Spatial organization of multi-enzyme biocatalytic cascades.

Industrial biocatalysis is an economically attractive option for the production of valuable chemicals. Our repertoire of cheap building blocks and commodity target molecules is vastly enhanced by multi-enzyme biocatalytic cascades. In order to achieve suitable titers in complex novel biocatalytic schemes, spatial organization may become necessary to overcome barriers caused by slow or inhibited enzymes as well as instability of biocatalysts. A number of spatial organization strategies are currently available, which could be integrated in the design of complex cascades. These include fusion proteins, immobilization on solid supports, multi-dimensional scaffolding, and encapsulation within vessels. This review article highlights recent advances in cascade biocatalysis, discusses the role of spatial organization in reaction kinetics, and presents some of the currently employed strategies for spatial organization of multi-enzyme cascades.

Feeding by Leucopis argenticollis and Leucopis piniperda (Diptera: Chamaemyiidae) from the western USA on Adelges tsugae (Hemiptera: Adelgidae) in the eastern USA.

Leucopis argenticollis (Zetterstedt) and Leucopis piniperda (Malloch) are known to feed on the lineage of Adelges tsugae Annand that is native to western North America, but it is not known if they will survive on the lineage that was introduced from Japan to the eastern USA. In 2014, western Leucopis spp. larvae were brought to the laboratory and placed on A. tsugae collected in either Washington (North American A. tsugae lineage) or Connecticut (Japanese lineage). There were no significant differences in survival or developmental times between flies reared on the two different adelgid lineages. In 2015 and 2016, western Leucopis spp. adults were released at two different densities onto enclosed branches of A. tsugae infested eastern hemlock (Tsuga canadensis (L.) Carr.) in Tennessee and New York. Cages were recovered and their contents examined 4 weeks after release at each location. Leucopis spp. larvae and puparia of the F1 generation were recovered at both release locations and adults of the F1 generation were collected at the Tennessee location. The number of Leucopis spp. offspring collected increased with increasing adelgid density, but did not differ by the number of adult flies released. Flies recovered from cages and flies collected from the source colony were identified as L.argenticollis and L. piniperda using DNA barcoding. These results demonstrate that Leucopis spp. from the Pacific Northwest are capable of feeding and developing to the adult stage on A. tsugae in the eastern USA and they are able to tolerate environmental conditions during late spring and early summer at the southern and northern extent of the area invaded by A. tsugae in the eastern USA.

Seasonal phenology and abundance of Leucopis argenticollis, Leucopis piniperda (Diptera: Chamaemyiidae), Laricobius nigrinus (Coleoptera: Deridontidae) and Adelges tsugae (Hemiptera: Adelgidae) in the Pacific Northwest USA.

Adelges tsugae infested western hemlock trees were sampled periodically for 1 year at two locations in Oregon and Washington to compare the phenology and abundance of three associated predators (Leucopis argenticollis, Leucopis piniperda, and Laricobius nigrinus) and their host. On each sample date, two 3-10 cm long terminal twigs were collected from each tree and brought to the laboratory to count all life stages of A. tsugae and the three predators. Peak larval abundance of Leucopis spp. and La. nigrinus coincided with the presence of A. tsugae adults and eggs. Leucopis spp. larvae were present for a much longer period of time than were La. nigrinus larvae. Furthermore, Leucopis spp. larvae were present during both the progrediens and sistens egg stages, while La. nigrinus larvae were only present during the progrediens egg stage. Overall, we collected 2.3-3.5 times more Leucopis spp. of all life stages than La. nigrinus. These results support the continued study of Leucopis spp. from the Pacific Northwest as biological control agents for A. tsugae in the Eastern USA.

Cadmium inhibits ABCG2 transporter function in BeWo choriocarcinoma cells and MCF-7 cells overexpressing ABCG2.

Heavy metals such as cadmium, lead and methylmercury are known to be neurotoxic to developing fetus. ABCG2 which is an efflux transporter located in the maternal facing membranes of human placenta protects fetus from xenobiotics by transferring compounds from syncytiotrophoblast to maternal circulation. The aim of this study was to clarify whether heavy metal compounds (CdCl(2), PbCl(2) and MeHgCl) affect the expression and function of ABCG2 transporter in human placental BeWo choriocarcinoma cells. The expression of ABCG2 was determined by immunoblotting and RT-PCR. The functional activity of ABCG2 was evaluated by measuring the efflux of two known ABCG2 substrates: fluorescent mitoxantrone and (14)C-labeled food carcinogen PhIP. According to MTT assay all compounds were cytotoxic as expected (MeHgCl > CdCl(2) > PbCl(2)). CdCl(2) inhibited the efflux of mitoxantrone and (14)C-PhIP suggesting inhibition of ABCG2 transporter function. PbCl(2) had no effect on mitoxantrone efflux. Because of high toxicity, the inhibitory potency of MeHgCl was not tested. According to protein data these heavy metals did not affect ABCG2 transporter protein expression. Also, the expression of ABCC1, ABCC2 or ABCG2 mRNA were not affected by heavy metals. In conclusion, although the studied metal salts did not affect mRNA or protein expression of ABCG2, CdCl(2) inhibited its function. Further studies to evaluate whether this leads to elevated placental transfer of ABCG2 substrates are needed.

Predators associated with the hemlock woolly adelgid (Hemiptera: Adelgidae) in the Pacific Northwest.

The hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is causing widespread mortality of eastern hemlock, Tsuga canadensis L. Carrière, in the eastern United States. In western North America, feeding by A. tsugae results in negligible damage to western hemlock, Tsuga heterophylla (Raf.) Sargent. Host tolerance and presence of endemic predators may be contributing to the relatively low levels of injury to T. heterophylla caused by A. tsugae. Field surveys of the predator community associated with A. tsugae infestations on 116 T. heterophylla at 16 sites in Oregon and Washington were conducted every 4-6 wk from March 2005 through November 2006. Fourteen uninfested T. heterophylla were also surveyed across 5 of the 16 sites. Each sample tree was assigned an A. tsugae population score ranging from 0 to 3. Predators collected from A. tsugae-infested T. heterophylla represent 55 species in 14 families, listed in order of abundance: Derodontidae, Chamaemyiidae, Hemerobiidae, Coccinellidae, Cantharidae, Reduviidae, Miridae, Syrphidae, Chrysopidae, Coniopterygidae, Staphylinidae, Anthocoridae, Nabidae, and Raphidiidae. Laricobius nigrinus Fender (Coleoptera: Derodontidae), Leucopis argenticollis Zetterstedt (Diptera: Chamaemyiidae), and Leucopis atrifacies (Aldrich) (Chamaemyiidae) were the most abundant predators; together comprising 59% of predator specimens recovered. Relationships among predators and A. tsugae were determined through community structure analysis. The abundances of Laricobius spp. larvae, L. nigrinus adults, Leucopis spp. larvae, and L. argenticollis adults were found to be positively correlated to A. tsugae population score. Predators were most abundant when the two generations of A. tsugae eggs were present. L. argenticollis and L. atrifacies were reared on A. tsugae in the laboratory, and host records show them to feed exclusively on Adelgidae.

High release rate 3-methylcyclohex-2-en-1-one dispensers prevent Douglas-fir beetle (Coleoptera: Curculionidae) infestation of live Douglas-fir.

The Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins (Coleoptera: Curculionidae), antiaggregation pheromone, 3-methylcyclohex-2-en-1-one (MCH), has been used by natural resource managers and landowners to protect high-value, high-risk trees from Douglas-fir beetle infestation throughout the western United States since 2000. Labor is a major portion of the cost of MCH treatments. MCH is applied by walking through treatment areas and stapling the formulated pheromone in bubble capsules to trees and other objects on a regular grid pattern. Reducing the number of MCH release points and increasing the distance between them could significantly reduce labor costs, particularly in areas with steep terrain or large volumes of woody debris that could impede the movement of applicators. This study compared the standard MCH application method with a method releasing MCH at a 3 times higher rate and placed at three times fewer release points per unit area. Treatments were applied to 2-ha plots simulating an operational application. Aggregation pheromone-baited traps were placed at plot centers to ensure that dispersing adult beetles would be present on all plots. Both MCH treatments were equally effective at preventing the infestation of live Douglas-fir, Pseudotsugae menziesii (Mirbel) Franco, trees (> or = 30 cm diameter at breast height). These results confirm that MCH formulated to release at three times the current standard rate and placed at 3 times fewer points per unit area can effectively prevent the infestation of live Douglas-fir. The new treatment will significantly reduce the labor cost of MCH applications making them feasible for areas that may have previously been marginal economically.

Parasitoids reared from predators of hemlock woolly adelgid (Hemiptera: Adelgidae), and the hymenopterous parasitoid community on western hemlock in the Pacific Northwest.

In western North America, infestations of the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), are common on orchard, ornamental, and roadside western hemlock, Tsuga heterophylla (Raf.) Sargent. However, these infestations rarely cause T. heterophylla mortality. Host tolerance and presence of endemic predators may be contributing to the relatively low levels of injury to T. heterophylla caused by A. tsugae. Field surveys of the arthropod community associated with A. tsugae infestations on 116 T. heterophylla at 16 sites in Oregon and Washington were conducted every 4-6 wk from January 2005 through November 2006. Fourteen uninfested T. heterophylla were also surveyed across 5 of the 16 sites. Immature A. tsugae predators collected in the field were brought to the laboratory for rearing. Eight species of hymenopterous parasitoids were reared from pupae of predators of A. tsugae in the laboratory. Two Pachyneuron spp. (Pteromalidae) and a Melanips sp. (Figitidae) were reared from Leucopis spp. (Diptera: Chamaemyiidae) puparia. Syrphoctonus pallipes (Gravenhorst) (Ichneumonidae), Woldstedtius flavolineatus (Gravenhorst) (Ichneumonidae), Syrphophagus sp. (Encyrtidae), and Pachyneuron albutius Walker were reared from Syrphidae (Diptera) puparia. A Helorus sp. (Heloridae) was reared from a Chrysoperla sp. (Neuroptera: Chrysopidae) cocoon. Laboratory rearing did not show any direct association between parasitoids and A. tsugae. In the field survey, a total of 509 adult parasitic Hymenoptera representing 19 families and at least 57 genera were collected from T. heterophylla. Nonparametric analysis of community structure showed Pachyneuron spp. were strongly correlated to abundance of their Leucopis spp. hosts and to A. tsugae population score in the field. The possible impact of parasitism on Leucopis spp., potential A. tsugae biological control candidates for the eastern United States, is discussed.

Frequent gain of the human telomerase gene TERC at 3q26 in cervical adenocarcinomas.

The level of genomic amplification of the human telomerase gene TERC, which maps to chromosome band 3q26, was determined in primary cervical adenocarcinomas. Interphase nuclei prepared from archival material of 12 primary cervical adenocarcinomas, eight of which were human papillomavirus positive, were hybridised with a triple colour probe set specific for centromeres of chromosomes 3 and 7 and the TERC gene. We observed high proportions of nuclei with increased absolute copy numbers for TERC in all tumours (mean 3.3; range 2.3-5.2). Amplification of the human telomerase gene TERC is a consistent aberration in cervical adenocarcinomas. Therefore, application of our probe set may provide an objective genetic test for the assessment of glandular cells in Pap smears and hence for the diagnosis of cervical adenocarcinomas.

Detection of adeno-associated virus type 2 genome in cervical carcinoma.

Adeno-associated virus (AAV) can impair the replication of other viruses. Adeno-associated virus seroprevalences have been reported to be lower among women with cervical cancer. In-vitro, AAV can interfere with the production of human papillomavirus virions. Adeno-associated virus-2 DNA has also been detected in cervical cancer tissue, although not consistently. To evaluate the role of AAV infection in relation to invasive cervical cancer, we performed a nested case-control study within a retrospectively followed population-based cohort. A total of 104 women who developed invasive cervical cancer on average 5.6 years of follow-up (range: 0.5 months-26.2 years) and 104 matched control-women who did not develop cervical cancer during the same follow-up time were tested for AAV and human papillomavirus by polymerase chain reaction. At baseline, two (2%) case-women and three (3%) control-women were positive for AAV-2 DNA. At the time of cancer diagnosis, 12 (12%) case-women and 3 (3%) matched control-women were positive for AAV-2 DNA. Persisting AAV infection was not evident. In conclusion, AAV-2 DNA was present in a low proportion of cervical cancers and we found no evidence that the presence of AAV in cervical smears of healthy women would be associated with reduced risk of cervical cancer.

Parallel cyclin E and cyclin A expression in neoplastic lesions of the uterine cervix.

Cyclin E levels are high during late G1 and early S-phase in normal cells. The cyclin E expression over the cell cycle in tumours is not fully known. The impact on patient outcome by high cyclin E levels during other parts of the cell cycle than late G1- and early S-phase is unknown. We set out to study the expression of cyclin E over the cell cycle in cervical carcinomas. Using immunofluorescence staining of cyclin A, digital microscopy, and digital image analysis, we determined which cells in a tissue section that were in S- or G2-phase. M-phase cells were detected by morphology. By simultaneously staining for cyclin E, we investigated the variation in cyclin E levels over the cell cycle in cervical carcinoma lesions. In a case-control study, in which each deceased patient was matched with a patient still alive and well after >5 years of follow-up, we found that the deceased patients had a considerably higher fraction of cyclin A-positive cells staining for cyclin E than the survivors (n = 36). We conclude that parallel cyclin E and cyclin A expression is an indicator for poor outcome in cervical carcinomas. In addition, we investigated the expression pattern of cyclin E and cyclin A in consecutive biopsy samples from cervical carcinomas at different stages, as well as in human papillomavirus positive or negative adenocarcinomas in order to further study the cyclin E and cyclin A expression pattern in neoplastic lesions of the uterine cervix.

The clinicopathologic significance of laminin-5 gamma2 chain expression in cervical squamous carcinoma and adenocarcinoma.

Carcinoma of the uterine cervix is one of the most prevalent malignancies among women in developing countries and the third most common type worldwide. Squamous cell carcinoma predominates in the cervix uteri, while adenocarcinoma and adenosquamous carcinomas represent about 10-15% of all cervical cancers. Many studies have confirmed that the human papillomavirus (HPV) is the most important etiologic factor in the development of cervical cancer. The aim of our study was to investigate the expression of the laminin-5 gamma2 chain in primary malignancies of the cervix uteri and to focus on the clinicopathologic significance of the expression of the laminin-5 gamma2 chain in cervical squamous carcinoma and adenocarcinoma with respect to age and survival of the patients. The study consisted of a total of 89 cases of invasive cervical cancer (54 squamous carcinomas and 35 adenocarcinomas). The laminin-5 gamma2 chain was found in 80% of all the squamous carcinoma and in 66% of cervical adenocarcinoma. There was no correlation of the high expression of laminin-5 with survival. The univariate analysis in squamous cell carcinoma showed that factors such as the stage of the disease and positive lymph nodes had an impact on the survival of the patients, whereas in the multivariate analysis, only age at diagnosis was an independent prognostic factor. However, in cases with cervical adenocarcinoma, only the stage of the disease was an independent prognostic factor. There was no difference between HPV-positive and HPV-negative tumors concerning the high expression of laminin-5 gamma2 chain. Our results indicate that the majority of the primary cervical tumors, especially squamous cell carcinoma, showed expression of laminin-5 gamma2 chain immunoreactivity. Independent prognostic values for the survival of the patients were age and stage of the disease.

Tumor necrosis factor A and MHC class I chain related gene A (MIC-A) polymorphisms in Swedish patients with cervical cancer.

Human papillomaviruses type 16 and 18 are the major cause of cervical cancer. However, genetic factors contribute to the propensity of persistent HPV infection and cervical carcinoma. Allelic variants of the human leukocyte genes have shown to be associated with cervical neoplasia. The strongest associations have been found with the genes in the HLA class II region. The aim of this study was to analyze the association of two non-HLA class II markers with invasive cervical cancer. Microsatellite polymorphism of the TNFA gene located in the class III region and a short tandem repeat polymorphism of the MICA gene located in the centromeric end of the HLA class I region were analyzed. Eighty-five patients and 120 matched control individuals from a population-based cohort from Northern Sweden participated in this nested case-control study. MICA was not associated with cervical carcinoma. TNFa-11 frequency was increased in the HPV18 DNA positive patients (OR = 2.84, p = 0.0481, CI = 1.04-7.78, pc = NS). TNFa-11 was not associated with susceptibility to HPV16 infection, but it increased the risk for cervical cancer with the HLA DQ6 (DQA 1*0102-DQB 1*0602) haplotype. Our findings indicate that the association of TNFA with cervical cancer is different with CIN. The extended HLA DQ6-TNFa-11 haplotype is increasing the risk for development of cervical cancer significantly (OR = 3.08, p = 0.0104, CI = 1.30-7.31).

Effect of host tree seasonal phenology on substrate suitability for the pine engraver (Coleoptera: Scolytidae): implications for population dynamics and enemy free space.

This study evaluated the effects of seasonal phenology on the substrate quality of susceptible hosts to the pine engraver, Ips pini (Say). We also determined the effects of the duration and method of storage on host quality for purposes of laboratory rearing. Live red pine trees were felled at various times during the season, and I. pini adults from a laboratory colony were established on the logs. Subsamples of logs were stored for various intervals, and then provided to beetles. Subsamples of stored logs were waxed at both ends to prevent water loss before being submitted to the same assays. Suitability of red pine phloem tissue in susceptible hosts declined for I. pini throughout the growing season. As the season progressed, the number of beetle progeny that emerged from colonized hosts dropped substantially. This decline was associated with simultaneous reductions in phloem moisture content. Reduction in host suitability may partially offset any advantage I. pini may gain from colonizing trees after the major predators have become less abundant. Bark beetle brood production decreased significantly with length of storage, regardless of the month of tree felling or the method of storing. Implications for bark beetle population dynamics and laboratory rearing systems are discussed.

Human papillomavirus infection, risk for subsequent development of cervical neoplasia and associated population attributable fraction.

BACKGROUND: Human papillomavirus (HPV) is the major cause of cervical neoplasia but estimates of the population attributable fraction (PAR%), of HPV vary. PAR% has not been derived from longitudinal studies although assessment of HPV exposure prior to the neoplasia diagnosis should increase validity of such estimates. AIMS: Systematic review and meta-analysis of longitudinal studies on HPV associated relative risk (RR) for and PAR% of HPV16 in cervical neoplasia. METHODS: Pertinent data from longitudinal studies was made available through Medline and substituted by various hand searches. HPV associated weighted mean RR, with 95% confidence interval (CI) of cervical neoplasia, and the PAR% of HPV16 in cervical carcinoma were estimated both for unselected and low HPV prevalence populations. RESULTS: HPV associated RR of cervical carcinoma in PCR-based studies was 17 (95% CI 8.2-33). HPV16 associated RRs in seroepidemiological studies were 3.3 (95% CI 2.2-4.9) for the unselected population, HPV16 seroprevalence 11.0%, and 12.5 (95% CI 5.5-29) for a population with low HPV16 seroprevalence of 5.3%. Corresponding PAR% estimates of HPV16 were 27 and 44%, respectively. CONCLUSION: Protective vaccination against HPV16 infection would prevent up to 44% of cervical carcinoma.

HIV-1 in placentas of untreated HIV-1-infected women in relation to viral transmission, infectious HIV-1 and RNA load in plasma.

The presence of HIV in the placenta was analysed in relation to virological and immunological factors and vertical transmission of HIV in 39 pregnancies between 1989 and 1993 among 37 HIV-1-infected women without zidovudine prophylaxis. HIV-1 was detected in 12 of 37 (31%) placentas by immunohistochemistry and in 3 of 18 by PCR. Altogether 14/39 (36%) placentas bore evidence of HIV-1 infection, although there was no relation with the outcome of HIV infection in the child. Neither was there a relation between placental infection and either CD4 cell counts or HIV-1 RNA levels. However, HIV-1 was isolated from plasma in 20 of 39 (50%) pregnancies, which was inversely related to the presence of HIV in the placenta. When HIV-1 was identified in the placenta, HIV-1 was isolated from plasma in 3/14 (21%) pregnancies, vs 17/25 (68%) when it was not (p = 0.01), with a relative risk of having a placenta positive for HIV of 3.9 in pregnancies with a negative plasma HIV isolation. This inverse relation may point to differences in tropism between HIV-1 in placenta and plasma. The results show that the placental barrier prevents HIV transmission, irrespective of whether HIV enters the placenta or not.

Serologic evidence of Puumala virus infection in wild moose in northern Sweden.

Puumala (PUU) virus is the causative agent of nephropathia epidemica, the Scandinavian form of hemorrhagic fever with renal syndrome. The infection is acquired by airborne transmission of PUU virus from its rodent reservoir, the bank vole. Besides serologic data indicating that the virus may spread also to heterologous rodents, there is little information on the susceptibility of wild living animals to PUU virus. We studied the occurrence of antibodies to PUU virus in serum samples from 427 wild-living moose, of which 260 originated from the PUU virus-endemic northern and central parts of Sweden and 167 originated from the southern, nonendemic part of Sweden. Samples from 5 animals showed reactivity in an ELISA for recombinant PUU virus nucleocapsid protein, an immunofluorescent assay, and a neutralization test. These 5 animals all originated from the PUU virus-endemic northern part of Sweden. In conclusion, 5 of 260 moose from the endemic region showed convincing serologic evidence of past PUU virus infection. The seroprevalence was low, suggesting that the moose is subjected to endstage infection rather than being part of an enzootic transmission cycle.

Seroepidemiology of human papillomavirus type 73: a sexually transmitted low-risk virus.

Human papillomavirus type 73 (HPV 73) has been detected in some invasive cervical cancers and has been cloned from a squamous-cell carcinoma of the esophagus, but the epidemiology of this infection and its associated risk of cancer is unknown. We investigated the seroepidemiology of this virus using virus-like particles. The IgG response to HPV 73 appeared to be HPV type-specific, since a comparison of HPV 73 antibody levels before and after infection with HPV 6, 11, 16, 18 or 33 found no evidence of cross-induction of HPV 73 antibodies and since there was little correlation between the antibody levels to HPV 73 and the other 5 investigated HPV types. In both a cross-sectional serosurvey that included 274 women and a 7-year follow-up study that enrolled 98 women, HPV 73 seropositivity was found to be strongly dependent on the number of lifetime sexual partners [OR for > 4 vs. 0 to 1 partners: 6.0 (95%CI: 1.4-53.6) and 7.9 (95% CI: 2.8-28.3), respectively]. Finally, the risk for HPV 73 seropositive women to develop CIN was investigated in a prospective study nested in a cohort of 15,234 Swedish women. The population-based HPV 73 seroprevalence in Sweden was 14%. No excess risk for CIN was found (OR: 0.77). We conclude that HPV 73 is a mainly sexually transmitted, probably mostly transient, infection that does not confer any measurably increased risk for CIN development.

Type-specific persistence of human papillomavirus DNA before the development of invasive cervical cancer.

BACKGROUND: Infection with the human papillomavirus (HPV) has been established as a cause of cervical cancer, but the association between a positive test for HPV DNA and the risk of the subsequent development of invasive cervical cancer is unknown. METHODS: In a study of women who participated in a population-based screening program for cancer of the cervix in Sweden from 1969 to 1995, we compared the proportion of normal cervical smears (Pap smears) that were positive for HPV DNA among 118 women in whom invasive cervical cancer developed an average of 5.6 years later (range, 0.5 month to 26.2 years) with the proportion of HPV DNA-positive smears from 118 women who remained healthy during a similar length of follow-up (controls). The control women were matched for age to the women with cancer, and they had had two normal Pap smears obtained at time points that were similar to the times of the baseline smear and the diagnosis of cancer confirmed by biopsy in the women with cancer. RESULTS: At baseline, 35 of the women with cancer (30 percent) and 3 of the control women (3 percent) were positive for HPV DNA (odds ratio, 16.4; 95 percent confidence interval, 4.4 to 75.1). At the time of diagnosis, 80 of the 104 women with cancer for whom tissue samples were available (77 percent) and 4 of the 104 matched control women (4 percent) were positive for HPV DNA. The HPV DNA type was the same in the base-line smear and the biopsy specimen in all of the women with cancer in whom HPV DNA was detected at base line. None of the control women had the same type of HPV in both smears. CONCLUSIONS: A single positive finding of HPV DNA in a Pap smear confers an increased risk of future invasive cervical cancer that is positive for the same type of virus as identified earlier.

Sexual behaviour and papillomavirus exposure in cervical intraepithelial neoplasia: a population-based case-control study.

Sexual history is an established risk determinant for cervical neoplasia. It is not clear if human papillomavirus (HPV) exposure entirely explains the sexual behaviour-related risk or if other sexually transmitted agents may act as cofactors for HPV in carcinogenesis. The aim of this study was to elucidate whether HPV exposure or HPV persistence explains the sexual history-related risk of high-grade cervical intraepithelial neoplasia (CIN) using a population-based case-control study of most of the 254 women referred to colposcopy in the Vasterbotten county in Sweden because of an abnormal cervical smear during October 1993 to December 1995 and 320 age-matched women from the general population. The women were interviewed for sexual history and tested for presence of serum antibodies to HPV-16, -18 and -33 as well as for presence of HPV DNA in cervical brush samples. HPV-16, -18 and -33 seropositivity was specific for the corresponding type of HPV DNA, dependent on the lifetime sexual history and associated with a two- to threefold increased risk of CIN 3. There was no sexual history-related risk of CIN among HPV-seropositive women and adjustment for HPV DNA presence explained the sexual history-related risk of CIN. In conclusion, HPV exposure appeared to explain the sexual history-related risk of high-grade CIN.

Teaching oncology and cancer care to general practice trainees in Sweden: a two-year prospective, randomized study.

OBJECTIVE: To improve general practice (GP) trainees' knowledge of and attitudes towards oncology and their management of cancer patients. METHOD: A prospective study of 33 GP trainees who, after a first assessment, were randomized either to attend a two-year cancer course (n = 17) or to a control group (n = 16). Both groups were tested at the beginning (pretest) and end (post-test) of the two years. The maximum possible score was 76. All tests were corrected blindly by an oncologist and a general practitioner. RESULTS: The intervention group showed significant post-test-pretest improvements in the domains "knowledge" (mean difference 2.6, 95% CI 1.3-3.8) and "attitudes" (mean difference 2.9, 95% CI 0.8-5.0), but not in "patient management" (mean difference 0.3, 95% CI -0.6-1.2). There was no significant change in the test scores of the controls. The total mean (post-test-pretest) differences were 8.3 (95% CI 4.9-11.6 for the intervention group and -1.4 (95% CI -4.1-1.3) for the controls. CONCLUSION: A low-intensity two-year cancer course improved the knowledge and attitudes of GP trainees. Patient management, however, was not improved and may be more suited for hospital training. The current five-year specific training in general practice in Sweden seemed to be of limited value in the field of oncology. Thus, there is a need for further development of educational tools for cancer training of GP trainees, at least in Sweden.