history of PTSD.

Results: No significant association was found between PTSD and the Taq1A or -141delC polymorphisms. However, a significant association was observed with PTSD and the 957C>T polymorphism. PTSD individuals were more likely to carry the C allele compared to the controls (P=0.021).

Conclusions: Our findings suggest that the 957C>T polymorphism in the DRD2 gene is one of the genetic factors for susceptibility to PTSD.

Genetics and cardiovascular disease: Design and development of a DNA biobank

Angela Van Daal — Tue, 20 Jul 2010 17:18:49 PDT

Coronary artery disease (CAD) is a complex disease with environmental and genetic determinants. Many other cardiovascular (CV) conditions also have a genetic basis. A positive family history of CV disease in first-degree relatives is a strong independent risk factor for CAD as well as several other cardiac disorders. This genetic susceptibility to CV diseases will be understood more clearly when combined with genomics, proteomics and genotyping. The Department of Cardiology at Gold Coast Hospital (Queensland, Australia) with the Faculty of Health, Science and Medicine at Bond University (Queensland, Australia) established the Gold Coast Cardiovascular DNA bank in 2006. The dataset on each individual volunteer includes coronary angiograms, clinical information (including a coronary risk factor profile), biochemical (including cardiac biomarkers) and hematological parameters, and electrocardiograms and echocardiograms. The establishment of the DNA biobank was associated with several key challenges, both technical and logistic.

Given the comprehensive nature of the information gathered, the present study has the added potential of identifying genes associated with nonischemic cardiomyopathies, valvular heart disease, congenital heart diseases and other cardiomyopathies. Pooling data from results obtained here with multiple existing DNA biobanks and registries will help in finding answers to the genetic conundrum in CV diseases. The present DNA biobank will serve as a resource well into the future as the technology and science of medical genetics evolve.

The most frequent pathology encountered in the biobank is CAD. The significance of the familial occurrence of CAD has been the focus of research for at least 50 years, with a positive family history of CV disease emerging as an independent predictor of risk in the development of CAD. By applying the knowledge learned from studies on CV genetics together with the data from the DNA biobank, scientists may be able to effectively prevent and treat CV diseases in the future.

Identification and minisequencing-based discrimination of SHV β-lactamases in nosocomial infection-associated Klebsiella pneumoniae in Brisbane, Australia

Christopher Howard et al. — Mon, 21 Sep 2009 17:18:58 PDT

Extended-spectrum B-lactamases (ESBLs) are active against oxyimino cephalosporins and monobactams. Twenty-one Klebsiella pneumoniae isolates obtained between 1991 and 1995 at the Princess Alexandra Hospital in Brisbane, Australia, were subject to amplification and sequencing of the SHV B-lactamase-encoding genes. Thirteen strains were phenotypically ESBL positive. Of these, six strains carried the blaSHV-2a gene and seven strains carried the blaSHV-12 gene. Eight strains were phenotypically ESBL negative. Of these, seven strains carried the non-ESBL blaSHV-11 gene and one strain carried the non-ESBL blaSHV-1 gene. There was complete correspondence between the ESBL phenotype and the presence or absence of an ESBL-encoding gene(s). In addition, it was determined that of the 13 ESBL-positive strains, at least 4 carried copies of a non-ESBLencoding gene in addition to the blaSHV-2a or blaSHV12 gene. A minisequencing-based assay was developed to discriminate the different SHV classes. This technique, termed “first-nucleotide change,” involves the identification of the base added to a primer in a single-nucleotide extension reaction. The assay targeted polymorphisms at the first bases of codons 238 and 240 and reliably discriminated ESBL-positive strains from ESBL-negative strains and also distinguished strains carrying blaSHV-2a from strains carrying blaSHV-12. In addition, this method was used to demonstrate an association between the relative copy numbers of blaSHV genes in individual strains and the levels of antibiotic resistance.

Novel PCR-EIA method for the detection of Chlamydia pneumoniae in respiratory specimens

J Inman-Bamber et al. — Wed, 18 Feb 2009 13:47:01 PST

We report the development of a microtitre plate-based PCR-EIA assay (ELAHA; Enzyme Linked Amplification and Hybridization Assay) for the sensitive and specific detection of Chlamydia pneumoniae in sputum samples from patients with chronic obstructive airways disease (COAD). Following PCR amplification of a segment of the chlamydial heat shock 60 protein gene, the 587 bp sized amplicon is captured onto the streptavidin coated surface of a microtitre plate using a C. pneumoniae specific biotinylated probe and the level of captured product is subsequently determined via a colorimetric reaction using an automated plate reader. The ELAHA is a simple, rapid and inexpensive method for detection of low levels of infectious agents and is readily adaptable to current clinical laboratory equipment. The assay was evaluated with a cohort of hospital respiratory patients: (i) COAD patients with acute exacerbation, (ii) COAD patients without exacerbation (stable) and (iii) a non-respiratory control group. The ELAHA produced 6/12 (50%) C. pneumoniae positives in the COAD with exacerbation group, 3/13 (23%) positives in the COAD without exacerbation group and only 1/6 (17%) positives in the control non-respiratory group. This sensitive and robust PCR-EIA method can provide clinically relevant diagnostic evidence of current C. pneumoniae infection contributing to serious respiratory tract diseases such as COAD.

Melanocortins and their receptors and antagonists

J Voisey et al. — Wed, 18 Feb 2009 13:41:00 PST

The melanocortins are a group of small protein hormones derived by post-translational cleavage of the proopiomelanocortin (POMC) gene product. The known melanocortin hormones include α-melanocyte stimulating hormone (MSH), β-MSH, γ-MSH and adrenocorticotropic hormone (ACTH). Five melanocortin receptors (MC1R through to MC5R) have been identified and most of these show tissue-specific expression patterns, as well as different binding affinities for each of the melanocortin hormones. The central melanocortin system consists of α-MSH, agouti-related protein (AGRP), MC3R and MC4R. AGRP and α-MSH are believed to be the natural antagonist and agonist respectively of MC3R and MC4R. This central melanocortin system is thought to play a fundamental role in the control of feeding and body weight. Knock-out mice models and genetic studies have pointed to the importance of the melanocortins in complex human pathways such as pigmentation, lipolysis, food intake, thermogenesis, sexual behaviour, memory and inflammatory response. Recently the melanocortins and their receptors have been the target for drug-based treatment of human physiological processes. MC3R and MC4R are likely targets for controlling body weight; MC1R may be used in the treatment of inflammation and MC2R for the treatment of glucocortical deficiency. A role for MC5R still remains unclear, but the evidence suggests an exocrine gland function.

Interrogation of multimeric DNA amplification products by competitive primer extension using Bst DNA polymerase (large fragment)

J Voisey et al. — Wed, 18 Feb 2009 13:36:51 PST

Linear dsDNA composed of tandem repeats may, be exponentially amplified by the strongly strand-displacing Bst DNA polymerase (large fragment) and two primers specific for opposite strands. When the repetitive DNA is derived from rolling circle replication of a circular template, the reaction is termed cascade rolling circle amplification (CRCA). We have developed a variant of CRCA in which one primer is attached to the surface of a microwell and the other is labeled, thus enabling detection of amplified material using an ELISA-like protocol. The circular template is derived by annealing and ligation of a padlock on target DNA. It was found that there was good correlation between the synthesis of amplified material and signal. The specificity of the reaction with respect to single-nucleotide polymorphisms was investigated, and it was found that Bst DNA polymerase is prone to extension from primers with mismatched 3' ends. Reliable single nucleotide specificity was only obtained when pre-synthesized amplified material was interrogated by competitive primer extension.

Association of functionally different RUNX2 P2 promoter alleles with BMD

James D Doecke et al. — Thu, 12 Feb 2009 12:31:55 PST

RUNX2 gene SNPs were genotyped in subjects from the upper and lower deciles of age- and weight-adjusted femoral neck BMD. Of 16 SNPs in RUNX2 and its two promoters (P1 and P2), only SNPs in the P2 promoter were significantly associated with BMD. These P2 promoter SNPs were functionally different in gel-shift and promoter activity assays.

A polymorphism in the agouti signalling protein (ASIP) is associated with decreased levels of mRNA

Joanne Voisey et al. — Thu, 12 Feb 2009 12:31:54 PST

To date, a role for agouti signalling protein (ASIP) in human pigmentation has not been well characterized. It is known that agouti plays a pivotal role in the pigment switch from the dark eumelanin to the light pheomelanin in the mouse. However, because humans do not have an agouti banded hair pattern, its role in human pigmentation has been questioned. We previously identified a single polymorphism in the 3'-untranslated region (UTR) of ASIP that was found at a higher frequency in African-Americans compared with other population groups. To compare allele frequencies between European-Australians and indigenous Australians, the g.8818A → G polymorphism was genotyped. Significant differences were seen in allele frequencies between these groups (P < 0.0001) with carriage of the G allele highest in Australian Aborigines. In the Caucasian sample set a strong association was observed between the G allele and dark hair colour (P = 0.004) (odds ratio 4.6; 95% CI 1.4–15.27). The functional consequences of this polymorphism are not known but it was postulated that it might result in message instability and premature degradation of the transcript. To test this hypothesis, ASIP mRNA levels were quantified in melanocytes carrying the variant and non-variant alleles. Using quantitative real-time polymerase chain reaction the mean ASIP mRNA ratio of the AA genotype to the AG genotype was 12 (P < 0.05). This study suggests that the 3'-UTR polymorphism results in decreased levels of ASIP and therefore less pheomelanin production. © 2006 Blackwell Synergy

Gene polymorphisms and their effects in the melanocortin system

Levi J. Carroll et al. — Thu, 12 Feb 2009 12:31:54 PST

In addition to its role in human pigmentation, components of the melanocortin system regulate appetite, energy homeostasis and hormone production. Recent studies have suggested possible roles of this system in immunity, transmission of pain signals, and reproductive potential. A number of polymorphisms have been identified in genes of the melanocortin system and are associated with pigmentation in humans, as well as being causative of disorders of adrenal hormone production and obesity. This review gives an outline of these polymorphisms, their functional significance and possible application to or impact on diagnosis and pharmacotherapy based on melanocortin pathways.

Linkage disequilibrium analysis identifies an FGFR1 haplotype-tag SNP associated with normal variation in craniofacial shape

Angela Van Daal et al. — Thu, 12 Feb 2009 12:31:54 PST

Mutations in FGFR1 and TWIST1 have been reported to affect the timing of calvarial suture fusion resulting in craniosynostosis and facial abnormalities. We screened nonpathologic populations for genetic polymorphisms that may associate with normal craniofacial variation. We identified 17 single-nucleotide polymorphisms (SNPs) in FGFR1, 6 of which were novel (g.8591855G→A, g.8593685G→A, g.8602303C→T, g.8602475A→G (p.Ile293Val), g.8605849C→T, g.8607868G→A). No SNPs were found in TWIST1. FGFR1 SNP haplotypes were reconstructed for Caucasian, Asian, Australian Aboriginal, and African American populations. All populations shared two linkage disequilibrium blocks, with one haplotype-tag SNP (htSNP) tagging each block. The htSNP g.8592931G→C was found to have a significant negative correlation with the cephalic index for all populations (R = −0.187, p = 0.036), with larger correlations in Asians and females. This finding is a starting point in the identification of a set of SNPs that can be genotyped to determine both normal and disease craniofacial phenotypes.

Mouse models of obesity

Carroll Levi et al. — Thu, 12 Feb 2009 12:31:52 PST

Insights into the etiology of human obesity have arisen from the study of animal models. Animal models of obesity are also important for the development of future treatments of obesity. An agouti mouse mutation resulting in obese, yellow mice was described over a century ago and in 1992 agouti was cloned, making it the first obesity gene characterized at the molecular level. The lethal yellow mouse mutation is one of five dominant agouti mutations and is an excellent model for human obesity. The molecular categorization of agouti was responsible for the elucidation of the melanocortin system's involvement in hypothalamic weight regulation. As genetic knowledge increases many transgenic mice have been created with genes either over-expressed or deleted, models which further enhance the understanding of obesity.

A polymorphism study of the human agouti gene and its association with MC1R

Joanne Voisey et al. — Thu, 12 Feb 2009 12:31:52 PST

To determine whether the Agouti Signalling Protein (ASP) gene is associated with skin and hair coloration in humans, the complete coding region of ASP was screened for polymorphisms. Analysis of ASP in Caucasian, African-American, Spanish Basque, Hispanic, Apache and Australian Aboriginal populations revealed no amino acid substitutions. A single polymorphism in the 3' untranslated region occurred at a frequency of 0.2 in African-Americans. Variants of the Melanocortin 1 Receptor (MC1R) gene have been found to be associated with red hair and fair skin in humans. Red hair individuals are usually compound heterozygotes or homozygous for one of a number of MC1R polymorphisms associated with red hair. Some individuals however are heterozygous for only one of these polymorphisms and dizygotic twins can be concordant for MC1R variants but discordant for hair colour. A recent study has also identified rare redheads carrying no MC1R variants indicating that polymorphisms of the human MC1R gene are required but not sufficient for the red hair phenotype. To address the question of whether ASP also contributes to the red hair phenotype, individuals previously identified as having unexpected MC1R genotypes were screened for polymorphisms at the ASP locus. No polymorphisms were found in any of these individuals. Results indicate that the human ASP gene is unlikely to function in normal human pigmentation in the same way as MC1R.

The C/C genotype of the C957T polymorphism of the dopamine D2 receptor (DRD2) is associated with schizophrenia

Bruce R. Lawford et al. — Thu, 12 Feb 2009 12:31:51 PST

The T allele of the human dopamine D2 receptor (DRD2) gene C957T polymorphism is associated with reduced mRNA translation and stability. This results in decreased dopamine induced DRD2 upregulation and decreased in vivo D2 dopamine binding. Conversely, the C allele of the C957T polymorphism is not associated with such changes in mRNA leading to increased DRD2 expression. PET and postmortem binding studies show that schizophrenia is often associated with increased DRD2 availability. We report that on the basis of comparing the frequencies of the C/C and T/T genotypes of 153 patients with schizophrenia and 148 controls that schizophrenia is associated with the C/C genotype. The C957T shows a population attributable risk for schizophrenia of 24% and an attributable risk in those with schizophrenia of 42%. Increased expression of D2 receptors associated with the C allele is likely to be important in the underlying pathophysiology of at least some forms of schizophrenia. Enhanced understanding of schizophrenia afforded by this finding may lead to advances in treatment and prevention.

Body mass index-related human adipocyte agouti expression is sex-specific but not depot-specific

Joanne Voisey et al. — Thu, 12 Feb 2009 12:31:51 PST

OBJECTIVE: To determine if human adipocyte agouti signal protein (ASIP) mRNA expression is associated with obesity and is gender and/or depot specific. RESEARCH METHODS AND PROCEDURES: Subjects included 8 men (64 +/- 3 years) and 14 women (56 +/- 15 years) undergoing elective abdominal surgery. ASIP mRNA levels in isolated omental and subcutaneous abdominal adipocytes were measured by quantitative reverse transcription polymerase chain reaction. RESULTS: No significant depot difference was observed between genders; ASIP mRNA levels of omental and subcutaneous abdominal adipocytes were pooled for this analysis. BMI and ASIP gene expression were negatively correlated in men (rho = -0.70; p < 0.05), whereas a positive relationship was observed in women (rho = 0.48; p < 0.05). No significant difference was observed in age, body weight, body mass index (BMI), and waist circumference between groups. Hip circumference was significantly higher in women than in men (p < 0.05). Also, no significant difference in ASIP mRNA expression was observed between men and women, regardless of the fat depot. DISCUSSION: These results show that men and women of similar age and BMI present similar ASIP mRNA levels in omental and subcutaneous abdominal adipocytes. However, a sexual dimorphism exists in the relationship between ASIP expression and BMI. If ASIP is involved in appetite regulation or energy homeostasis in humans, this observation may contribute to the recognized differences in these parameters between men and women.

Agouti: From mouse to man, from skin to fat

Joanne Voisey et al. — Thu, 12 Feb 2009 12:31:51 PST

The agouti protein regulates pigmentation in the mouse hair follicle producing a black hair with a subapical yellow band. Its effect on pigmentation is achieved by antagonizing the binding of alpha-melanocyte stimulating hormone (alpha-MSH) to melanocortin 1 receptor (Mc1r), switching melanin synthesis from eumelanin (black/brown) to phaeomelanin (red/yellow). Dominant mutations in the non-coding region of mouse agouti cause yellow coat colour and ectopic expression also results in obesity, type 11 diabetes, increased somatic growth and tumourigenesis. At least some of these pleiotropic effects can be explained by antagonism of other members of the melanocortin receptor family by agouti protein. The yellow coat colour is the result of agouti chronically antagonizing the binding of alpha-MSH to Mc1r and the obese phenotype results from agouti protein antagonizing the binding of alpha-MSH to Mc3r and/or Mc4r. Despite the existence of a highly homologous agouti protein in humans, agouti signal protein (ASIP), its role has yet to be defined. However it is known that human ASIP is expressed at highest levels in adipose tissue where it may antagonize one of the melanocortin receptors. The conserved nature of the agouti protein combined with the diverse phenotypic effects of agouti mutations in mouse and the different expression patterns of human and mouse agouti, suggest ASIP may play a role in human energy homeostasis and possibly human pigmentation.

Agouti signal protein regulation in human melanoma cells

Joanne Voisey et al. — Thu, 12 Feb 2009 12:31:50 PST

Production of the pigment eumelanin is controlled by α-melanocyte stimulating hormone (α-MSH) stimulation of melanocortin 1 receptor (Mc1r), whereas production of pheomelanin results from agouti antagonism of α-MSH signalling through Mc1r. The role of agouti in mouse pigmentation has been extensively investigated but a role for agouti signalling protein (ASIP) in human pigmentation has not been determined. To determine whether ASIP regulates known melanogenic genes in humans, ASIP was over-expressed in a human melanoma cell line. Levels of mRNA and protein were measured in genes known to be up or down-regulated by agouti in the mouse, namely microphthalmia (Mitf), tyrosinase (Tyr), tyrosinase-related protein 1 (Tyrp1), dopachrome tautomerase (Dct), Mc1r , silver , initiation transcription factor 2 (Itf2) and mini chromosome maintenance protein 6 (Mcm6). These melanogenic genes were not found to be significantly up or down-regulated by ASIP at the transcriptional level in human melanoma cells. However, ASIP down-regulation of tyrp1 was observed at the translational level. To identify novel genes that may be regulated by ASIP in melanoma cells, microarrays were used to determine differences in gene expression between the control and ASIP transfected melanoma cells. The expression level of human RNAs were determined by microarray analysis using a 19 200 cDNA and a 19 200 oligonucleotide array representing 13 000 and 18 864 individual genes, respectively. Genes observed to be modulated by ASIP were confirmed by quantitative real-time polymerase chain reaction. Results identify five genes, namely PPARβ , eIF-4B , RRM2 , MINOR and EVI2B that are down-regulated by ASIP, indicating a likely role for ASIP in human melanogenesis.

Solid-phase amplification and detection: A single-tube diagnostic assay for infectious agents

Maria Somodevilla-Torres et al. — Thu, 12 Feb 2009 12:31:49 PST

BACKGROUND: We report the development of an enzyme-linked immunosorbent assay[mdash ]like single-tube assay for the detection of infectious agents in a microtiter tray format. METHODS AND RESULTS: The method, sequential nucleic acid amplification and capture (SNAAC), combines amplification with hybridization of the product to a surface/matrix-bound oligonucleotide probe. After amplification of the target sequence using species-specific primers, one of which contains a detection tag such as fluorescein or biotin, a denaturation and hybridization cycle is performed. This allows capture by an oligonucleotide that is covalently bound to the surface of a microtiter tray well or other support. After washing to remove unincorporated solution-phase oligonucleotide bearing the detection tag, the level of captured product is determined through a colorimetric reaction using an automated plate reader. We show the value and utility of the SNAAC detection method using cloned sequences of the important human respiratory pathogen Chlamydia pneumoniae. CONCLUSIONS: SNAAC is a simple, rapid, and inexpensive method for the detection of low levels of infectious agents that is readily adaptable to current clinical laboratory equipment, thus avoiding the need to develop or purchase new instrumentation.