Deoxyribonucleic Acid Technology Research Articles

Forensic DNA database and criminal investigation in the Sahel region, a need to update the National Security Policy?

Abstract Ongoing terrorist attacks in the Sahel region call for strengthening the security system by using human deoxyribonucleic acid (DNA) identification technology. In this context, public opinion must be considered when establishing solid standards and universal safeguards for one of the most invasive forms of surveillance and profiling. For this purpose, we gathered Internet users’ opinions in Burkina Faso (BF, a country located in the Sahel region) on the use of DNA technology to support criminal investigations. The results revealed that 91.7% (431) of the 470 participants believed that this technology is currently necessary for the BF’s criminal justice system. However, the respondents expressed concerns about the custody and management of a national forensic DNA database (NFDD). In this particular security setting, the public opinion of this study may provide leaders and political policymakers with clues for considering genetic fingerprints and implementing an NFDD to support criminal investigations in BF while also considering the ethical implications.

DNA technology for big data storage and error detection solutions: Hamming code vs Cyclic Redundancy Check (CRC)

There is an increasing need for high-capacity, highdensity storage media that can retain data for a long time, due to the exponential development in the capacity of information generated. The durability and high information density of synthetic deoxyribonucleic acid (DNA) make it an attractive and promising medium for data storage. DNA data storage technology is expected to revolutionize data storage in the coming years, replacing various Big Data storage technologies. As a medium that addresses the need for high-latency, immutable information storage, DNA has several potential advantages. One of the key advantages of DNA storage is its extraordinary density. Theoretically, a gram of DNA can encode 455 exabytes, or 2 bits per nucleotide. Unlike other digital storage media, synthetic DNA enables large quantities of data to be stored in a biological medium. This reduces the need for traditional storage media such as hard disks, which consume energy and require materials such as plastic or metals, and also often leads to the generation of electronic waste when they become obsolete or damaged. Additionally, although DNA degrades over thousands of years under non-ideal conditions, it is generally readable. Furthermore, as DNA possesses natural reading and writing enzymes as part of its biological functions, it is expected to remain the standard for data retrieval in the foreseeable future. However, the high error rate poses a significant challenge for DNA-based information coding strategies. Currently, it is impossible to execute DNA strand synthesis, amplification, or sequencing errors-free. In order to utilize synthetic DNA as a storage medium for digital data, specialized systems and solutions for direct error detection and correction must be implemented. The goal of this paper is to introduce DNA storage technology, outline the benefits and added value of this approach, and present an experiment comparing the effectiveness of two error detection and correction codes (Hamming and CRC) used in the DNA data storage strategy.

Systematic Review on Implication for DNA Assisted Technology into Molecular Medicine and the useful is the application of Genome Wide Studies

Objective: The aim of this study is to explore the role of molecular DNA, DNA Phenotyping and Polymerase Chain Reaction in samples relevant to genetic investigation. The Deoxyribonucleic Acid (DNA) is a macromolecule which has propelled our capacity of understanding the function of an organism at the cellular level, how organism reproduce and replicate, and pass their subjective genetic information from one generation to the other. DNA is also referred to as the genetic “Blueprint” of an organism and found to possess all information pertaining to the specific being. Nuclear DNA is present within the nucleus and is significant in developing immunity for the cell and depends on the information incorporated within its framework. Mitochondrial DNA exists in varying locations in frequencies of two to ten copies within mitochondria. The most familiar body fluids come across in molecular medicine laboratories is blood, semen and saliva and further more are vaginal fluids, urine and sweat. Bones, teeth, soft tissues etc. are also essential biomarkers for DNA-phenotyping. Methodology: The methods for research for this particular study is to demonstrate a review of relevant literature to examine the molecular genetics and the application of genome and DNA-amplification into molecular medicine investigations. To conduct a literature review a qualitative research design is the most suitable research design. It provides the rationale for assessing the human behaviour and assists to legalize and authenticate the data which is selectively collected from the secondary sources. Results: Every individual’s DNA consists of minor alterations a change in these restriction places would result in different profile of restriction fragments. Genome wide population substructure is large enough to determine ancestry with large number of Autosomal SNPs at the level of continental resolutions. Conclusion: The advances in human genomics and molecular genetics have provided success and advances by determining the cellular origin and estimating the age of sample and disposition time. The Phenotypical characteristics like hair and eye color demonstration in criminal cases has yielded better inferences however, DNA phenotyping illustrates a limited approach wherein incorporated into biological material analysis. The accuracy of DNA technology is incredibly useful for professionals like lawyers, anthropologists, homicide detectives etc. in the field of molecular medicines and is expected to improve in years to come. Key Words; Deoxyribonucleic Acid (DNA) , Polymerase Chain Reaction (PCR), Mitochondrial DNA (mtDNA) sequencing and Short Tardem Repeat (STR)

VARIOUS REGULATIONS ON THE EXISTENCE OF N-TH ORDER LIMIT LANGUAGE

In molecular biology, recombinant Deoxyribonucleic acid technology has ignited an increase in the interest of new researches. Moreover, the splicing system has generated enthusiasm in developing computational models collaborating with formal language theory. Formal language theory tends to be a natural structure for formalising and investigating DNA computing models from this viewpoint. The work of several researchers who added control structures to the splicing formalism, thus creating universal computation systems, has provided additional inspiration for the study of splicing systems. A splicing system is a conventional model of a set of dsDNA that undergoes the cutting and pasting process with the presence of restriction enzyme and ligase. Previously, an introduction of the n-th order limit language is presented and discussed. The properties and the characteristics of the n-th order limit language are developed and also explained by using examples and sort into a few cases. However, the regulation of the existence of the n-th order limit language is left unintended. In this paper, the factors that restrict the formation of the n-th order limit language are discussed. Several restrictions applied are the length of the rules are not equal and same rules applies on several crossing sites of the initial strings. In addition, some examples are given to show the restriction of the formation of n-order limit language.

Asymmetric DNA encryption and decryption technique for Arabic plaintext

The security of transmitting information from one point to another through different media is an important issue in the modern digital society. Researchers have consistently developed and proposed modern data transfer systems in order to transfer data in a safe manner. DNA (deoxyribonucleic acid) based encryption technology is a new encryption model used to protect data during transmission. Current systems that use DNA technology to encrypt Arabic texts are virtually non-existent and intended to hide data rather than encrypting it (i.e., steganography). In this research, an asymmetric DNA encryption technology is offered to encrypt and decrypt simple Arabic scripts. This technology depends on the integrity between asymmetric cryptography (i.e. RSA algorithm), dynamic encoding, and data dependency with the scope of DNA computing technology. Asymmetric cryptosystem is used only to begin the process of encryption and decryption, which is then processed fully using DNA computing. The idea of the proposed algorithm aims to generate a dynamic DNA table that depend on plain text, that aims to generate a dynamically generating 14 circular keys based on a multi-level security. Here, JAVA platform is used to implement the proposed work, and the randomization and avalanche effect are used to prove the efficiency of the proposed algorithm. This technique provides a significant change in the encoded text with an average of 53% of the avalanche characteristic.

The Health Effects of Genetically Modified Foods: a Brief Review

Genetically modified foods are organisms (i.e. plants or animals) in which the genetic material (Deoxyribonucleic Acid) has been altered in a way that does not occur naturally by mating and/or natural recombination. Combining genes from different organisms is known as recombinant Deoxyribonucleic Acid technology and the resulting organism is said to be ‘Genetically Modified’, ‘Genetically Engineered’ or ‘Transgenic’. Crops grown commercially and/or field-tested are resistant to a virus that could destroy most of the African harvest, other crops with increased iron and vitamins that may alleviate chronic malnutrition and a variety of plants that are able to survive weather extremes. There are fruits that produce human vaccines against infectious diseases such as hepatitis B, fish that mature more quickly, fruit and nut trees that yield years earlier and plants that produce new plastics with unique properties. Controversies and public concern surrounding Genetically Modified foods and crops commonly focus on human and environmental safety, ethics, food security, poverty reduction and environmental conservation. With this new technology on gene manipulation there are the risks of tampering with nature, effects will have on the environment, the health concerns that consumers should be aware of, and effects related with recombinant technology. This review addresses the major concerns about the safety, environmental and legal issues which are collectively infer health hazards of Genetically Modified foods and recombinant technology in different perspective.

Silver-coated silicon nanowire platform discriminates genomic DNA from normal and malignant human epithelial cells using label-free Raman spectroscopy

Genomic deoxyribonucleic acid (DNA) stores and carries the information required to maintain and replicate cellular life. While much efforts have been devoted in decoding the sequence of DNA basis to detect the genetic mutations related to cancer disease, it is becoming clear that physical properties, like structural conformation, stiffness and shape, can play an important role to recognize DNA modifications. Here, silver-coated silicon nanowires (Ag/SiNWs) are exploited as Raman spectroscopic platform to easily discriminate healthy and cancer genomic DNA, extracted from human normal skin and malignant melanoma cells, respectively. In particular, aqueous DNA droplets are directly deposited onto a forest of Ag/SiNWs and Raman maps are acquired after sample dehydration. By applying principal component analysis (PCA) to the Raman spectra collected within the droplets, healthy and cancer cell DNA can be distinguished without false negative identifications and with few false positive results (< 2%). The discrimination occurs regardless the analysis of specific DNA sequencing, but through Raman bands strictly related to the interfacing of the DNA and the NWs. The observed phenomenon can be ascribed to conformational differences and/or diverse charge properties between healthy and cancer cell DNA determining a different arrangement of the molecules adsorbed onto the NWs upon water evaporation. The unique interaction with DNA and facile fabrication technology make Ag/SiNWs an effective platform for a robust, rapid and label-free cancer diagnosis, as well as a potential tool to investigate physical properties of DNA.

Further evaluation of recombinant Tsol-p27 by enzyme-linked immunoelectrotransfer blot for the serodiagnosis of cysticercosis in pigs from Mozambique

BackgroundPorcine cysticercosis has a negative impact on human health and the meat industry, as it makes infected meat unaproprieted for consuption and it is the main etiology of epileptic seizures in developing countries. There are multiple serological assays that use crude antigens with high sensitivity and specificity for the diagnosis of both porcine and human cysticercosis. Nonetheless, antigen preparation is time-consuming, needs a well-equipped laboratory and trained personnel and places those manipulating the meat at great risk for infection. New serodiagnostic approaches to the diagnosis of porcine and human cysticercosis have been directed towards the development of recombinant deoxyribonucleic acid technology for the generation of synthetic proteins that can serve as simplified, low-cost and harmless substitutes for native antigens. The aim of the present study was to further evaluate the recombinant Tsol-p27 protein as a target molecule in immunoassays for the serodiagnosis of porcine cysticercosis. From these data, we hoped to develop recommendations regarding its use in the serodiagnosis of porcine cysticercosis.ResultsWe studied a panel of 83 naturally infected pig sera from Angónia District, Mozambique, an endemic area for porcine and human cysticercosis. These sera were previously tested by antigen enzyme-linked immunosorbent assay (Ag-ELISA) to detect antigens of T. solium. The serum panel was processed by enzyme-linked immunoelectrotransfer blot (EITB) assay against the recombinant Tsol-p27 protein and the Ag-ELISA assay results were used to compare and evaluate the performance of Tsol-p27 for the diagnosis of cysticercosis. Out of 83 sera, 24 (29.0%) were positive for Tsol-p27 and 59 (71%) were negative in the same assay. From the 37 sera that tested positive to Ag-ELISA, 11 (13.3%) were positive to Tsol-p27, while from 46 sera that tested negative to Ag-ELISA, 33 (39.7%) also tested negative to Tsol-p27. The sensitivity and specificity of Tsol-p27 was 29.7% and 71.7%, respectively, while the positive predictive value and negative predictive value were 45.8% and 55.9%, respectively, as calculated using Medcalc® version 15.0 software (MedCalc Software, Ostend, Belgium).ConclusionWhile Tsol-p27 recombinant protein might be suitable for testing human sera, its performance in pigs is not acceptable, so other recombinant proteins should be evaluated alone or multiplexed.

Non-invasive prenatal testing - a new method in improving first trimester screening for chromosome-related abnormalities

In the last 15 years, major advances have been made in prenatal screening. Cohort studies have led to an understanding of the causes of many common diseases that are determined by the combined effects of genetic and phenotypic factors. Non-invasive prenatal testing (NIPT) is a technology used to isolate deoxyribonucleic acid (DNA) placental fragments from the mother’s blood at as early as 10 weeks of gestation, using cell free fetal DNA technology. NIPT screens for trisomy 13,18 and 21 for sex chromosome abnormalities with a high detection rate. Cohort studies have shown a high detection rate and a low false positive rate for NIPT, but it is still considered a screening test and not diagnostic. It is recommended confirmation in case of a positive test, with a diagnostic procedure as chorionic villus sampling or amniocentesis. It is essential that NIPT be used ethically and effectively. Because of its high sensitivity (true positive rate) and its specificity (true negative rate) many recommend that NIPT should be used as a diagnostic method. However, today NIPT is used as a screening method, an attractive alternative to the serum screens and invasive test currently in use. There is a continuing decline in sequencing costs and hopefully, soon, the cost will be reduced.

Amplification of Portions of IGF-I and Insulin Genes and Characterisation of Variation in the Coding Sequence of Helmeted Guinea Fowl Numida meleagris

The study was undertaken to characterise and identify the insulin like growth factor-I (IGF-I) and insulin genes in five varieties (Ash, Black, Pearl Ash, Pearl Black and White) of local helmeted guinea fowl using DNA technology. Deoxyribonucleic acid (DNA) was purified from blood samples of the five varieties and Polymerase Chain Reaction (PCR) amplification of DNA done with primers designed to amplify the two genes; insulin-like growth factors I (IGF-I) and insulin (I). Purification of PCR product and dye terminator sequencing was also carried out using samples prepared and loaded into the Beckman Taq capillary sequencer. IGF-I gene profiles of Pearl Ash, White, Ash, Black varieties were similar (83 percent); and insulin gene profile of Pearl Ash, Ash, Black, Pearl Black varieties were 91 percent similar.

Role of deoxyribonucleic acid technology in forensic dentistry

In the last few years, Deoxyribonucleic Acid (DNA) analysis methods have been applied to forensic cases. Forensic dental record comparison has been used for human identification in cases where destruction of bodily tissues or prolonged exposure to the environment has made other means of identification impractical, that is, after fire exposure or mass disaster. Teeth play an important role in identification and criminology, due to their unique characteristics and relatively high degree of physical and chemical resistance. The use of a DNA profile test in forensic dentistry offers a new perspective in human identification. The DNA is responsible for storing all the genetic material and is unique to each individual. The currently available DNA tests have high reliability and are accepted as legal proofs in courts. This article gives an overview of the evolution of DNA technology in the last few years, highlighting its importance in cases of forensic investigation.

SUBKLONING DAN ISOLASI GEN PENYANDI MIKRONEMA 3 (MIC-3) Toxoplasma gondii ISOLAT LOKAL

Microneme protein (MIC) is one of proteins that belongs to excretory-secretory antigens (ESAs) of Toxoplasma gondii. Microneme 3 protein (MIC-3) is the protein that plays an important role in the invasion proccess during cell infection as a mediator attachment parasite to the host cell. The aim of this research is to clone mic3 (gene encoding for MIC-3) of T. gondii from local isolate using recombinant DNA technology by cloning mic3 in an expression vector. Deoxyribonucleic acid (DNA) from T. gondii tachyzoites was amplified by PuRe Taq RTG-PCR Beads using mic3 specific primers. Amplified DNA was double digested using EcoRV and HindIII restriction endonucleases and then purified using EZ-10 spin coloumn purification kit. The mic3 DNA was ligated into pET-32a(+) expression vector and transformated into Escherichia coli BL21. The results showed that recombinant mic3gene 4.2 kDa has been successfully performed by cloning gene encoding for MIC-3 protein of T. gondii local isolate into pET-32a(+) and transformed to E. coli BL21.

DNA Marking and Authentication: A unique, secure anti-counterfeiting program for the electronics industry

DNA (deoxyribonucleic acid) is a form of forensic evidence trusted by law enforcement and recognized by international courts around the world. This abstract provides an introduction to the utility of botanical DNA taggants to provide supply chain security for electronic components and to protect against counterfeiting and diversion. A detailed treatment of the science behind Applied DNA Sciences’ (APDN’s) botanical DNA technology, its applications to semiconductors and microchips and an overview of DNA analysis by Polymerase Chain Reaction (PCR) and Cell Electrophoresis (CE) analysis is provided. In addition, we draw an outline of a marking and authentication program as it might be implemented in a microchip supply chain environment, as an indicator of its efficacy against current known counterfeiting strategies.

Monoclonal antibodies as diagnostics; an appraisal

Ever since the development of Hybridoma Technology in 1975 by Kohler and Milstein, our vision for antibodies as tools for research for prevention, detection and treatment of diseases, vaccine production, antigenic characterization of pathogens and in the study of genetic regulation of immune responses and disease susceptibility has been revolutionized. The monoclonal antibodies being directed against single epitopes are homogeneous, highly specific and can be produced in unlimited quantities. In animal disease diagnosis, they are very useful for identification and antigenic characterization of pathogens. Monoclonal antibodies have tremendous applications in the field of diagnostics, therapeutics and targeted drug delivery systems, not only for infectious diseases caused by bacteria, viruses and protozoa but also for cancer, metabolic and hormonal disorders. They are also used in the diagnosis of lymphoid and myeloid malignancies, tissue typing, enzyme linked immunosorbent assay, radio immunoassay, serotyping of microorganisms, immunological intervention with passive antibody, antiidiotype inhibition, or magic bullet therapy with cytotoxic agents coupled with anti mouse specific antibody. Recombinant deoxyribonucleic acid technology through genetic engineering has successfully led to the possibility of reconstruction of monoclonal antibodies viz. chimeric antibodies, humanized antibodies and complementarily determining region grafted antibodies and their enormous therapeutic use.

Crime Scene Genetics: Transforming Forensic Science through Molecular Technologies

ABSTRACT Advances in DNA (deoxyribonucleic acid) technology over the past 25 years have led to spectacularly precise forensic identification techniques, although some applications have also unleashed controversies regarding genetic privacy. Current molecular forensic work is pushing these technologies even further by analyzing extremely damaged DNA and by introducing RNA (ribonucleic acid) techniques to forensics.

Perspectives of biotechnological production of l-tyrosine and its applications

The aromatic amino acid L-tyrosine is used as a dietary supplement and has promise as a valuable precursor compound for various industrial and pharmaceutical applications. In contrast to chemical production, biotechnological methods can produce L-tyrosine from biomass feedstocks under environmentally friendly and near carbon-free conditions. In this minireview, various strategies for synthesizing L-tyrosine by employing biocatalysts are discussed, including initial approaches as well as more recent advances. Whereas early attempts to engineer L-tyrosine-excreting microbes were based on auxotrophic and antimetabolite-resistant mutants, recombinant deoxyribonucleic acid technology and a vastly increasing knowledge of bacterial physiology allowed recently for more targeted genetic manipulations and strain improvements. As an alternative route, L-tyrosine can also be obtained from the conversion of phenol, pyruvate, and ammonia or phenol and serine in reactions catalyzed by the enzyme tyrosine phenol lyase.

Engineering of the Extracellular Matrix: Working toward Neural Stem Cell Programming and Neurorestoration— Concept and Progress Report

In the concept of neurorestoration, cellular and structural elements that have been lost are replaced, and their function is restored. Central to this therapeutic strategy is the transplantation of neural progenitor cells such as clonogenically expanded stem cells. Stem cells make decisions regarding fate and patterning in response to external environmental signals. The therapeutic effectiveness of neural stem cells may be facilitated by the ability to manipulate these signals in a temporal and spatially appropriate fashion. Artificial deoxyribonucleic acid and artificial protein technology combines elements of protein engineering, molecular biology, and recombinant deoxyribonucleic acid technology to produce proteins with functional domains derived from naturally occurring proteins and represents a potentially powerful tool to modulate stem cell behavior. To this end, we have developed three artificial extracellular matrix proteins that incorporate the active domain of hJagged1 and hDelta1 into an elastin backbone. hJagged1 and hDelta1 are members of the DSL family of ligands to the Notch receptor, a signaling system that is very important in development and is the strongest known signal to instruct neural progenitor cells to choose glial fates over neuronal fates. The successful cloning of the artificial genes was confirmed by test digestions with appropriate restriction enzymes as well as direct deoxyribonucleic acid sequencing. In addition, we have demonstrated that all three artificial extracellular matrix proteins express at a high level in a prokaryotic host. This report describes the concept and progress in an entirely novel and previously unreported approach to modulate neural stem cell behavior. Its future application could include in vitro processing of stem cells before transplantation, supporting and programming the cells after transplantation, as well as the development of bioactive biomaterials.

Overview of bone morphogenetic proteins.

A literature review was conducted. To review the discovery of the bone morphogenetic proteins and describe the bone morphogenetic protein products that will or may be available for clinical use. Bone morphogenetic proteins comprise the osteoinductive component of several tissue engineering products in late-stage development as replacements for autogenous bone graft, and for bone augmentation and repair. The literature on bone morphogenetic proteins was reviewed. Bone morphogenetic proteins were discovered originally on the basis of their presence in osteoinductive extracts of bone matrix. Molecular cloning of bone morphogenetic proteins demonstrated that they are a family of related differentiation factors, each capable of inducing the formation of new bone tissue when implanted. Two of the molecules in clinical use, recombinant human bone morphogenetic protein-2 and recombinant human bone morphogenetic protein-7 (OP-1) are produced in a biotechnology process using recombinant deoxyribonucleic acid technology that offers unlimited supply and substantial control over purity and reproducible activity. A third material, bovine bone morphogenetic protein extract, is extracted from bone, and contains a mixture of bone morphogenetic protein molecules. Each of these molecules, although osteoinductive in vivo, has different physiologic roles and biologic activities in vivo and in vitro. Successful development of a product for use in spinal fusion involves selecting the osteoinductive molecule, the amount of the bone morphogenetic protein required, and the method of delivery, as well as conducting subsequent preclinical and clinical studies to evaluate its efficacy and safety. On the basis of the data provided in this issue of Spine, some of these bone morphogenetic protein-based products provide for revolutionary therapies in orthopedic practice.

Biotechnology: reality or dream

The development of molecular biology and molecular genetics, especially of the recombinant DNA technology enabled improvement of experimental methods that provide manipulation within a cell-free system, such as cell and tissue cultures. Such methods resulted in the development of different new technologies with specific properties in relation to the conventional definitions. According to PERSLEY and lantin (2000) the following components are essential for the contemporary biotechnology: (i) genomics - a molecular characterization of all genes and gene products of an organism (ii) bioinformatics - the assembly of data from genomic analysis into accessible forms; (iii) transformation - the introduction of genes controlling a trait of interest into a genome of a desired organism (micro organisms, plants, animal systems). By the application of cotemporary biotechnology new methods in the field of diagnostic are developed such as rapid and more accurate identification of the presence and absence of genes in the genome of the organism of interest (identification of pathogens prenatal diagnostics, molecular markers assisted breeding for plants, etc). The traits of an organism are determined by its genetic material, i.e. by a molecule of deoxyribonucleic acid (DNA). watson and crick (1953) were the first scientists to describe the structure of DNA as a double-stranded helix. Higher organisms contain a set of linear DNA molecules - chromosomes and a full set of chromosomes of an organism is a genome. Each genome is divided into a series of functional units, i.e. genes. The traits of an organism depend on genes, but their expression depends not only on genes but also on many other factors, including whether a gene, controlling the trait, expresses, specific cells in which it expresses and specially the mode by which the gene and its product interact with the environment. A special aspect within the application of biotechnology occurs as an interaction of a foreign gene with a genome of an integrated organism. Also application of biotechnology provides transfer of one or several favorable genes from any evolutionary category into other category of an organism and in such a way it is possible to develop genetically modified organisms (GMO) having expressed desired, target traits. A survey of the application of biotechnology in the world and our country is presented in this paper.

Genital human papillomavirus infection in women who have sex with women: A review

Sexual transmission of human papillomavirus between women has been postulated on the basis of reports of abnormal Papanicolaou smears in women who reported no prior sex with men and by studies using amplified deoxyribonucleic acid technology for human papillomavirus detection. To review the current knowledge of the epidemiology of human papillomavirus and the Papanicolaou smear screening practices among women who have sex with women, studies were identified from a search of the MEDLINE database from January 1980–June 1999. Several factors, including prior or concurrent sex with men and sexual behaviors between women, validate the possibility of human papillomavirus infection among women who have sex with women, and data support that human papillomavirus transmission also occurs. Limited data indicate that the frequency of routine Papanicolaou smear screening among women who have sex with women may be suboptimal relative to heterosexual women. Education of women who have sex with women and the providers of their health care should counter any assumptions that sex between women confers no risk of human papillomavirus transmission. Women who have sex with women should receive Papanicolaou smear screening in accord with current guidelines. (Am J Obstet Gynecol 2000;183:770-4.)