Lesion formation and antibody response induced by papillomatous digital dermatitis-associated spirochetes in a murine abscess model

Papillomatous digital dermatitis (PDD), also known as hairy heel wart, is a growing cause of lameness of cows in the U.S. dairy industry. Farms with PDD-afflicted cows experience economic loss due to treatment costs, decreased milk production, lower reproductive efficiency, and premature culling. While the exact cause of PDD is unknown, lesion development is associated with the presence of anaerobic spirochetes. This study was undertaken to investigate the virulence and antigenic relatedness of four previously isolated Treponema phagedenis-like spirochetes (1A, 3A, 4A, and 5B) by using a mouse abscess model with subcutaneous inoculation of 10(9), 10(10), and 10(11) spirochetes. Each of the PDD isolates induced abscess formation, with strain 3A causing cutaneous ulceration. Lesion development and antibody responses were dose dependent and differed significantly from those seen with the nonpathogenic human T. phagedenis strain. Strains 3A, 4A, and 5B showed two-way cross-reactivity with each other and a one-way cross-reaction with T. phagedenis. Strain 5B showed one-way cross-reactivity with 1A. None of the isolates showed cross-reactivity with T. denticola. In addition, distinct differences in immunoglobulin G subclass elicitation occurred between the PDD strains and T. phagedenis. From these data, we conclude that spirochetes isolated from PDD lesions have differential virulence and antigenic traits in vivo. Continuing investigation of these properties is important for the elucidation of virulence mechanisms and antigenic targets for vaccine development.

Is Mycoplasma hominis a vaginal pathogen?

OBJECTIVE

To evaluate the role of Mycoplasma hominis as a vaginal pathogen.

DESIGN

Prospective study comprising detailed history, clinical examination, sexually transmitted infection (STI) and bacterial vaginosis screen, vaginal swabs for mycoplasmas and other organisms, follow up of bacterial vaginosis patients, and analysis of results using SPSS package.

SETTING

Genitourinary medicine clinic, Royal Liverpool University Hospital.

PARTICIPANTS

1200 consecutive unselected new patients who had not received an antimicrobial in the preceding 3 weeks, and seen by the principal author, between June 1987 and May 1995.

MAIN OUTCOME MEASURES

Relation of M. hominis isolation rate and colony count to: (a) vaginal symptoms and with the number of polymorphonuclear leucocytes (PMN) per high power field in the Gram stained vaginal smear in patients with a single condition--that is, candidiasis, bacterial vaginosis, genital warts, chlamydial infection, or trichomoniasis, as well as in patients with no genital infection; (b) epidemiological characteristics of bacterial vaginosis.

RESULTS

1568 diagnoses were made (the numbers with single condition are in parenthesis). These included 291 (154) cases of candidiasis, 208 (123) cases of bacterial vaginosis, 240 (93) with genital warts, 140 (42) chlamydial infections, 54 (29) cases of trichomoniasis, and 249 women with no condition requiring treatment. M. hominis was found in the vagina in 341 women, but its isolation rates and colony counts among those with symptoms were not significantly different from those without symptoms in the single condition categories. There was no association between M. hominis and the number of PMN in Gram stained vaginal smears whether M. hominis was present alone or in combination with another single condition. M. hominis had no impact on epidemiological characteristics of bacterial vaginosis.

CONCLUSION

This study shows no evidence that M. hominis is a vaginal pathogen in adults.

Novel HPV types present in oral papillomatous lesions from patients with HIV infection

Patients infected with the human immunodeficiency virus (HIV) often develop multiple papillomatous lesions of the oral cavity. In the present study, a total of 67 biopsies from benign oral lesions were analyzed for the presence of human papillomavirus (HPV) DNA using Southern-blot hybridization in combination with a polymerase chain reaction designed to detect all known HPV types, as well as unidentified types. These samples, collected at random from a high-risk population, were subsequently divided into 57 biopsies originating from patients with confirmed HIV infection and 10 biopsies from patients with unknown HIV status. Each sample was amplified with 7 different combinations of degenerate primers. All amplified products were sequenced. HPV DNA sequences were detected in 67% (45/67) of the samples. HPV 7 (19%) and HPV 32 (28%) were the predominant HPV types. HPV 32 was present in 2/4 fibromas tested. Two new HPV types, HPV 72 and HPV 73, were identified in oral warts with atypia. The complete genomes of these viruses were cloned and sequenced. Other HPV types detected were HPV 2a, HPV 6b, HPV 13, HPV 16, HPV 18, HPV 55, HPV 59 and HPV 69.

Electronmicroscopic diagnosis of human papilloma virus in verruca plantaris

The purpose of this study was to identify the human papilloma virus in verruca plantaris by transmission electron microscopy and study the cellular effect of human papilloma virus at both the transmission electron microscopy and light histochemistry level. The authors discuss the cellular pathology in relation to early studies and keratin disorders. Features identified by transmission electron microscopy are consistent with characteristics of human papilloma virus-1.

Use of HPV 1 capsids produced by recombinant vaccinia viruses in an ELISA to detect serum antibodies in people with foot warts

A sandwich ELISA was developed to detect HPV antibodies using HPV 1 capsids that were purified from recombinant vaccinia virus-infected cells and a monoclonal antibody to the HPV 1 L1 protein. Sera from 91 college-aged women who had been previously screened for HPV 1 antibodies by immune precipitation of capsid proteins were tested by ELISA. A cutoff point was established independently of other criteria based on the assumption that the ELISA values came from a mixture of two Normal distributions representing seropositive and seronegative individuals. It was found that the data fit this model best when the natural log of the ELISA (+0.5 to make all of the values positive) was used. Positive sera were shown to react with a conformational epitope(s) on the L1 protein. In the population reporting foot warts, 16 of 18 (89%) had ELISA values above the cutoff. This compared to 38 of 73 (53%) positives in the population reporting no history of foot warts. The odds ratio for the association of the ELISA reactivity with foot warts was 7.23 (95% CI 1.53, 69.4; P < 0.01). There was no significant association between the ELISA reactivity and wart infections reported at other sites. The average of the log ELISA values for individuals never reporting foot warts was -0.223 (SD 0.468), whereas the average value for individuals reporting foot warts within 10 years was 0.191 (SD 0.450) (P = 0.001). There was a negative correlation between the magnitude of ELISA reactivity and the time elapsed since the last appearance of foot warts. This apparent loss of seroreactivity over time may indicate that HPV 1 is usually eliminated from the host after infection or that inadequate levels of HPV 1 capsid antigen are produced during latent foot warts to maintain antibody levels.

Double infection with human papillomavirus 1 and human papillomavirus 63 in single cells of a lesion displaying only an human papillomavirus 63-induced cytopathogenic effect

BACKGROUND

Specific histologic features are associated with the presence of certain human papillomaviruses (HPV) in verrucous lesions of the skin. HPV 1 is known to be associated with eosinophilic keratohyalin-like intracytoplasmic inclusion bodies, granular in appearance, whereas the recently described HPV 63 seems to induce inclusion bodies displaying a filamentous structure. Although an infection by two distinct HPV types within a single cell has not been previously reported, we have recently treated a plantar punctate keratotic wart in which only the histologic features seen in an HPV 63-induced lesion were seen, in spite of the detection of double infection of both HPV 1 and HPV 63 DNAs, thus posing the question as to the role of the HPV 1 present in the lesion.

EXPERIMENTAL DESIGN

To localize the genomes of these two viruses within the lesion, double fluorescence in situ hybridization was performed using biotin-labeled HPV 63 DNA and digoxigenin-labeled HPV 1 DNA. The distribution of the genomes of these two viruses was examined in comparison with the histologic features in the lesion. The copy numbers of HPV 63 and HPV 1 were compared on agarose gel electrophoresis, stained with ethidium-bromide.

RESULTS

We demonstrated the presence of the DNA of both HPV 1 and HPV 63 within the same nucleus of a plantar wart. In spite of the double infection of these two viruses in a cell and more or less equal copy numbers of the viruses, the cytopathogenic effect of only HPV 63 was seen in the cells.

CONCLUSIONS

This is the first report of double infection of two different types of HPV within the same nucleus. Our findings suggest the possible interference that two HPV types could have on each other in inducing the HPV type specific cytopathogenic effects.

Characterization and analysis of human papillomaviruses of skin warts

We analysed human papillomavirus (HPV) infections in 61 tissue specimens of skin warts of Taiwanese patients by DNA hybridization. The prevalence of HPV infection was 69% by Southern blot hybridization. The typing of HPVs was performed by dot blot hybridization under highly stringent conditions with each probe separately. The prevalence of HPV-1, 2/3, 4, 5, 8, 11, 16 and 18 in skin warts was 13, 7, 16, 2, 0, 5, 2 and 8%, respectively. Chi-squared analysis revealed that there was a correlation between HPV type and copy number. Most HPV-4-induced warts were verruca vulgaris. HPV-1 DNA was detected in verruca plantaris and verruca vulgaris. No specific histopathological features were found to be indicative of the presence or absence of HPV, or of the various types of HPV infection.

Human papillomavirus and cutaneous warts in meat handlers

The association of papillomavirus and hand warts in meat handlers was examined. Human papillomavirus (HPV) DNA was found in 23 (88%) of 26 cutaneous warts, with HPV 7 (27%) and a yet unidentified HPV (HPV X) (42%) being the predominant types. HPV 2 was found in two (7.5%) patients, and HPV 4 was found in three (11.5%) patients. No bovine papillomavirus sequences were detected. In most patients, the warts developed in less than 2 years after they started working with meat. A possible HPV transmission route by protection gloves and professional equipment is suggested.

Detection of human papillomavirus type 2a DNA in verrucae vulgares by electron microscopic in situ hybridization

Electron microscopic in situ hybridization (EMISH) of common warts (verrucae vulgares) of the hands was performed using a biotinylated human papillomavirus type 2a (HPV-2a) DNA probe and immunogold labelling of ultrathin sections of 2% glutaraldehyde-fixed, Lowicryl K4M-embedded tissues. It was first established that the warts contained HPV-2a DNA by light microscopic in situ hybridization. The HPV-2a probe chiefly labelled cells in the horny, granular and upper spinous layers of the epidermis, and labelling decreased towards the basal cell layer. The gold particles were located precisely on the viral particles in the nuclei of granular cells. The lower limit of detection by EMISH was found to be the keratinocytes of the third cellular layer above the basal cells. These keratinocytes showed evidence of a viral cytopathic effect, suggesting that vegetative DNA replication in infected keratinocytes occurs at least as early as this level of the epidermis.

Are viral warts seen more commonly in children with eczema?

BACKGROUND AND DESIGN

We sought to test the hypothesis that warts are seen more commonly in individuals with eczema by analyzing skin examination data from a national birth cohort study of 9263 British children born between March 3 and 9, 1958.

RESULTS

Warts were seen less frequently in those with visible eczema at ages 11 and 16 years (relative risk, 0.60; 95% confidence intervals, 0.37 to 0.95; P = .03). This inverse association persisted after adjustment for potential confounders and was consistent within each age and sex group for children with a history of eczema who did not have visible eczema at the time of examination and for children with asthma/wheezy bronchitis regardless of eczema status. Visible acne or psoriasis was not associated with a decreased prevalence of warts.

CONCLUSIONS

These findings contradict previous suggestions of an increased risk of viral warts in atopic eczema and raise new questions regarding the role of cell-mediated immunity in atopic subjects.

Production and characterization of human proliferative T-cell clones specific for human papillomavirus type 1 E4 protein

Human papillomavirus type 1 (HPV1) virions and E4 protein purified from cutaneous warts were tested in lymphocyte proliferation assays using normal individuals. Both antigens were found to be capable of eliciting good lymphoproliferative responses. Several T-cell clones specific for wart E4 protein were obtained from a donor who had consistently responded very well to E4 in these initial assays. They were maintained in culture by repeated stimulation with antigen and interleukin-2, using an autologous mitomycin-treated lymphoblastoid cell line as a source of antigen-presenting cells. Two of these clones (3F5 and 4A8), which behaved identically, have been studied in more detail. A series of overlapping synthetic peptides covering the entire E1 E4 protein sequence was used to identify a single T-cell epitope which maps to a strongly hydrophilic region spanning amino acid residues 38 to 50. We have also tested the ability of a panel of major histocompatibility complex class II-matched and -mismatched lymphoblastoid cell lines to present this peptide to the T-cell clones in proliferation assays. The study reports that the epitope is restricted through HLA-DQ7 and that it can be recognized by T cells with different T-cell receptor gene rearrangements.

Detection of cutaneous and genital HPV types in clinical samples by PCR using consensus primers

Two sets of consensus PCR primers consisting of a common 3' primer CP-I and two 5'-primers, CP-IIG (primer set A) and CP-IIS (primer set B), in the E1 open reading frame of the human papillomavirus (HPV) genome are presented. These two primer sets enabled the detection of a 188 base pair (bp) fragment of HPV 1, 2, 3, 4, 5, 6b, 7, 8, 9, 10a, 11, 12, 14a, 16, 17, 18, 19, 20, 21, 22, 24, 25, 31, 33, 36, 37, 38, 39 and 46. HPV types 15, 23, 49 and 50 were poorly amplified and HPV type 41 was not amplified. The method is suitable for the detection of HPV DNA sequences in clinical samples of both cervical and cutaneous lesions.

Anogenital warts in children

Fourteen children presenting with anogenital (AG) warts and their close family members were studied; 28.6 and 8.3% of presenting children and other child household members, respectively, had non-genital cutaneous warts; 42.8% of children with AG warts had one or more adult household member with common hand warts. Fifty per cent of all mothers had subclinical cervical papilloma virus (PV) infection; only one male adult had subclinical PV infection of the penis without concurrent AG warts. Of the children with AG warts 42.8% had one or more adult household member with AG warts. Human papilloma virus (HPV) deoxyribonucleic acid (DNA), type 6/11 most frequently, was detected in 38.5% AG wart biopsies from children, and 67% AG wart biopsies from adults. HPV 31/33/35 was detected in 28.5% of cervical preneoplasias and type 6/11 in the one case of subclinical PV infection of the penile shaft. Detection of HPV types 6/11, 16/18, or 31/33/35 in AG warts in children was significantly associated with vertical (from an HPV-infected maternal birth canal during vaginal delivery) or sexual transmission of these warts (Fisher exact probability P = 0.031).

Demonstration of human papillomavirus type 1 DNA in a wart with bowenoid histologic changes

A verrucous lesion on the forearm of a 6-year-old boy was found to be a human papillomavirus type 1 (HPV-1)-induced wart. In addition to typical intracytoplasmic inclusion bodies, the specific cytopathogenic effect of HPV-1 infection, bowenoid changes, were noted on histopathological examination.

Varied clinical morphology of HPV-1-induced warts, depending on anatomical factors

The clinical and histological features of 49 lesions induced by human papillomavirus type 1 (HPV-1) were studied. The majority of cases showed the typical clinical features and location of such lesions. They were usually located on the ventral or lateral surfaces of the hands or feet, and were dome-shaped lesions with a central depression. However, HPV-1-induced lesions located on other body areas displayed different clinical features, such as those of common warts, a digitate wart, and a cutaneous horn. One lesion on a healing burn scar had a herpes-like appearance. As these 49 lesions were induced by the same type of HPV (HPV-1), differences in their clinical features are likely to have been due to host-related factors.

Detection of human papillomavirus-related oral verruca vulgaris among Venezuelans

A sensitive in situ hybridization test under low stringency conditions (LCS) with a set of digoxigenin-labeled human papillomavirus mixed probes (D-L HPV MP) revealed a positive reaction in 8 of 10 cases of oral verruca vulgaris (OVV). Ages ranged from 5 to 37 years with a mean of 14.5 years. 50% of all cases were located intraorally on the hard palate, followed in frequency by the commissures. These preliminary findings provide evidence of the role of HPV in OVV from a sample of the Venezuelan population. We show that in situ hybridization conducted under LSC is useful in HPV detection (regardless of the type) and the digoxigenin-labeling system is a rapid, relatively easy and specific method. In addition, this technique permits the retrospective evaluation of routinely processed material, thus widening the investigative spectrum for HPV.

DNA of bovine papillomavirus type 1 and 2 in equine sarcoids: PCR detection and direct sequencing

Nucleotide sequences of bovine papillomavirus (BPV) DNA amplified by the polymerase chain reaction (PCR) from samples of equine sarcoid skin tumours were determined. All naturally occurring sarcoids (n = 58 tumours from 32 horses and 2 donkeys) contained BPV-DNA. All but 3 of the genome fragments belonged to the BPV type 1 strain (BPV-1); the remaining were BPV type 2. Similar results were obtained with cutaneous bovine papillomas used as controls (n = 20). One of the horses, carrying 2 sarcoids, was particularly interesting; one tumour contained BPV-1 DNA whilst the other sarcoid yielded BPV-2 DNA, suggesting that horses are not immune to super-infection. BPV-DNA was even amplified from the sarcoid samples which had yielded negative results in previous investigations when DNA isolated from the lesions was used in Southern blot hybridization with BPV probes. In addition, there was no detectable BPV-DNA in any equine or bovine tissue examined other than sarcoids or cutaneous bovine papillomas. Biopsies of normal skin surrounding lesions yielded exclusively negative results. The described nucleotide differences represent a natural genomic variation of this BPV type between geographically distant locations. The identical variations recovered from cattle and horses in Switzerland, a finding of great epidemiological interest, strongly suggest that a uniform variant of BPV-1 is one of the etiologic agents of equine sarcoid and bovine papilloma in a given region.

Common warts from immunocompetent patients show the same distribution of human papillomavirus types as common warts from immunocompromised patients

We studied the papillomaviruses (HPV) found in 131 common warts from 111 immunocompetent patients by amplification of viral DNA sequences with the general-primer-mediated polymerase chain reaction (PCR). The virus types were determined by restriction-enzyme cleavage and reverse-blot analysis. Results were confirmed by using the Southern blot technique. Forty patients harboured HPV 2a, 25 individuals showed HPV 2c and 13 yielded HPV 57. Common warts from 16 patients were induced by a variant of HPV 57. HPV 7 was found in four patients. HPV 1 was identified in two patients, and there was evidence for HPV 4 in only one case. One individual yielded an HPV type which was only weakly related to HPV 2. Three patients were infected by more than one HPV type. PCR did not demonstrate HPV-DNA in warts from six individuals. The distribution and variation of HPV types found in the common warts of immunocompetent patients were similar to the findings in immunocompromised patients reported by other authors.

Self-assembly of human papillomavirus type 1 capsids by expression of the L1 protein alone or by coexpression of the L1 and L2 capsid proteins

Vaccinia virus vectors were used to express the major (L1) and minor (L2) capsid proteins of human papillomavirus type 1 (HPV-1) with the vaccinia virus early (p7.5K) or late (pSynth, p11K) promoters. All constructs expressed the appropriate-sized HPV proteins, and both L1 and L2, singly or in combination, localized to the nucleus. Capsids were purified by cesium chloride density gradient centrifugation from nuclei of cells infected with a vaccinia virus-L1 (vac-L1) recombinant or a vac-L1-L2 recombinant but not from vac-L2-infected cells. Electron microscopy showed that the particles were 55 nm in diameter and had icosahedral symmetry. Immunogold-labeled antibodies confirmed the presence of the L1 and L2 proteins in the HPV-1 capsids. Capsids containing L1 alone were fewer and more variable in size and shape than capsids containing the L1 and L2 proteins. The L1-plus-L2 capsids were indistinguishable in appearance from HPV-1 virions obtained from plantar warts. The ability to produce HPV capsids in vitro will be useful in many studies of HPV pathogenicity.

[Molecular aspects of human papillomaviruses and their relation to uterine cervix cancer]

Papillomaviruses (wart viruses) are responsible for the development of benign and malignant epithelial lesions in mammals. More than 60 different types of human papillomaviruses (HPVs) have been isolated to date. Some of them are major candidates as etiologic agents in cervical cancer. DNA from HPV types 16, 18 and 33 is usually found integrated in about 90 percent of genital carcinomas. Integration of the viral DNA into the cellular genome may be an important step towards the development of malignancy. Two early genes of HPVs (E6 y E7) are involved in cellular transformation. Another early gene (E2) participates in gene control by directly binding to conserved DNA motifs in the viral genome. Several protein factors of viral and cellular origin interact with the regulatory region of HPVs and participate in the regulation transcription of oncogenes E6 and E7. Cellular factors, such as immune system and oncogene and anti-oncogene alterations, seem to play an important role in papillomavirus-associated cervical carcinogenesis.

Influence of fixation on human papillomavirus DNA detection in frozen and embedded paraffin lesions by in situ hybridization with biotinylated probes

Series of frozen or paraffin-embedded tissues from various body sites, taken from non-immunosuppressed or immunosuppressed patients with persistent papilloma lesions were examined for the presence of group specific antigen from human papillomavirus (HPV) by indirect immunofluorescence or HPV DNA by in situ hybridization with biotinylated probes. We have shown that it is possible to detect HPV DNA after fixation of tissues in neutral formalin, Bouin's or Baker's solution. However, the sensitivity was reduced as compared to frozen tissues. The HPV DNA was detected in nuclei of heavily infected epithelial cells such as plantar or hand warts or in dispersed cells containing high copy numbers of HPV DNA from lesions such as squamous cell carcinomas or keratoacanthomas. In premalignant or malignant lesions of both immunosuppressed or non-immunosuppressed patients, HPV DNA was rarely detected after fixation. HPV types commonly described for skin and genital samples were identified in non-immunosuppressed patients, whereas in transplant recipients oncogenic HPV type 16 was identified in benign warts as well as in premalignant or malignant lesions. Positive reactions with several HPV types were more frequent in lesions from grafted patients than from the normal population. Virus antigen was detectable more frequently in frozen sections than in fixed tissues. Our findings indicate that in situ hybridization is an appropriate and rapid technique to study the presence of HPV infection. However, numerous controls are needed to avoid misinterpretations.

Lymphoproliferative responses to human papillomaviruses in patients with cutaneous warts

In vitro lymphoproliferative responses of peripheral blood mononuclear cells (PBMC) from patients with cutaneous warts, caused by infection with human papillomavirus type 1 (HPV-1) or type 2 (HPV-2), were assayed during the course of treatment. Purified HPV-1 and HPV-2 were used as antigens, as well as herpes simplex virus (HSV) and concanavalin A (Con A). All patients had normal percentages of subsets within the PBMC population and normal lymphoproliferative responses to Con A, and those with a clinical history of HSV infections had positive lymphoproliferative responses to HSV. Responses to both HPV antigens were poor. Only 10 of 100 assays of PBMC from 26 patients showed a stimulation index greater than 2. Addition of interleukin 2 made little difference in most cases. No correlation of clinical status of warts, i.e. improving, unchanged or resolved, with lymphoproliferation was found. When the PBMC were depleted of plastic-adherent cells and enriched for T cells, some samples which had not shown a lymphoproliferative response to HPV-1 or HPV-2 became positive; this response was abolished when the adherent cells were re-added. Thus it is possible that the adherent cell population from a proportion of patients contains cells which suppress lymphoproliferation, or that an immunoregulatory network is present so that lymphoproliferation does not take place in vitro without prior activation and cloning of T cells.

Southern blot hybridization and PCR in detection of oral human papillomavirus (HPV) infections in women with genital HPV infections

The presence of human papillomavirus (HPV) in biopsies taken from clinically normal buccal mucosa (n = 212) and clinical lesions (n = 60) was examined by Southern blot hybridization (SBH) using 32P-labelled HPV DNA probes. Furthermore, one hundred formalin-fixed, paraffin-embedded biopsies were analyzed by using polymerase chain reaction (PCR), combined with dot blot hybridization and biotinylated HPV DNA probes. With SBH and PCR, 15.4% and 29.4% of the biopsies, respectively, contained HPV DNA. In clinically normal epithelium, 15.6% and 23.1% of the samples were HPV-positive with SBH and PCR, respectively. The HPV types detected in the genital and oral mucosa of index patients differed in all except two cases. Histology could not be relied on distinguishing HPV DNA positive and HPV DNA negative samples. Hand warts were encountered significantly more frequently in patients with a concomitant oral HPV infection. To conclude, oral HPV infections as detected by SBH and PCR are surprisingly common, but similar to the genital tract, the virus seems to exist in a latent form in the vast majority of cases. The frequent concomitant finding of skin warts and oral HPV infection may suggest some kind of HPV-specific immunosuppression.

Verruciform xanthoma of the ear with coexisting epidermal dysplasia

We report a case of verruciform xanthoma of the ear in a 79-year-old man. The case is unique in that it contained an area of solar keratosis. In situ hybridization using biotin-labeled probe cocktails for human papillomavirus types 6/11, 16/18, and 31/33/35 yielded negative results.

Human papillomavirus DNA detection in primary anogenital warts and cervical low-grade intraepithelial neoplasias in adults by in situ hybridization

In this study, 58 consecutive patients with primary anogenital warts were selected from patients attending a genitourinary clinic. Patients were grouped on the basis of clinical lesion site, i.e. patients with genital warts only, patients with perianal or anal canal warts only, and patients with concurrent perianal and genital warts. Of these patients, 38% of the men (12/31) and 33.3% of the women (9/27) had other anogenital infections, such as nonspecific urethritis (NSU) or nonspecific genital infection, which were the most common. Of the patients who had perianal warts, 37% of the men (7/19) and 25% of the women (4/16) also had warts in the anal canal. Of the women who had anogenital warts, 63% (17/27) had concurrent subclinical low-grade cervical intraepithelial neoplasia (CIN) lesions. Human papilloma virus (HPV) DNA (either 6 or 11, 16 or 18, or 31 or 33 or 35) was detected in 53.3% (40/75) of the anogenital wart biopsy samples, and in 35.2% (6/17) of the low-grade CIN lesions. HPV types 6 or 11 were the most common types in anogenital warts (45.3%); and in CIN lesions HPV types 6 or 11 and 16 or 18 were found with equal frequency (17.6% each). There were no significant differences in HPV types between patients with genital warts and patients with perianal and anal canal warts. Anogenital infection with HPV is multicentric; external anogenital warts and subclinical CIN lesions often exist concurrently. The low prevalence of HPV DNA detected in anogenital warts and CIN biopsy samples may be due to insensitivity of the in situ hybridization technique used in this study.

Human papillomavirus (HPV) types specific of epidermodysplasia verruciformis detected in warts induced by HPV3 or HPV3-related types in immunosuppressed patients

Epidermodysplasia verruciformis (EV) is characterized by an abnormal genetic predisposition to infection with specific types of human papillomavirus (HPV). Specific defects of the cell-mediated immunity and/or of the control of HPV infection in keratinocytes are assumed to be involved in the development of the disease. As a model to test this hypothesis, we have studied the prevalence of EV-specific HPV in skin warts of 56 immunosuppressed patients. All main types of cutaneous HPV (HPV1, 2, 3, 4, 10, and 28) responsible for skin warts in the general population were detected by blot hybridization. EV-specific HPV (HPV5, 20, and 23) were detected in three patients. Four additional patients were found infected with HPV49, first characterized in the course of this study, and found to be related to EV HPV. A most important finding was that HPV5, 20, 23, and 49 were always codetected with HPV3 or the related types HPV10 and 28. None of the specimens showed the typical clinical morphology of EV lesions. In none of these specimens was the specific cytopathic effect of EV recognized; instead that of HPV3 and related types was seen. No evidence for productive EV HPV DNA replication was obtained for the three specimens that could be further analyzed by in situ hybridization. Our data suggest that HPV3 infection favors infection with EV HPV in immunosuppressed patients but that the full expression of EV HPV is usually restricted as in the general population.

Early promoters of genital and cutaneous human papillomaviruses are differentially regulated by the bovine papillomavirus type 1 E2 gene product

The physical state of the human papillomavirus (HPV) genome is usually different in malignant lesions of the skin, in which it is generally found in episomal form, and genital mucosa, in which it is frequently integrated with disruption of the E2 gene. Using chimeric or natural HPV promoters in the presence of the bovine papillomavirus type 1 E2 gene product, we observed transcription activation or repression, depending on the distance of E2-binding motifs from the start site. We found a clear difference in the positions of E2-binding motifs in cutaneous and genital HPVs that may partly explain the selective pressure for genome integration of genital HPV types in malignant lesions.

Human papillomavirus in oral verrucal-papillary lesions. A comparative histological, clinical and immunohistochemical study

The purpose of this study was to determine the presence of Human Papillomavirus (HPV) virions in the verrucal-papillary (OVP) lesions by clinical, histological and immunohistochemical [peroxidase-antiperoxidase (PAP) features]. Thirty seven positive cases were compared with 47 negative cases. Considerable overlapping of clinical and histological features can be seen among all these lesions. The study provides evidence that there are no clinical or histologic features with taken alone are strongly correlated with the presence of virions in oral lesions.

Screening for high- and low-risk human papillomavirus types in single routine cervical smears by non-isotopic in situ hybridization

Routine cervical smears (n = 262) from a Sexually Transmitted Diseases clinic were screened by non-isotopic in situ hybridization (NISH) stratifying human papillomavirus (HPV) infections into HPV6/11 (low risk) and HPV16/18/33 (high risk) categories. Of 188 patients with cytologically normal smears, HPV sequences were demonstrated in 41%. Of the 128 cases analysed by dual NISH, 16% contained low risk, 20% high risk and 5% both groups. In patients with cytological evidence of wart virus infection (WVI) only, 54% (n = 50) contained high-risk and 22% low-risk HPV types. The comparable incidences in CIN1/2 plus WVI (n = 24) were not significantly different: 54% and 17%, respectively. Cytological criteria underestimate the prevalence of HPV infection in patients with cytologically normal smears. This represents either 'occult' or 'latent' infection. The identical prevalence of HPVB16/18/33 in WVI only, and CIN1/2 plus WVI, suggests that the cytopathic effect induced by these HPVs may represent one end of a spectrum of morphological change which progresses to cervical intraepithelial neoplasia (CIN).

A morphologic, pathologic, and virologic study of anogenital warts in men

BACKGROUND AND DESIGN

Infection with human papillomavirus (HPV) in the anogenital region is associated with benign papillomas (condyloma acuminatum), subtle verrucous changes, subclinical infection, and malignant lesions. Although both men and women are affected, much of the investigation has been directed toward women in the study of cervical and vulvar carcinoma. The current investigation focuses on HPV infection in men. This study was undertaken to correlate the clinical spectrum of disease in our population of male patients with histopathologic features, immunoperoxidase staining for viral capsid antigen, and viral typing. Genital lesions from 26 patients were examined and tested prospectively over a 1-year period.

RESULTS

The 26 lesions examined demonstrated variable morphologic features with regard to location, size, surface characteristics, and color. Histopathologic features were consistent with the diagnosis of venereal warts, but not necessarily diagnostic. Three of five standard histopathologic criteria were present in only 71% of the specimens. Despite the morphologic variability and the indeterminant histopathologic findings, 20 of 23 lesions positive for the genital tract HPV types tested contained HPV types 6 and/or 11.

CONCLUSIONS

We conclude that the morphologic appearance of anogenital warts does not necessarily correlate with HPV type. Histopathologic study is helpful in excluding other diagnoses but may be indeterminant in the diagnosis of venereal warts. All men with anogenital warts should be counseled, treated, and undergo follow-up regardless of HPV type.

Hyperkeratotic and verrucous skin lesions on lower extremities of leprosy patients

Three morphological varieties of hyperkeratotic and verrucous skin lesions on the anterior aspect of ankle joints in patients with leprosy are described: (i) verrucous lesions with thread-like horny projections similar to filiform warts; (ii) irregular compact hyperkeratotic lesions with deep fissures in between; and (iii) hyperkeratotic lesions with linear fissures corresponding to the transverse creases on the anterior aspect of the ankle. Chemical cautery was useful for the treatment of the first two varieties, and a potent topical corticosteroid with salicylic acid was useful for the third.

Molecular and biological characterization of cottontail rabbit papillomavirus variant DNA sequences integrated in the VX7 carcinoma

The transplantable VX7 carcinoma was derived from a tumor induced by a recoverable strain of cottontail rabbit papillomavirus (CRPV) able to replicate in domestic rabbits. Low levels of late viral gene expression have been retained through serial propagation in rabbits. We have cloned and characterized the three major types of CRPV sequences integrated in this tumor, a genome-length 8-kb DNA molecule and two rearranged 9- and 3.8-kb molecules. The VX7 8-kb DNA displays only a few differences in its restriction map, when compared to the wild-type (wt) CRPV DNA. The VX7 9- and 3.8-kb DNAs derive from the VX7 8-kb DNA since they share the same restriction site polymorphism. The VX7 9-kb DNA contains a duplication of the E6 open reading frame. The VX7 3.8-kb DNA results from the deletion of most of the E region and the insertion, between the borders of the deletion, of 174-nucleotide-long segment of the long control region potentially driving the expression of a truncated L2 protein. Both VX7 9- and 3.8-kb species potentially allow the expression of abnormal E6 fusion proteins. Nineteen point mutations were detected in the 3.8-kb DNA, compared to the wt CRPV DNA. None of these molecules were able to induce warts in domestic rabbits, in contrast to wt CRPV DNA. Furthermore, when cloned VX7 DNAs were inoculated together with wt CRPV DNA, none of the VX7 CRPV sequences, as identifiable by their specific restriction enzyme cleavage patterns, could be detected in the resulting warts. This suggests that CRPV sequences integrated in the VX7 carcinoma are no longer able to replicate as episomes, which might be a prerequisite for the production of warts.

Detection and analysis of human papillomavirus type 1 infection of skin warts from a dermatology clinic in Taiwan by southern hybridization

Thirty cases of skin warts from the Dermatology Clinic at Tri-Service General Hospital were analyzed for the presence of human papillomavirus type 1 sequences by Southern blot hybridization. Thirteen of the 30 cases were HPV-1 positive. The prevalence was 43%. Episomal HPV-1 sequences were detected in 11 of 13 HPV-1 positive cases. There are two cases which probably contained integrated forms, one contained the higher molecular weight bands, and the other with 6 kb viral genome may be the result of rearrangement and deletion. Histological studies from HPV-1 positive specimens also indicated the typical features of HPV infection. Some cases with high copy number had a high frequency of inclusion bodies. Chi-square analysis showed that HPV-1 prevalence is not related to sex and different lesion locations, but the prevalence of HPV-1 in recurrent lesions is higher than that of initial lesions.

Ribavirin mitigates wart growth in rabbits at early stages of infection with cottontail rabbit papillomavirus

The challenge to develop antiviral agents effective against DNA viruses such as human papillomavirus (HPV) has been dependent on finding an animal model which mimics the human forms of the disease. We have used an existing model system for the purpose of measuring the effect of antiviral drugs on the inhibition of growth of these lesions. This was based upon domestic rabbits which efficiently grow cutaneous papillomas (warts) when infected with cottontail rabbit papillomavirus (CRPV). One agent which had shown significant success in achieving these goals was ribavirin. Ribavirin was administered intradermally shortly prior to infection at multiple sites with CRPV. Following daily injections of this drug for eight weeks, we have shown a dose-dependent response which had markedly reduced the number of warts, the time of first appearance of warts and reduced the tumor mass as compared to placebo-treated control animals. At the highest dose of ribavirin tested, 30 mg/kg/day, compared to controls, the average reduction in the number of warts was 52%, the average time of first appearance of warts was 49% longer, and the average mass of the warts was reduced by 98%. No detectable antibodies to CRPV were observed in any of the animals. The only side effects which were observed was focal alopecia, and a decrease in body growth upon prolonged treatment, both of which were completely reversible. Pharmacokinetic studies established the metabolism of ribavirin over a 24-h period of time. Ribavirin administered beginning 12 or 30 days post-infection, while not reducing the number of warts, slightly retarded the growth of warts as determined by date of first appearance of warts and mass of warts.

Antigenic and immunogenic epitopes shared by human papillomavirus type 16 and bovine, canine, and avian papillomaviruses

All types of papillomaviruses (PV) share common, so-called group-specific epitopes. To identify the major group-specific epitopes, we immunized 26 guinea pigs or rabbits with purified bovine PV type 1 (BPV), canine PV, or avian PV from the common chaffinch. The resulting hyperimmune sera, as well as a commercially available rabbit antiserum to BPV and seven monoclonal antibodies to BPV, were tested in an enzyme-linked immunosorbent assay with a set of 66 overlapping 20-amino-acid peptides representing the complete sequence of the major capsid proteins (L1 and L2) of human PV type 16 (HPV 16). Sera from the same animals before immunization were used as controls. The minimal reactive epitopes within each peptide were further characterized by testing of truncated peptides. The cross-reactive epitopes were clustered in two regions of L1, an internal region (at positions 171 to 235), which contained three epitopes, and the more reactive region at the carboxy terminus (at positions 411 to 475), which contained six epitopes. The most reactive of the HPV 16 broadly cross-reactive epitopes was a carboxy-terminal epitope which had the sequence DTYRF and which reacted with nine of the antisera to BPV, canine PV, or avian PV, with the commercially available rabbit antiserum to BPV, and also with a mouse monoclonal antibody to BPV. Antipeptide antisera to all of the HPV 16 L1 peptides and to the most antigenically reactive of their truncated analogs were made in guinea pigs. Antipeptide antisera reactive with BPV were obtained for three of the cross-reactive epitopes, and one of these antisera allowed highly sensitive detection of group-specific PV antigen by immunoperoxidase staining.

Verrucous cyst

Human papillomavirus has been detected in a variety of cutaneous premalignant and malignant conditions, as well as in benign cutaneous warts. Changes consistent with epidermis papilloma virus infection occurring in epidermal cysts have recently been reported in the dermatologic literature only in plantar epidermal cysts. We report five examples of a form of cutaneous cyst that is histologically distinctive and that has not been previously reported, to our knowledge. We describe five cases of epidermal cysts showing marked verrucous changes of their stratified squamous inner linings, some of which also show proliferative changes. Human papillomavirus genomes were detected via polymerase chain reaction. None of the DNA probes for Southern blot hybridization demonstrated homology with the human papillomavirus types usually associated with cutaneous warts or carcinoma. We believe this cyst to represent a newly described manifestation of human papillomavirus infection, and propose the name verrucous cyst for this entity. Further studies may reveal the specific human papillomavirus type(s) associated with the verrucous cyst.

Structures of bovine and human papillomaviruses. Analysis by cryoelectron microscopy and three-dimensional image reconstruction

The structures of bovine papillomavirus type 1 (BPV-1) and human papillomavirus type 1 (HPV-1) were determined at 2.5 nm resolution by cryoelectron microscopy and three dimensional image reconstruction techniques. As expected, the reconstructions showed that both viruses consist of a T = 7 icosahedral capsid (approximately 60 nm in diameter) which surrounds a nucleohistone core. The capsid morphologies of the two viruses are nearly indistinguishable. Each capsid consists of a shell layer (approximately 2 nm thick) of nearly continuous density from which capsomers project radially to a maximum height of approximately 5.8 nm. The five-coordinate (pentavalent) and six-coordinate (hexavalent) capsomers both exhibit distinct five-fold axial symmetry as was observed for SV40 and polyoma viruses. Thus, both genera (papilloma and polyoma) of the papovavirus family have now been shown to have the characteristic "all-pentamer" capsid construction. BPV-1 and HPV-1 capsomers consist of a thick (8.6 nm diameter) trunk that broadens distally to form a regular five-pointed, star-shaped head, and proximally to create the shell layer where capsomers associate. A cylindrical channel (approximately 2.8 nm diameter) extends along the axis of each capsomer from the interior of the virus to a point approximately half way to the capsomer surface. Computationally sectioned views of individual capsomers displayed at decreasing radii show that each of the five capsomer subunits (in both pentavalent and hexavalent capsomers) makes a pronounced (30 degrees) left-handed twist just above the outer surface of the capsid shell. Similar views of the reconstructions also clarify the morphology of intercapsomer contacts. For example, they show how hexavalent capsomers coordinate six neighboring capsomers despite the fact that they contain only five subunits. The system of intercapsomer contacts is indistinguishable in BPV-1 and HPV-1, but quite different from that reported for polyoma virus capsids assembled in vitro from the major capsid protein, VP1 (D. M. Salunke, D. L. D. Caspar, and R. L. Garcea. 1989. Biophys. J. 56:887-900). Thus, because both polyoma and papilloma viruses have all-pentamer capsids, it appears that intracapsomer subunit-subunit interactions which stabilize pentameric capsomers are better preserved evolutionarily than those involved in capsomer-capsomer contacts.

Benign human papillomavirus infection in renal transplant recipients

Warts and cutaneous squamous cell carcinomas are common complications of immunosuppression. We studied a total of 189 renal transplant recipients clinically for such lesions. The incidence of warts increased steadily after transplant, such that of patients transplanted for more than 5 years, 92% were found to have warts and 65% had more than five warts each. DNA extracted from scrapings of their warts showed they carried the same human papillomavirus types as the general population, and not the unique set found on patients with epidermodysplasia verruciformis (who share with transplant recipients an increased incidence of warts and squamous cell carcinomas).

Ultrastructural visualization of human papillomavirus DNA in verrucous and precancerous squamous lesions

Human papillomavirus (HPV) DNA was ultrastructurally localized by the non-isotopic in situ hybridization technique in formalin-fixed, paraffin-embedded specimens of verruca vulgaris of the skin, condyloma acuminatum of the penis and severe dysplasia of the uterine cervix. Biotinylated DNA probe cocktails were employed for the visualization of HPV-DNA, types 6 and 11 (HPV 6/11) and types 16 and 18 (HPV 16/18). The papillomavirus genus-specific antigen was also visualized by pre-embedding immunoelectron microscopy using rabbit antiserum. In verruca vulgaris, HPV antigen-positive 50-60 nm-particles of mature viral size were observed in the nuclei of the granular cells and parakeratotic cells with perinuclear haloes, whereas HPV 6/11 and HPV 16/18 DNA were negative. In condyloma acuminatum, the nuclei were positive for the HPV antigen and HPV 6/11 DNA, but were negative for HPV 16/18 DNA. More cells were labeled for the viral DNA than for the viral antigen. The ultrastructural observation indicated the presence of the naked (plasmid) viral DNA as fine particles sized 15-20 nm. In the dysplastic cervical mucosa, dot-like positivity of HPV 16/18 DNA was recognized. The HPV antigen and HPV 6/11 DNA were undetectable. HPV 16/18 DNA was localized in part of the nuclear chromatin. This pattern of localization may suggest integration of the viral DNA into the host cell DNA.

In situ detection of HPV DNA in oral mucosal lesions. A comparison of two hybridization kits

The purpose of this study was to compare the sensitivity of ViraType in situ hybridization kit (Life Technologies, Inc. [LT] and PathoGene (Enzo Diagnostics, Inc. [ED]) in situ hybridization kit for human papillomavirus (HPV) DNA detection in oral tissue. Forty benign oral lesions histologically suspicious for HPV infection were analyzed. Specimens were hybridized with DNA probes specific for HPV types 6/11, 16/18, and 31/33/35 [LT] and HPV types 6/11, 16/18, and 31/33/51 [ED]. Positive hybridization reactions were seen for HPV DNA type 6/11 only. Hybridization occurred significantly more often (p less than 0.01, McNemar Exact Test) in LT probed specimens (20/40) than ED assayed sections (12/40). HPV DNA sequences were found in 100% condyloma acuminata (13/13), 100% verruca vulgaris (4/4), and 13% squamous papilloma (3/23) using the LT system. The ED probes yielded positive signals in 77% condyloma acuminata (10/13), 25% verruca vulgaris (1/4), and 4.4% squamous papilloma (1/23). A more intense hybridization signal was exhibited using the LT system. The results indicate that the LT probes and detection reagents are more sensitive for detecting HPV DNA in oral mucosal specimens.

Verruca vulgaris of the larynx. Demonstration of human papillomavirus types 6/11 by in situ hybridization

Verruca vulgaris of the larynx (VVL) is a distinctly uncommon lesion related to the human papillomavirus (HPV). The clinical and pathologic features of a case involving the true vocal cords of a 37-year-old woman are presented and compared with the seven cases previously reported in the English language literature. Papillomavirus capsid antigen was detected in the excised tissue on immunostaining, and viral particles were seen by electron microscopy. In situ hybridization with biotinylated DNA probes clearly demonstrated HPV types 6/11. To our knowledge, this is the first case of VVL in which the virus associated with VVL has been genotyped. The results were unexpected because verruca vulgaris of the skin, lips, and oral cavity is associated with HPV types 2 and 4. This implies that verruca vulgaris can be caused by HPV types other than 2 and 4. In addition, since HPV types 6 and 11 are also the same genotypes associated with multiple papillomatosis of the larynx, it further indicates that VVL is virologically more related to multiple papillomatosis of the larynx than to its counterpart on the skin, lips, and oral cavity. The clinical and pathologic features that distinguish VVL from other similar lesions of the larynx are also discussed.

In situ hybridization analysis of human papillomavirus DNA in oral mucosal lesions

Commercial biotinylated DNA probes specific for human papillomavirus (HPV) types 6 and 11; 16 and 18; and 31, 33, and 35 were used for in situ hybridization analysis of 105 oral mucosal specimens from 5 cases of verruca vulgaris, 15 cases of condyloma acuminatum, 30 cases of squamous papilloma, 20 cases of hyperkeratosis/acanthosis, 15 cases of epithelial dysplasia, 5 cases of carcinoma in situ, and 15 cases of squamous cell carcinoma. Positive hybridization signals were found in 26 specimens (24.8%). Only HPV-6/11 was detected. HPV DNA occurred significantly more often (p less than 0.005, chi-square analysis) in condyloma acuminatum (100%) and verruca vulgaris (100%) than squamous papilloma (13.3%), hyperkeratotic/acanthotic lesions (10%), and malignant and premalignant lesions (0%). The tongue (19.1%) and labial epithelium (17.1%) were infected most frequently. Nuclear reaction products indicating HPV infection were associated primarily with koilocytes. These results demonstrate the usefulness of commercial biotinylated probes for HPV DNA analysis in routine paraffin-embedded lesion specimens. They confirm HPV involvement in benign lesions of the oral mucosa but fail to associate HPV infection with oral cancer and precancer.

Use of human papillomavirus type 11 virions in an ELISA to detect specific antibodies in humans with condylomata acuminata

Human papillomavirus types 6 and 11 (HPV-6 and HPV-11) are the major aetiological agents of condylomata acuminata. Serological studies of this disease have been difficult to perform and interpret because native, type-specific antigens have not been available. In particular, since these viruses have not been propagated in vitro and sufficient quantities of virions are not present in lesions, virus particles have been difficult to obtain. In the present study, we used HPV-11 particles, obtained from human tumours produced in athymic mice, as antigen in an ELISA to compare antibody responses between 46 patients with biopsyproven condylomata acuminata and 44 controls. The median [interquartile range] of the absorbance values for the condylomata acuminata and the control groups were respectively 0.324 [0.183, 1.029] and 0.118 [0.047, 0.286] (P = 0.0001). Thirty-three per cent of the absorbance values in the condylomata acuminata group were higher than any of those of the control group. Sera from patients whose biopsies contained the papillomavirus common antigen were more reactive than sera from patients whose biopsies did not contain it (P = 0.0014). This study demonstrates the presence of specific antibodies directed at native HPV-11 viral particles in the sera of patients with condylomata acuminata, and describes a test which can be used in future serological studies of this common sexually transmitted disease.

Human papillomavirus segregation patterns in genital and nongenital warts in prepubertal children and adults

This study compared the segregation patterns of human papillomavirus (HPV) in genital and nongenital warts in prepubertal children and adults. HPV 2 was detected in most nongenital warts in children and adults, whereas neither HPV 6 or 11 was detected at nongenital sites in either group with the use of in situ or Southern blot hybridization analyses. Of nine genital tract lesions in children. HPV 2 was detected in two and HPV 6 or 11 in six. More than 90% of cases of regional tract condylomata in adults contained HPV 6 or 11. HPV 2 was not detected in any of 99 genital tract lesions in adults. It is concluded that HPV 6/11 cannot proliferate at nongenital cutaneous sites and HPV 2 can proliferate in the genital tract of children but not adults. Thus, the detection of HPV 6 or 11 in a genital wart in a child implies, assuming cutaneous transmission, infection from a genital site, whereas the detection of HPV 2 presumes nongenital transmission.

Clinical manifestations of human papillomavirus infection in nongenital sites

Our knowledge of warts dates thousands of years. Most warts represent no more than a transient infection in the hands and feet of children and adults. With the relatively recent medical advances permitting the prolonged survival of immunocompromised hosts, however, HPV-induced lesions have become an important problem. In these patients, lesions represent a recurring, intractable infection that predisposes the patient to the development of skin cancer. Such problems have been appreciated for some time in patients with EV. Newer laboratory techniques have led to an increasing number of clinical entities linked with an HPV cause in the nonimmunosuppressed host. Although evidence incriminating HPV as a causative factor for genital cancers of the cervix and the skin continues to mount, such evidence for nongenital Bowen's disease, certain squamous cell carcinomas of the skin, keratoacanthomas, and other tumors of the skin also has begun to grow. It is to be hoped that continued advances in molecular biologic techniques will further delineate the relationship between HPV and these conditions, lead to an HPV classification scheme that is more utilitarian from a clinical point of view, and ultimately lead to improved treatment.

Densitometric determination of human papillomavirus DNA quantities by chromato-scanning in the fluorescence mode

The quantitation of human papillomavirus DNA isolated from warts by chromato-scanning (fluorescence mode) photographs of ethidium bromide-stained agarose gels is described. Excitation at 200 nm (with a cutoff filter at 400 nm) generates fluorescence from the white portion of the printing paper. The fluorescent intensity correlated with the quantities of DNA in the band of interest. The amounts of DNA were determined using calibration curves of approximately the same size as lambda phage DNA fragments. This general method of quantification is applicable to photographs of other types of polynucleotides capable of being separated and stained in a gel medium.