Purification and Characterization of Antibodies in Single-Chain Format against the E6 Oncoprotein of Human Papillomavirus Type 16.

In Human Papillomaviruses- (HPV-) associated carcinogenesis, continuous expression of the E6 oncoprotein supports its value as a potential target for the development of diagnostics and therapeutics for HPV cancer. We previously reported that the I7 single-chain antibody fragment (scFv) specific for HPV16 E6, expressed as an intrabody by retroviral system, could inhibit significantly the growth of cervical cancer cells in vitro and was even able to reduce tumor development in experimental HPV-related cancer models. Nevertheless, for the development of therapeutic tools to be employed in humans, it is important to achieve maximum safety guarantee, which can be provided by the protein format. In the current study, two anti-16E6 scFvs derived from I7 were expressed in E. coli and purified in soluble form by affinity chromatography. Specificity, sensitivity and stability in physiologic environment of the purified scFvs were demonstrated by binding studies using recombinant 16E6 as an antigen. The scFvs functionality was confirmed by immunofluorescence in cervical cancer cells, where the scFvs were able to recognize the nuclear E6. Furthermore, an antiproliferative activity of the scFvI7nuc delivered in protein format to HPV16-positive cell lines was observed. Our results demonstrate that functional anti-16E6 scFvs can be produced in E. coli, suggesting that such purified antibodies could be used in the diagnosis and treatment of HPV-induced malignancies.

Frequent and abundant Merkel cell polyomavirus detection in urban wastewaters in Italy.

Viruses strongly associated with human cancer have recently been detected in urban sewages and other water environments worldwide. The aim of the present study was to assess the presence of Merkel cell polyomavirus (MCPyV), a newly discovered, potentially oncogenic human virus, in urban sewage samples collected at wastewater treatment plants (WTPs) in Italy. A total of 131 raw sewage samples were collected from 21 WTPs in nine Italian regions and analyzed by both qualitative (PCR/nested) and quantitative (Real-Time qRT-PCR) methods. Of these, 66 samples (50.3 %) were positive for MCPyV by the qualitative assay. Quantitative data showed high viral loads in wastewaters (mean, 1.5E + 05 genome copies/liter). High concentrations of MCPyV were found in all WTPs under study, suggesting a wide circulation of the virus and thus the need for further studies to assess possible waterborne MCPyV transmission.

Antibodies in single-chain format against tumour-associated antigens: present and future applications.

The recombinant antibodies in single-chain format (scFv) have found broad applications in both therapeutic and diagnostic fields. Tumour-associated antigens (TAAs) are proteins or other molecular species expressed in a specific tumour type, that can be targeted for diagnostic and immunotherapy purposes. The possibility of obtaining highly selective and efficacious scFvs makes them appropriate tools to target TAAs. The approach utilised for targeting depends on the nature of TAAs and their cell localisation. Tumour antigens displayed on the cell surface can be recognised by scFvs coupled to radioisotopes, toxins and enzymes to be used in cancer diagnosis and therapy. Intracellular tumour antigens can be targeted by scFvs expressed as "intracellular antibodies". This review reports the existing scFv-based formats, hints of their generation and pharmacokinetics, and a description of the most promising TAAs. It also provides an update of in vitro, preclinical and clinical studies using scFvs against TAAs for cancer diagnosis and treatment, with their merits and limits.

Up-regulation of proliferating cell nuclear antigen (PCNA) is closely associated with high-risk human papillomavirus (HPV) and progression of cervical intraepithelial neoplasia (CIN), but does not predict disease outcome in cervical cancer.

OBJECTIVE: Proliferating cell nuclear antigen (PCNA) is essential for DNA replication of mammalian cells and their small DNA tumour viruses. The E7 oncoprotein of high-risk human papillomavirus (HPV) is known to activate PCNA, shown to be up-regulated in CIN and cervical cancer (CC), but still incompletely studied as an intermediate endpoint marker in this disease. MATERIAL AND METHODS: As part of our HPV-PathogenISS study, a series of 150 CCs and 152 CIN lesions were examined using immunohistochemical (IHC) staining for PCNA, and tested for HPV using PCR with three primer sets (MY09/11, GP5+/GP6+, SPF). Follow-up data were available from all SCC patients, and 67 of the CIN lesions had been monitored with serial PCR for HPV after cone treatment. RESULTS: Expression of PCNA increased in parallel with the grade of CIN, with major up-regulation upon transition to CIN3 (OR 21.77; 95%CI 6.59-71.94) (p = 0.0001). Intense PCNA expression was 100% specific indicator of CIN, with 100% PPV, but suffers from low sensitivity (34.8%) and NPV (10.8%). PCNA expression was also significantly associated to HR-HPV with OR 3.02 (95%CI 1.71-5.34) (p = 0.0001), and this association was not confounded by the histological grade (Mantel-Haenszel common OR = 2.03; 95%CI 1.06-3.89) (p = 0.033). Expression of PCNA did not predict clearance/persistence of HR-HPV after treatment of CIN, and it was not a prognostic predictor in CC in univariate or in multivariate analysis. CONCLUSIONS: Up-regulation of PCNA was closely associated with HR-HPV and progressive CIN, most feasibly explained by the abrogation of normal cell cycle control by the E7 ongogene, reverting the p21(Cip1)-mediated inhibition of PCNA. However, the fact that PCNA is also expressed in normal squamous epithelium precludes the use of this marker as a potential screening tool for CC.

Upregulation of telomerase (hTERT) is related to the grade of cervical intraepithelial neoplasia, but is not an independent predictor of high-risk human papillomavirus, virus persistence, or disease outcome in cervical cancer.

Telomerase activation and telomere maintenance are essential for cell immortalization and represent a rate-limiting step in cancer progression. The E6 oncoprotein of high-risk human papillomavirus (HPV) is known to activate telomerase, but its expression in CIN lesions and its prognostic value in cervical cancer (CC) are still incompletely understood. As part of our HPV-PathogenISS study, a series of 150 CCs and 152 CIN lesions were examined using immunohistochemical (IHC) staining for hTERT (telomerase reverse transcriptase), and tested for HPV using PCR with three primer sets (MY09/11, GP5(+)/GP6(+), SPF). Follow-up data were available from all SCC patients, and 67 CIN lesions had been monitored with serial PCR for HPV after cone treatment. Expression of hTERT was increased in parallel with the grade of CIN, with major up-regulation upon transition to CIN3 (OR 18.81; 95% CI 8.48-41.69; P = 0.0001). Positive hTERT expression was 90% specific indicator of CIN, with 98.7% PPV, but suffers from low sensitivity (57.5%) and NPV (14.3%). hTERT expression was also significantly associated to HR-HPV with OR 3.38 (95% CI 1.90-6.02; P = 0.0001), but this association was confounded by the histological grade (Mantel-Haenszel common OR = 1.83; 95% CI 0.92-3.79; P = 0.086). Expression of hTERT did not predict clearance/persistence of HR-HPV after treatment of CIN, and it was not a prognostic predictor in cervical cancer in univariate or multivariate survival analysis. It was concluded that up-regulation of hTERT was closely associated with HR-HPV, due to activation by the E6 oncoprotein. hTERT is a late marker of cervical carcinogenesis, significantly associated with progression to CIN3. Theoretically, a combination of hTERT assay (showing high SP and PPV) with another test showing high SE and high NPV (e.g. Hybrid Capture 2 for HPV), should provide an ideal screening tool capable of high-performance detection of CIN lesions.

Upregulation of nuclear factor-kappaB (NF-kappaB) is related to the grade of cervical intraepithelial neoplasia, but is not an independent predictor of high-risk human papillomavirus or disease outcome in cervical cancer.

Nuclear factor-kappaB (NF-kappaB) has a pivotal function in controlling a wide variety of gene functions, and has shown to be constitutively activated in many human cancers. The molecular links of NF-kappaB to oncogenic human papillomavirus (HPV) in cervical intraepithelial neoplasia (CIN) lesions and its prognostic value in cervical cancer (CC) are incompletely understood. As part of our HPV-PathogenISS study, a series of 150 squamous-cell carcinomas (SCCs) and 152 CIN lesions were examined using immunohistochemical staining for NF-kappaB, and tested for HPV using PCR with three primer sets (MY09/11, GP5+/GP6+, and SPF). Follow-up data were available from all SCC patients, and 67 CIN lesions had been monitored with serial PCR for HPV clearance/persistence after cone treatment. Cytoplasmic NF-kappaB expression was associated with CIN3/cancer at OR 3.55 (95% CI, 1.79-7.05), while nuclear NF-kappaB expression had an OR of 21.90 (95% CI, 2.96-161.74) (P = 0.0001). Strong nuclear expression was a rare event (8.8%) also in CC, but it was related to high-risk human papillomavirus (HR-HPV) detection, with OR 2.15 (95% CI, 1.08-4.30) (P = 0.022). This association was confounded, however, by the histological grade (Mantel-Haenszel common OR = 1.46; 95% CI, 0.70-3.03) (P = 0.308). Cytoplasmic or nuclear NF-kappaB expression did not predict clearance/persistence of HR-HPV after treatment of CIN, and neither one proved to be a prognostic predictor in CC. Overexpression of cytoplasmic NF-kappaB is significantly associated with progression to CIN3 and cancer. This is paralleled by only a slight increase in nuclear expression of NF-kappaB, which could be explained by the mechanisms whereby HR-HPVs escape from the transcriptional control of NF-kappaB, i.e., E7-mediated impaired nuclear translocation of cytoplasmic NF-kappaB, and E6-conditioned attenuated NF-kappaB (p65)-dependent transcriptional activity.

Down-regulation of E-cadherin is closely associated with progression of cervical intraepithelial neoplasia (CIN), but not with high-risk human papillomavirus (HPV) or disease outcome in cervical cancer.

OBJECTIVE: E-cadherin plays a pivotal role in maintenance of normal adhesion in epithelial cells but has also been shown to suppress tumour invasion and participate in cell signalling. Known to be capable of reversing the invasive phenotype of high-risk human papillomavirus (HPV)-transformed keratinocytes, E-cadherin is down-regulated in CIN and cervical cancer (CC), but still incompletely studied as an intermediate endpoint marker in this disease. MATERIAL AND METHODS: As part of our HPV-PathogenISS study, a series of 150 CCs and 152 CIN lesions were examined using immunohistochemical (IHC) staining for E-cadherin, and tested for HPV using PCR with three primer sets (MY09/11, GP5+/GP6, SPF). Follow-up data were available from all squamous cell carcinoma (SCC) patients, and 67 CIN lesions were monitored with serial PCR for HPV after cone treatment. RESULTS: Expression of E-cadherin was reduced in parallel with the increasing grade of CIN, with major down-regulation upon transition to CIN3 and further to invasive cancer (OR 6.95; 95% CI 2.67-18.09) (p = 0.0001). Negative markedly reduced E-cadherin expression was a 90.9% specific indicator of CIN, with 97.4% PPV, but suffered from low sensitivity (27.0%) and NPV (9.1%). E-cadherin expression was completely unrelated to HR-HPV (p = 0.982), and did not predict clearance/persistence of HR-HPV after treatment of CIN. Similarly, E-cadherin expression was not a prognostic predictor of CC in univariate or multivariate analysis. CONCLUSIONS: Down-regulation of E-cadherin was closely associated with progressive CIN and cell proliferation. It is tempting to speculate that part of this cell proliferation is mediated through the canonic Wnt signalling pathway, after liberation of transcriptionally competent beta-catenin from the E-cadherin/catenin complex, most notably orchestrated by E6 and E7 oncoproteins of HR-HPV. Such a liberation of beta-catenin would abrogate the negative transcriptional control of E-cadherin on the Lef/TCF/beta-catenin responsive genes. The exact role of HR-HPV oncoproteins E6 and E7 in this process remains to be seen in future studies.

Matrix metalloproteinase-2 (MMP-2) and its tissue inhibitor (TIMP-2) are prognostic factors in cervical cancer, related to invasive disease but not to high-risk human papillomavirus (HPV) or virus persistence after treatment of CIN.

OBJECTIVE: Matrix metalloproteinase-2 (MMP-2) and its tissue inhibitor (TIMP-2) are important regulators of cancer invasion and metastasis. Their associations to high-risk (HR) human papillomavirus (HPV) in cervical intra-epithelial neoplasia (CIN) and cervical cancer (CC) are unexplored and their prognostic significance in CC remains controversial. MATERIALS AND METHODS: As part of our HPV-PathogenISS study, a series of 150 CCs and 152 CIN lesions were examined using immunohistochemical (IHC) staining for MMP-2 and TIMP-2 and tested for HPV using PCR with 3 primer sets (MY09/11, GP5+/GP6+, SPF). Follow-up data were available from all squamous cell carcinoma patients and 67 CIN lesions had been monitored with serial PCR for HPV after cone treatment. RESULTS: MMP-2 increased with the grade of CIN, with major up-regulation upon transition to invasive cancer (OR 20.78) (95%CI 7.16-60.23) (p=0.0001). TIMP-2 retained its normal expression until CIN3, with dramatic down-regulation in invasive disease (p=0.0001 for trend). Thus, the MMP2:TIMP-2 ratio increased with progressive CIN, exceeding the value 1.0 only in invasive disease. Both MMP-2 and TIMP-2 are highly specific (TIMP-2; 100%) discriminators of CIN with 100% positive predictive value (TIMP-2), but suffer from low sensitivity and negative predictive value. Neither MMP-2 nor TIMP-2 showed any significant association with HR HPV or virus persistence/clearance. TIMP-2 (but not MMP-2) was a significant predictor of survival in univariate (Kaplan-Meier) analysis (p=0.007), but lost its significance in multivariate (Cox) analysis. CONCLUSION: The activities of MMP-2 and TIMP-2 in cervical carcinogenesis seem to be unrelated to HR-HPV The inverse MMP-2:TIMP-2 ratio is a sign of poor prognosis. A combination of a TIMP-2 assay with another test showing high SE and high NPV (e.g., HCII for HPV) should provide a potential screening tool capable of accurate detection of CIN.

Exploiting the plant secretory pathway to improve the anticancer activity of a plant-derived HPV16 E7 vaccine.

The human papillomavirus 16 (HPV16) E7 oncoprotein can be considered a "tumor-specific antigen", and therefore it represents a promising target for a therapeutic vaccine against HPV-associated tumors. Efficient production of E7 protein with a plant-based transient expression system has been already described and it was demonstrated that E7-containing crude plant extracts confer partial protection against tumor challenge in a mouse model system. Before adopting the plant-based system as a cost-effective method for the production of an E7-based anti-cancer vaccine, some aspects, such as the oncoprotein yield, need further investigation. In the present study, we report the transient expression, mediated by a potato virus X (PVX)-derived vector, of the E7 protein targeted to the secretory system of Nicotiana benthamiana plants by using a plant-derived signal sequence. Targeting the antigen to the secretory pathway enhanced the E7 protein expression levels about five-fold. Mice immunized by s.c. administration with crude foliar extracts containing E7 showed strong stimulation of cell-mediated immune response after five boosters, as detected by ELISPOT. After challenging with the E7-expressing C3 tumor cells, tumor growth was completely inhibited in 80% of the vaccinated animals and a drastic reduction of tumor burden was observed in the remaining tumor-affected mice. These data demonstrate that, by enhancing E7 yield, it is possible to improve the anti-cancer activity of the plant-based experimental vaccine and open the way for a large-scale production of the E7 protein which could be purified or used as in planta formulation, also suitable for oral therapeutic vaccination.

Down-regulated nucleoside diphosphate kinase nm23-H1 expression is unrelated to high-risk human papillomavirus but associated with progression of cervical intraepithelial neoplasia and unfavourable prognosis in cervical cancer.

OBJECTIVE: One of the factors leading to an invasive phenotype is the nm23 family of metastases-associated genes. Of the six known members, nm23-H1 is the most frequently studied potential anti-metastatic gene in cervical cancer. However, the possible molecular links to oncogenic human papillomavirus (HPV) are completely unexplored as yet. MATERIALS AND METHODS: As a part of the HPV-Pathogen Istituto Superiore di Sanità study, a series of 150 squamous cell carcinomas (SCCs) and 152 cervical intraepithelial neoplasia (CIN) lesions were examined by immunohistochemical staining for nm23-H1, and tested for HPV by polymerase chain reaction (PCR) with three sets of primers (MY09/11, GP5(+)/GP6(+) and short PCR fragment). Follow-up data were available on all patients with SCC, and 67 CIN lesions were monitored by serial PCR for clearance or persistence of HPV after cone treatment. RESULTS: A linear decrease (p = 0.001) was observed in nm23-H1 expression, starting from CIN1 (85% with normal expression), with the most dramatic down regulation on transition from CIN2 (70% normal) to CIN3 (39%) and further to SCC (25%). Reduced expression was associated with CIN3 or cancer at an odds ratio 8.72 (95% confidence interval 4.13 to 18.41). Nm23-H1 was of no use as a marker of the high-risk human papillomavirus (HR-HPV) type, and it did not predict clearance or persistence of HR-HPV after treatment of CIN. Importantly, nm23-H1 expression was a significant prognostic factor in cervical cancer, reduced expression being associated with lower survival (p = 0.022) in univariate analysis. In the multivariate (Cox) regression model, however, only the International Federation of Gynecology and Obstetrics stage (p = 0.001) and age (p = 0.011) remained independent prognostic predictors. CONCLUSIONS: Down-regulated nm23-H1 expression is markedly associated with progression from CIN2 to CIN3, and predicts poor prognosis in cervical cancer. Nm23-H1 down regulation is probably orchestrated by mechanisms independent of HR-HPV oncoproteins and is possibly related to the emergence of a proteolytic phenotype.

Aberrant expression of VEGF-C is related to grade of cervical intraepithelial neoplasia (CIN) and high risk HPV, but does not predict virus clearance after treatment of CIN or prognosis of cervical cancer.

AIMS: Increased angiogenesis leads to invasion in cervical cancer. Vascular endothelial growth factors (VEGFs) are involved in angiogenesis, but molecular links to the most important aetiological agent, human papillomavirus (HPV), need clarifying. MATERIAL/METHODS: Archival samples-150 squamous cell carcinomas (SCCs) and 152 cervical intraepithelial neoplasia (CIN) lesions-were examined immunohistochemically for anti-VEGF-C antibody and for HPV by polymerase chain reaction (PCR). Follow up data were available for all SCC cases, and 67 CIN lesions were monitored with serial PCR to assess HPV clearance/persistence after treatment. RESULTS: High risk (HR) HPV types were closely associated with CIN (odds ratio, 19.12; 95% confidence interval, 2.31 to 157.81) and SCC (27.25; 3.28 to 226.09). There was a linear increase of VEGF-C expression-weak in CIN1 and intense in CIN3 and SCC (20.49; 8.69 to 48.26). VEGF-C upregulation was a sensitive (93.5%; 95% CI, 90.1% to 96.9%) marker of HR-HPV type (4.70; 2.17 to 10.21), but lost its significance in multivariate regression-p16(INK4a) and survivin were equally strong independent predictors of HR-HPV. Aberrant expression of VEGF-C did not predict clearance/persistence of HR-HPV after treatment of CIN. In cervical cancer, VEGF-C had no prognostic value in univariate or multivariate survival analysis. After adjustment for HR-HPV, FIGO stage, age, and tumour grade, only FIGO stage and age remained independent prognostic predictors. CONCLUSIONS: VEGF-C is an early marker of cervical carcinogenesis, with linearly increasing expression starting from low grade CIN. VEGF-C expression is closely related to HR-HPV in cervical lesions, probably because of its p53 independent upregulation by the E6 oncoprotein of HR-HPV.

Immunological characterization of Toscana virus proteins.

The genome of Toscana virus (Bunyaviridae family, Phlebovirus genus) consists of three single stranded RNA segments (L, M, S), with negative polarity. The L and M segments contain a single ORF in viral complementary sense and the S segment contains two ORFs in "ambisense" orientation. The M segment codes for three proteins in 3'-5' genomic orientation: a 30 kDa non structural protein and two 65 kDa glycoproteins, GN, and GC. In this paper we report the expression in E. coli of the S segment ORFs and of three regions of the L ORF. The expressed proteins were used to produce monospecific polyclonal antibodies in mice. By using these antibodies the N and the NSs proteins were unequivocally assigned to the S viral-complementary and viral-sense ORFs, respectively, and the L protein to the L ORF. We have found that like N and L proteins, NSs protein is associated with the viral nucleocapsids in mature virions, suggesting its possible involvement in early events of viral replication. NSs protein was also found associated with cellular polysomes. In virus-infected cells the anti-L antibodies recognized proteins shorter than the full-length L protein, possibly products of L subgenomic segments. Interestingly these defective products were not found in mature virions, suggesting specific mechanisms in virion assembly.

Characterization of Toscana virus-defective interfering particles generated in vivo.

Toscana (TOS) virus stocks strongly interfering with standard virus replication were obtained by sequential passages of virus in suckling mouse brain. Characterization of viral RNAs in these stocks showed the presence of a heterogeneous population of defective RNA molecules derived from the L genomic segment, in both nucleocapsid (NC) and messenger RNAs, suggesting that these molecules could be replicated, assembled, and transcribed. Subgenomic RNAs from the L segment but not from the S or M segments were found in cells infected with these stocks. Defective RNA molecules interfered with virus replication and retained 5' and 3' genomic termini. Nucleotide sequence analysis of some cloned defective interfering (DI) RNAs revealed they contained one or more internal deletions reducing their length to 7-13% of the full-length L segment. An identical sequence motif, of variable length, was found at both terminal sites of the RNA junction on standard L sequences. This motif was retained only in one copy in the subgenomic RNA. These results are consistent with the generation of TOS virus DI particles in vivo and suggest that the defective genomic RNAs could be generated by polymerase jumping from a sequence to an identical one spatially closed because of the RNA structure.

A stochastic model for the sigmoidal behaviour of cooperative biological systems.

A stochastic model for cooperative transitions in biological systems based on a Markov chain is proposed. This model requires only two parameters, the mean probability, p, and the coupling capacity, Deltap, which measure the probability of forming a new weak bond depending on the number of similar bonds already formed and it is also responsible for the transition. In this paper we show how the model works for a large number of identical molecules and how it can be useful for studying the noise around the centre of the transition where, increasing the degree of cooperativity, i.e. the number n in the well-known Hill equation, the width of the noise increases along with its fractal dimension. A simple relationship between the degree of cooperativity and the parameter Deltap is proposed, suggesting that the cooperativity of real biological transitions is related to the coupling capacity Deltap of the present model.

Toscana virus genomic L segment: molecular cloning, coding strategy and amino acid sequence in comparison with other negative strand RNA viruses.

The complete nucleotide sequence of Toscana (TOS) virus (Bunyaviridae, Phlebovirus) L segment was determined. The L segment is 6404 nucleotides long, containing a single open reading frame (ORF) in the viral complementary sense coding for a protein of 2095 amino acids that, as in the case of negative strand RNA viruses, could be part of the RNA polymerase of TOS virus. This ORF is expressed by a messenger RNA (mRNA) as long as the genomic segment. Like the mRNAs expressed by the genomic segments of the other Bunyaviruses, the L mRNA has non-templated sequences at the 5' end. The comparison of TOS L protein sequence with the corresponding sequences of other negative strand RNA viruses showed a very high homology only with the Rift Valley Fever (RVF) virus. The residues conserved between the two proteins are mainly concentrated in the central region and contain three DD motifs proposed by Argos (1988) to be functional domains of DNA and RNA polymerases. The complete sequence of the Toscana virus L genomic segment has been deposited in the EMBL library with the accession number X68414.

Analysis of 3' and 5' ends of N and NSs messenger RNAs of Toscana Phlebovirus.

The 5' and 3' ends of N and NSs mRNAs, transcribed from the S segment of Toscana Phlebovirus, were analyzed by oligonucleotide primer extension and S1 nuclease mapping procedures. The results showed that both mRNAs acquired, at their 5' end, approximately 9-15 nucleotides not present in the viral template, suggesting an initiation transcription mechanism similar to the one described for influenza virus. Furthermore, the 3' ends of the two mRNAs were located in a sequence motif conserved in the S segment of two other Phleboviruses, the Rift Valley Fever and Sandfly Fever Sicilian viruses. This finding suggests the possible involvement of this sequence in the mechanism of transcription termination.

Sequences and coding strategies of the S RNAs of Toscana and Rift Valley fever viruses compared to those of Punta Toro, Sicilian Sandfly fever, and Uukuniemi viruses.

The sequences and coding strategies of the S RNAs of two viruses, Toscana (TOS) and the M12 derivative of Rift Valley fever ZH-548 (RVF, Phlebovirus genus, Bunyaviridae) have been determined from cDNA clones and compared to the previously published sequences of Punta Toro (PT), Sandfly fever Sicilian (SFS), and Uukuniemi (UUK) viruses. All five viruses exhibit an ambisense coding strategy for their small (S) RNA species, i.e., one gene product (the NSs protein) is encoded in the 5' half of the viral RNA, a second (the N protein) is encoded in the sequence complementary to the 3' half. The terminal nucleotides of the S RNAs of the five viruses are comparable through 13-14 residues. The 3' and 5' ends of these S RNAs have inverted complementary compositions. Three phleboviruses (TOS, SFS, and RVFV) exhibit comparable G-rich, centrally located intergenic sequences, albeit of different lengths. These sequences have a number of similar motifs at, or immediately following, the end of the coding regions, motifs that may be involved in their S mRNA transcription termination processes. The other two viruses (UUK, PT) have AT-rich intergenic sequences that have the potential to form secondary structure. They lack the G-rich sequences or particular sequence motifs recognized in the other three virus RNAs. The deduced sizes of the TOS and RVFV N proteins are 27,704 and 27,430 kDa (respectively). Their NSS proteins are 36,677 and 29,903 kDa (respectively). When aligned, the deduced sequences of the N proteins of the five viruses exhibit homologies ranging from 54 to 30%. The order of homology to RVFV N protein is PT greater than TOS greater than SFS greater than UUK; to TOS N protein it is PT greater than or equal to RVF greater than SFS greater than UUK. The sequences of the NSS proteins are less similar, with values ranging from 30 to less than 17%. The order of homology to RVFV NSS is SFS greater than PT greater than TOS greater than UUK. Due to these more distant relationships, the homologies to TOS NSS protein are less clear.

Urinary polyamine excretion in man. II. Influence of menstrual cycle.

24 hours urinary excretion of putrescine, spermidine and spermine was analysed at various phases of the menstrual cycle in 10 regularly menstruating women aged 20-40 years. After determining the ovulation time, by means of the basal temperature, the menstrual cycle was divided into five stages. The urinary excretion of putrescine and spermidine appears more marked during the follicular phase. During the luteal phase spermine excretion levels may be as much as 50 times higher than those found during the other stages of the cycle. Mean values show a wide fluctuation, which depends upon the individual. Moreover, the mean values of urinary excretion of di- and polyamines of 3 menstrual cycles in a 37 year old subject, showed little variation in this person. These results suggest that a relationship exists between the phases of the menstrual cycle and the variations in urinary levels of di- and polyamines.