Amount Of Deoxyribonucleic Acid Research Articles

Vacunas de ADN para peces de vivero

Deoxyribonucleic acid (DNA) vaccination is based on the administration of the gene encoding the vaccine antigen, rather than the antigen itself. Subsequent expression of the antigen by cells in the vaccinated hosts triggers the host immune system. Among the many experimental DNA vaccines tested in various animal species as well as in humans, the vaccines against rhabdovirus diseases in fish have given some of the most promising results. A single intramuscular (IM) injection of microgram amounts of DNA induces rapid and long-lasting protection in farmed salmonids against economically important viruses such as infectious haematopoietic necrosis virus (IHNV) and viral haemorrhagic septicaemia virus (VHSV). DNA vaccines against other types of fish pathogens, however, have so far had limited success. The most efficient delivery route at present is IM injection, and suitable delivery strategies for mass vaccination of small fish have yet to be developed. In terms of safety, no adverse effects in the vaccinated fish have been observed to date. As DNA vaccination is a relatively new technology, various theoretical and long-term safety issues related to the environment and the consumer remain to be fully addressed, although inherently the risks should not be any greater than with the commercial fish vaccines that are currently used. Present classification systems lack clarity in distinguishing DNA-vaccinated animals from genetically modified organisms (GMOs), which could raise issues in terms of licensing and public acceptance of the technology. The potential benefits of DNA vaccines for farmed fish include improved animal welfare, reduced environmental impacts of aquaculture activities, increased food quality and quantity, and more sustainable production. Testing under commercial production conditions has recently been initiated in Canada and Denmark.

Properties of Four Biological Flocs as Related to Settling

The influence of four industrial wastewater types (organic chemical, dye, leather, and winery industries) on the exopolymeric substances (EPSs) constituents [protein, polysaccharide, and deoxyribonucleic acid (DNA)] and physicochemical properties of flocs (contact angle, surface charge, and bound water) was determined. Four laboratory scale activated sludge systems were used; they were fed with real wastewaters and were operated continuously under steady-state conditions. The EPS analysis showed that between 70 and 80% of the extracellular organic material could be attributed to protein. The proteins in the bound form were quantitatively greater than the soluble protein form in winery industry floc EPSs. The soluble protein ratios were higher than bound protein ratios in organic chemical, dye, and leather industries flocs. Lower amounts of protein and high DNA content were found in the EPS flocs grown on wastewaters containing more complex substrates (organic chemical, leather, and dye). Changing the wastewater from chemical, leather, and dye to that of winery industry resulted in an increase in protein and a decrease in DNA level of floc EPSs. The sludge surface of winery industry flocs were less hydrophobic (small contact angle) and more highly negatively charged compared to chemical, dye, and leather industry flocs. A higher sludge volume index (SVI), an indication of poorer settleability, was associated with both small amounts of EPS and protein and a high amount of DNA. Both high hydrophilic and negatively charged surfaces corresponded to lower levels of SVI and good settling properties. The results of this study demonstrated that wastewater type influenced the EPS composition and physicochemical properties of sludge. The surface properties (surface charge, contact angle, and bound water) and composition of EPS, apart from the carbohydrate content, governed the settleability of sludge and were important in controlling the SVI.

Effects of Processing Techniques on the Forensic DNA Analysis of Human Skeletal Remains

Human remains processed by forensic anthropologists may potentially be used for genetic analysis. Therefore, the condition of the deoxyribonucleic acid (DNA) in processed remains may become an issue for future analysis. Processing techniques employed by anthropologists are highly variable and scanning electron microscopy reveals significant alterations to the bone surface depending upon the technique used. Such damage to the bone indicates differences may exist in quality and quantity of DNA extracted. This study assessed how five processing procedures used by major forensic anthropology laboratories around the country affects the amounts of DNA extracted from human rib bones and the subsequent DNA analysis. The DNA was analyzed using the short tandem repeat (STR) locus CSF1PO and amelogenin. The findings indicate processing procedures used by forensic anthropologists do not adversely affect DNA analysis but prolonged exposure to heat during processing may decrease the yield of information from the DNA.

790 Identification of Hypermethylated Tumor-specific Deoxyribonucleic Acid in Plasma of Patients with Glioma

INTRODUCTION: Although patients without malignancy have <100 ng/ml free deoxyribonucleic acid (DNA) in plasma, patients with malignancy demonstrate substantial quantities of tumor-specific DNA in their plasma. Measurements of this DNA are being studied to develop plasma markers to correlate with tumor burden. This approach has not been explored in gliomas. METHODS: Venous blood (30 ml) was collected before craniotomy from 10 patients with presumed glioma. After surgery, DNA was extracted and quantified from intracranial tumor and plasma samples. The methylation status of p16, p73, RAR&#61538, and MGMT gene promoters was assayed with methylation-specific polymerase chain reaction (MSP). The presence of tumor-specific DNA in the plasma was defined as identification of the same methylated promoter (MP) in both plasma and tumor. RESULTS: Pathological diagnoses were glioblastoma (n = 6), anaplastic astrocytoma (n = 2), anaplastic oligoastrocytoma (n = 1), and oligodendroglioma (n = 1). Total DNA concentration in plasma was grossly elevated (mean, 6503 ng/ml; standard error of the mean, 1400 ng/ml). Tumor specimens revealed methylation of at least one promoter in 9 of 10 patients (90%). Of the 9 patients with MP, 6 (67%) had methylation of at least one of the same promoters in the plasma DNA. Five of these had one MP identified in the plasma, and 1 had two MPs. Overall, glioma-specific methylated DNA was present in plasma of 6 of 10 patients (60%). Tumors with no plasma MP were two glioblastoma, one anaplastic astrocytoma, and one oligodendroglioma. No positive markers were found in the plasma that were not also found in the intracranial tumor. CONCLUSION: Gliomas shed large amounts of DNA into the blood. Using MSP, we found that tumor-specific DNA is present in plasma of glioma patients. This specific as promoter methylation is not found in normal tissue. Isolation of tumor-specific plasma DNA in these patients represents the first step to developing a quantitative glioma plasma biomarker that could be used to monitor tumor status.

Low-volume jet injection for efficient nonviral in vivo gene transfer.

The transfer of naked deoxyribonucleic acid (DNA) represents an alternative to viral and liposomal gene transfer technologies for gene therapy applications. Various procedures are employed to deliver naked DNA into the desired cells or tissues in vitro and in vivo, such as by simple needle injection, particle bombardment, in vivo electroporation or jet injection. Among the various nonviral gene delivery technologies jet injection is gaining increasing acceptance because it allows gene transfer into different tissues with deeper penetration of the applied naked DNA. The versatile hand-held Swiss jet injector uses pressurized air to force small volumes of 3 to 10 microL of naked DNA into targeted tissues. The beta-galactosidase (LacZ) reporter gene construct and tumor necrosis factor alpha gene-expressing vectors were successfully jet injected at a pressure of 3.0 bar into xenotransplanted human tumor models of colon carcinoma. Qualitative and quantitative expression analysis of jet injected tumor tissues revealed the efficient expression of these genes in the tumors. Using this Swiss jet-injector prototype repeated jet injections of low volumes (3-10 microL) into one target tissue can easily be performed. The key parameters of in vivo jet injection such as jet injection volume, pressure, jet penetration into the tumor tissue, DNA stability have been defined for optimized nonviral gene therapy. These studies demonstrate the applicability of the jet injection technology for the efficient and simultaneous in vivo gene transfer of two different plasmid DNAs into tumors. It can be employed for nonviral gene therapy of cancer using minimal amounts of naked DNA.

The comet assay for DNA damage and repair: principles, applications, and limitations.

The comet assay (single-cell gel electrophoresis) is a simple method for measuring deoxyribonucleic acid (DNA) strand breaks in eukaryotic cells. Cells embedded in agarose on a microscope slide are lysed with detergent and high salt to form nucleoids containing supercoiled loops of DNA linked to the nuclear matrix. Electrophoresis at high pH results in structures resembling comets, observed by fluorescence microscopy; the intensity of the comet tail relative to the head reflects the number of DNA breaks. The likely basis for this is that loops containing a break lose their supercoiling and become free to extend toward the anode. The assay has applications in testing novel chemicals for genotoxicity, monitoring environmental contamination with genotoxins, human biomonitoring and molecular epidemiology, and fundamental research in DNA damage and repair. The sensitivity and specificity of the assay are greatly enhanced if the nucleoids are incubated with bacterial repair endonucleases that recognize specific kinds of damage in the DNA and convert lesions to DNA breaks, increasing the amount of DNA in the comet tail. DNA repair can be monitored by incubating cells after treatment with damaging agent and measuring the damage remaining at intervals. Alternatively, the repair activity in a cell extract can be measured by incubating it with nucleoids containing specific damage.

Comparing Three DNA Extraction Procedures for Cost, Efficiency, and DNA Yield

An efficient deoxyribonucleic acid (DNA) extraction procedure that yields large quantities of DNA would provide adequate DNA for a large number of different analytical procedures. This study was conducted to compare three DNA extraction procedures for cost, time efficiency, and DNA content while extracting DNA from Kentucky bluegrass (Poa pratensis L.). Three students at the Univ. of Illinois with varying levels of DNA extraction experience conducted DNA extractions using Plant DNeasy™ Mini Kits, Plant DNAzol® Reagent, and a PEX/CTAB buffer. Costs varied significantly with cost (US$) per DNA sample of $3.04 for the DNeasy™ method, $0.99 for the DNAzol® method, and $0.39 for the PEX/CTAB extraction. The DNAzol® method was the fastest; although extracting 2.8 ng less DNA than the DNeasy™ method, it did not require the use of hazardous organic solvents, and random amplified polymorphic DNA (RAPD) markers were satisfactory for DNA fingerprinting of Kentucky bluegrass cultivars. The PEX/CTAB method, which did not include a tissue homogenization step, did not have reproducible banding patterns due to miniscule and inconsistent quantities of DNA extracted, or possibly due to inadequate purification. The investigator with the least DNA extraction experience was the slowest, while extracting 75% more DNA. All three methods are easily adapted to laboratories having personnel with different levels of experience. The DNAzol® Reagent method should save time and money, with reproducible results when many individual plant samples need to be identified. Chemical names used: potassium ethyl xanthogenate (PEX); cetyltrimethyl ammonium bromide (CTAB)

Typing of DNA HLA-DQα Alleles Extracted from Human Nail Material Using Polymerase Chain Reaction

The deoxyribonucleic acid (DNA) typing of human Leukocyte Antigen (HLA) DQ alpha from human fingernails is described. HLA-DQ alpha genotypes can be accurately determined from clipped fingernails. We have typed 26 nails accurately, while one did not give any type since that one sample did not amplify due to the low quantity of DNA. The cut off limit for the digested material to be amplified is approximately 9 mgs of nail material.

Outer Membrane-associated Deoxyribonuclease Activity of Porphyromonas gingivalis

Extracellular outer membrane vesicles which are produced by Gram-negative bacteria may enclose deoxyribonucleic acid (DNA). While characterizing vesicles of Porphyromonas gingivalis, it was found that they do not contain detectable amount of DNA. It was also shown that the presence of deoxyribonuclease activity on whole cells and vesicles can degrade plasmidic and linear DNA. Deoxyribonuclease activity was also demonstrated in several other Gram-negative oral bacterial species. The nuclease activity of P. gingivalis was further characterized. When deoxyribonuclease activity was analyzed by zymography, only one active band was detected under the conditions tested. This nuclease enzyme showed a molecular weight of approximately 50 kDa. The activity was inhibited by 5 mM ZnCl 2 or 100 mM EDTA whereas Mg 2+ or Ca 2+ ions were not required for activity. Activity was totally destroyed by treatment at 70°C for 15 min. Although the enzyme may participate in virulence or provide nucleic acid precursors for bacterial growth, its exact role is still unknown.

Polymerase Chain Reaction for Educational Settings

Polymerase chain reaction (PCR) is considered one of the most significant DNA (deoxyribonucleic acid) technologies to be developed. A method of amplifying tiny amounts of DNA, PCR1 uses enzymes and raw materials to copy part of a genome for subsequent sequencing or other analyses. With this research technique, a few micrograms of DNA can be amplified millions or billions of times in two to three hours. This allows researchers to do DNA analyses from any organism, even when very little DNA is available. Kerry Mullis conceived of this technique in 1985 while working for Cetus Corporation and he recently received a Nobel Prize for his visionary work (Mullis et al. 1986). PCR amplification is not limited to cutting-edge university or industry laboratories, but can be completed in educational settings, such as high school or college biology labs. Including PCR in lab exercises can promote student understanding of DNA molecule structure, enzyme function, complementary base pairing, and electrophoresis. Using PCR technology, instructors can increase the scope and sophistication of biology lab sessions. A review of DNA structure and composition will help students better understand how PCR amplification works. The DNA molecule has a ladder-like shape, with four deoxynucleotides (adenine, thymine, guanine and cytosine, which are abbreviated A,T,G,C). These comprise the rungs of the ladder (see Figure 1). Deoxynucleotides (also called bases) bind to one another in a specific way between the rungs: A with T, and G with C. These base pair arrangements form the genome of an organism. About 6 billion base pairs comprise the 24 chromosomes that make up the human genome (Campbell 1993).

Validation Studies on the Forensic Analysis of Restriction Fragment Length Polymorphism (RFLP) on LE Agarose Gels Without Ethidium Bromide: Effects of Contaminants, Sunlight, and the Electrophoresis of Varying Quantities of Deoxyribonucleic Acid (DNA)

This study was designed to analyze the effects of sunlight, various contaminants (those found typically in forensic samples) and the electrophoresis of varying quantities of DNA on the restriction fragment length polymorphism (RFLP) patterns produced from DNA isolated from blood and semen stains. The DNA RFLP patterns were obtained following Hae III restriction enzyme digestion, low electroendosmotic (LE) agarose gel electrophoresis (in the absence of ethidium bromide), Southern transfer, hybridization with DNA probes detecting highly polymorphic variable number of tandem repeats (VNTRs) and autoradiography. Computer assisted image analyses were used to detect variations in RFLP band sizes in relation to control samples. Comparisons between the samples were made for the presence of high molecular weight DNA, the ability to achieve a complete restriction digestion, and the RFLP fragment sizes obtained. The results demonstrate that high molecular weight DNA can be obtained when blood and semen stains are subjected to environmental and contaminating factors. The RFLP allele sizes were not significantly affected by environmental conditions, contamination factors or by loading varying amounts of DNA. This study serves to further document the reliability and validity of DNA typing for forensic applications.

Isolated cerebellar lymphomatoid granulomatosis progressing to malignant lymphoma

A 60-year-old man presented with progressive and unique neurological symptoms. Investigations identified an isolated cerebellar lesion. This lesion fulfilled the histological criteria for lymphomatoid granulomatosis, and in situ hybridization and deoxyribonucleic acid (DNA) dot blot techniques revealed significant amounts of Epstein-Barr virus DNA within the tumor cells. The patient underwent cranial radiation therapy, and 16 months after the initial presentation the lesion evolved into a malignant lymphoma. He subsequently died secondary to subdural empyema, bacterial meningitis, and bronchopneumonia. The unique clinical and etiological aspects of this case are addressed.

Purification of Forensic Specimens for the Polymerase Chain Reaction (PCR) Analysis

Purification methods of deoxyribonucleic acid (DNA) from degraded and contaminated forensic samples were investigated for polymerase chain reaction (PCR) analysis. DNA extracted from putrefied tissue or bloodstains sometimes contained the copurified contaminant, that was identified as the porphyrin compound (hematin). When contaminated but less degraded DNA was analyzed by PCR, it was necessary to eliminate the impurity by anion exchange column chromatography or chelating resin preparation, and ultrafiltration using Centricon microconcentrators. When highly degraded DNA was analyzed, trace amounts of high molecular weight DNA was recovered by electroelution method, and then further purified by both column chromatography and ultrafiltration. From thus purified samples, the amelogenin gene for sex determination could be amplified by dual PCR technique.

Quantitative Estimation of Tissue Prostate Specific Antigen, Deoxyribonucleic Acid Ploidy and Cytological Grade in Fine Needle Aspiration Biopsies for Prognosis of Hormonally Treated Prostatic Carcinoma

The prognostic value of deoxyribonucleic acid (DNA) flow cytometry, cytological grading and the direct assay of prostate specific antigen (PSA) in the material of fine needle aspirates was studied in 67 consecutive patients with newly detected prostatic carcinoma. All patients were hormonally treated (castration in 27 and luteinizing hormone-releasing hormone agonist or parenteral estrogens in 40). The patients were followed for a minimum of 2 years. PSA was analyzed in the biopsy material by a direct radioimmunoassay and related to the total amount of DNA. In parallel biopsies DNA ploidy using flow cytometry and cytological grade were established. Patients with a geometric mean value of ≧0.12μg. PSA/μg. DNA had a progression rate of 7%, compared to 59% for those with <0.12 μg. PSA/μg. DNA. In Cox multivariate analysis cytology and tissue PSA content were the most important factors in expressing the difference for interval to progression in hormonally treated patients.

Induction of transformational changes in normal endothelial cells by cultured human astrocytoma cells

Endothelial cell proliferation is a significant biological feature of malignant astrocytomas. The ability of the cells of these tumors to elaborate mitogenic angiogenesis factors has been well documented. However, less is known about the transformational effects that neoplastic astrocytes may have on the endothelial cells within malignant astrocytomas. In this study, the hypothesis that humoral factors elaborated by cells derived from malignant astrocytomas induce transformational changes in normal endothelial cells in vitro is investigated. Conditioned medium (CM) was prepared from exponentially growing cultures of a human glioblastoma cell line (UW18) and from two rat brain-tumor cell lines: an anaplastic astrocytoma (R175A) and a glioblastoma with sarcomatous elements (9L). Subconfluent target bovine aortic arch endothelial cells (BAEC's) were exposed for 48 hours to varying concentrations of CM prepared from each of these tumors, and then evaluated for transformational changes. Different molecular weight (MW) fractions of UW18 CM were prepared by molecular ultrafiltration, and each fraction was tested for transforming activity. Transformation endpoints included changes in cellular deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) content and distribution (measured by differential flow cytometry) and changes in de novo DNA synthesis determined by 3H-thymidine incorporation. Significant changes in the amount and distribution of DNA and RNA were observed in the BAEC's treated with UW18 CM compared to untreated BAEC's. At 10% concentrations of UW18 CM, changes in the RNA profile of target BAEC's were evident, and at 30% concentrations of UW18 CM, an irregular bimodal distribution was well established. Patterns of DNA were also altered in a concentration-dependent manner, with significant aneuploidy developing at UW18 CM concentrations of 20%. The DNA synthesis in BAEC's increased with increasing CM concentrations, up to a maximum of about 250% of control values at 30% concentrations of UW18 CM. The transformational changes induced after exposure of BAEC's to CM prepared from R175A and 9L were significantly less than those observed with UW18 CM. Molecular ultrafiltration was used to prepare UW18 CM fractions with MW cutoffs of less than 10 kD, 10 to 30 kD, and greater than 30 kD. Transformational activity was significant only in CM's with an MW of 10 to 30 kD. It is concluded that the UW18 human glioblastoma cell line elaborates a soluble factor, or group of factors, with an MW in the 10- to 30-kD range, capable of inducing transformational alterations in target normal endothelial cells, and that such transformation may account for some of the abnormal endothelial cell changes associated with malignant astrocytomas.

Sensitive and Specific Quantification of Human Genomic Deoxyribonucleic Acid (DNA) in Forensic Science Specimens: Casework Examples

We describe the forensic science application of a method for quantification of human genomic deoxyribonucleic acid (DNA). The two cases cited in this report involve DNA samples extracted from skin tissue and bloodstained clothing recovered from different crime scenes. High-molecular-weight DNA was recovered from both specimens, and the concentrations of these DNAs were estimated to be approximately 0.5 microgram/microL by ethidium bromide/agarose gel electrophoresis. Using the human-specific DNA probe p17H8 (locus D17Z1) to quantify the amount of human genomic DNA in these samples, it is shown that less than 1% of the DNA isolated from the skin tissue is of human origin and that the DNA isolated from the bloodstained clothing is effectively devoid of human DNA sequences. These case examples illustrate the need to quantify not only the total amount of DNA recovered from forensic casework material, but also the proportion of the DNA that is of human origin.

The polymerase chain reaction and infectious diseases: hopes and realities

Introduction It is not often that a technique has as immediate and dramatic an impact on science as the polymerase chain reaction (PCR) has had on molecular biology. The ability to amplify large quantities of a defined region of deoxyribonucleic acid (DNA) rapidly and specifically from a few starting copies has led to a reassessment of many old procedures, and to a host of new applications (EHRLICH, 1989; INNIS et al., 1990). Many of these are methodological, making it simpler to clone and manipulate genes. However, PCR also promises to revolutionize the diagnosis of disease. In the case of genetic disease, its claims are overwhehning, since alternatives are generally either lacking altogether, or are inadequate. However, regarding its use with mfectious diseases, particularly in developing countries, sceptics are rather more numerous. In this article I will discuss the potential strengths and weaknesses of PCR in this field. PCR is based on (i) the ability of short oligonucleotides (e.g. 15-25 bases) to hybridize rapidly and specifically to complementary DNA sequences, even in the presence of large amounts of non-complementary DNA, and (ii) the requirement that DNA polymerases have for a primer bound to a template strand in order to synthesize DNA. This means that if a suitable oligonucleotide primer is used, DNA synthesis can be specifically initiated at any point in a genome in vitro. By using 2 primers, which bind different strands of the target DNA a few hundred nucleotides apart, and allowing DNA synthesis to take place, 2 new strands of DNA will be synthesized, each of which will, crucially, include the sequences complementary to the other oligonucleotide primer. Following denaturation and reannealing steps, all new strands will themselves act as substrates for a further round of DNA synthesis, and the repetition of this cycle many times leads to an exponential increase in copies of the specific DNA target. The 3 elements of the cycle-denaturation, annealing and DNA synthesis-can all be controlled simply by temperature shifts. After the first 2 cycles, virtually all the DNA synthesized will be of a specific length, flanked by the 2 priming sequences, and the most common form of detection used is the visualization by fluorescence under ultraviolet light of a small DNA fragment of predicted size after agarose gel electrophoresis in the presence of ethidium bromide. The technical advances which have made PCR a routine tool are (i) the use of a thermostable DNA polymerase which can withstand the high temperatures required for DNA denaturation (SAIKI et al., 1988), (ii) the production of microprocessor-controlled programmable heating blocks, and (iii) the ready availability of synthetic oligonucleotides. For some years, DNA probes have promised much as diagnostic tools, but have delivered little mainly because of a lack of sensitivity. PCR has removed this barrier, although problems still remain.

Growth and Differentiation of the Gubernaculum Testis During Testicular Descent in the Pig: Changes in the Extracellular Matrix, Dna Content, and Hyaluronidase, β-Glucuronidase, and β-N-Acetylglucosaminidase Activities

The gubernaculum testis is a loose connective tissue organ that plays an essential mechanical role in testicular descent. In the pig, the first phase of descent (transabdominal migration) is brought about by growth of the gubernaculum through the inguinal canal into the scrotum and simultaneous somatic growth of the fetus. During the second phase the gubernaculum condenses, thus allowing the testis to descend into the scrotum.The nature of gubernaculum development (growth and differentiation) was investigated with respect to cell proliferation, extracellular matrix (ECM) composition, and acid hydrolases. Deoxyribonucleic acid (DNA) was used as a measure of cell number and hydroxyproline (HYP) was an estimate of interstitial collagen.The first phase of gubernaculum development was characterized by rapid cell proliferation and concomitant synthesis of sulphated glycosaminoglycans (S-GAG), hyaluronic acid (HA) and collagen. During the second phase cell proliferation ceased and DNA concentration increased. The amount of S-GAG remained closely related to the amount of DNA while HYP increased further. However, HA decreased during the second phase and thus HA metabolism seems to play a crucial role in biphasic development of the gubernaculum. The activities of the enzymes that are needed for biodegradation of HA (hyaluronidase, β-glucuronidase and β-N-acetylglucosaminidase) were measured in gubernaculum homogenate from animals during the first and second phase of testicular descent. These enzymes were detectable in gubernaculum and rose during the second phase of testicular descent.It was concluded that a very distinct dichotomy in the nature of gubernaculum development during the first and second phase could be discerned with respect to cell proliferation rate and ECM synthesis and degradation. These observations provide useful tools for future in vivo and in vitro investigations into the process and regulation of testicular descent. (J. Urol, 142: 837–845, 1989)

System automates DNA amplification

A system that makes microgram quantities of deoxyribonucleic acid (DNA) in a few hours by amplification of nanogram amounts has been introduced by Perkin-Elmer Cetus Instruments, Norwalk, Conn. The...

Quantitative DNA analysis of low grade cervical intraepithelial neoplasia and human papillomavirus infection by static and flow cytometry.

Quantitative deoxyribonucleic acid (DNA) analysis of cervical biopsy specimens from 26 women with cytological, colposcopic, and histological evidence of mild cervical atypia consistent with cervical intraepithelial neoplasia grade I, reactive atypia, or human papillomavirus infection alone or in combination was performed in a comparative evaluation of Feulgen microspectrophotometry, the fast interval processor image analysis system, and flow cytometry. The fast interval processor image analysis system showed a distinct advantage over the other methods, being faster and allowing the operator to see the cells that were selected for measurement. The three methods of measurement together showed that the DNA content of at least 2% of the cells measured exceeded 5C (C being the haploid amount of DNA in a normal cell and 2C representing the diploid complement of a normal cell) in all cases of cervical intraepithelial neoplasia grade I and reactive atypia and in 87% of those reported as showing human papillomavirus infection alone. In contrast, the DNA content of cervical biopsy specimens from the transformation zone of 11 normal controls did not exceed 4C. This study shows the value of using a DNA threshold--that is, the "5C exceeding rate"--to distinguish between normal and neoplastic appearances of the cervix. These results support the view that cervical infection by human papillomavirus is a true precursor of neoplasia.