Relationship of episiotomy to perineal trauma and morbidity, sexual dysfunction, and pelvic floor relaxation

OBJECTIVE

Our purpose was to compare consequences for women of receiving versus not receiving median episiotomy early and 3 months post partum on the outcomes perineal pain, urinary and pelvic floor functioning by electromyography, and sexual functioning and to analyze the relationship between episiotomy and third- and fourth-degree tears.

STUDY DESIGN

A secondary cohort analysis was performed of participants within a randomized clinical trial, analyzed by type of perineal trauma and pain, pelvic floor, and sexual consequences of such trauma, while controlling for trial arm. The study was conducted in three university or community hospitals; 356 primiparous and 341 multiparous women were studied.

RESULTS

Early and 3-month-postpartum perineal pain was least for women who gave birth with an intact perineum. Spontaneous perineal tears were less painful than episiotomy. Sexual functioning was best for women with an intact perineum or perineal tears. Postpartum urinary and pelvic floor symptoms were similar in all perineal groups. At 3 months post partum those delivered with an intact perineum had the strongest pelvic floor musculature, those with episiotomy the weakest. Among primiparous women third- and fourth-degree tears were associated with median episiotomy (46/47). After forceps births were removed and 21 other variables potentially associated within such tears were controlled for, episiotomy was strongly associated with third- and fourth-degree tears (odds ratio +22.08, 95% confidence interval 2.84 to 171.53). Physicians using episiotomy at high rates also used other procedures, including cesarean section, more frequently.

CONCLUSION

Perineal and pelvic floor morbidity was greatest among women receiving median episiotomy versus those remaining intact or sustaining spontaneous perineal tears. Median episiotomy was causally related to third- and fourth-degree tears. Those using episiotomy at the highest rates were more likely use other interventions as well. Episiotomy use should be restricted to specified fetal-maternal indications.

A randomized trial to evaluate the risk of gastrointestinal disease due to consumption of drinking water meeting current microbiological standards

BACKGROUND

This project directly and empirically measured the level of gastrointestinal (GI) illness related to the consumption of tapwater prepared from sewage-contaminated surface waters and meeting current water quality criteria.

METHODS

A randomized intervention trial was carried out; 299 eligible households were supplied with domestic water filters (reverse-osmosis) that eliminate microbial and chemical contaminants from their water, and 307 households were left with their usual tapwater without a filter. The GI symptomatology was evaluated by means of a family health diary maintained prospectively by all study families over a 15-month period.

RESULTS

The estimated annual incidence of GI illness was 0.76 among tapwater drinkers compared with 0.50 among filtered water drinkers (p less than 0.01). These findings were consistently observed in all population subgroups.

CONCLUSION

It is estimated that 35% of the reported GI illnesses among the tapwater drinkers were water-related and preventable. Our results raise questions about the adequacy of current standards of drinking water quality to prevent water-borne endemic gastrointestinal illness.

Clostridium perfringens and somatic coliphages as indicators of the efficiency of drinking water treatment for viruses and protozoan cysts

To find the most suitable indicator of viral and parasitic contamination of drinking water, large-volume samples were collected and analyzed for the presence of pathogens (cultivable human enteric viruses, Giardia lamblia cysts, and Cryptosporidium oocysts) and potential indicators (somatic and male-specific coliphages, Clostridium perfringens). The samples were obtained from three water treatment plants by using conventional or better treatments (ozonation, biological filtration). All samples of river water contained the microorganisms sought, and only C. perfringens counts were correlated with human enteric viruses, cysts, or oocysts. For settled and filtered water samples, all indicators were statistically correlated with human enteric viruses but not with cysts or oocysts. By using multiple regression, the somatic coliphage counts were the only explanatory variable for the human enteric virus counts in settled water, while in filtered water samples it was C. perfringens counts. Finished water samples of 1,000 liters each were free of all microorganisms, except for a single sample that contained low levels of cysts and oocysts of undetermined viability. Three of nine finished water samples of 20,000 liters each revealed residual levels of somatic coliphages at 0.03, 0.10, and 0.26 per 100 liters. Measured virus removal was more than 4 to 5 log10, and cyst removal was more than 4 log10. Coliphage and C. perfringens counts suggested that the total removal and inactivation was more than 7 log10 viable microorganisms. C. perfringens counts appear to be the most suitable indicator for the inactivation and removal of viruses in drinking water treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

High rates of HIV infection among injection drug users participating in needle exchange programs in Montreal: results of a cohort study

Needle exchange programs (NEPs) are designed to prevent human immunodeficiency virus (HIV) transmission among injection drug users. Although most studies report beneficial effects in terms of behavior modification, a direct assessment of the effectiveness of NEPs in preventing HIV infection has been lacking. A cohort study was conducted to assess the association between risk behaviors and HIV seroprevalence and seroincidence among injection drug users in Montreal, Canada. The association between NEP use and HIV infection was examined in three risk assessment scenarios using intensive covariate adjustment for empirical confounders: a cross-sectional analysis of NEP use at entry as a determinant of seroprevalence, a cohort analysis of NEP use at entry as a predictor of subsequent seroconversion, and a nested case-control analysis of NEP participation during follow-up as a predictor of seroconversion. From September 1988 to January 1995, 1,599 subjects were enrolled with a baseline seroprevalence of 10.7%. The mean follow-up period was 21.7 months. The adjusted odds ratio for HIV seroprevalence in injection drug users reporting recent NEP use was 2.2 (95% confidence interval 1.5-3.2). In the cohort study, there were 89 incident cases of HIV infection with a cumulative probability of HIV seroconversion of 33% for NEP users and 13% for nonusers (p < 0.0001). In the nested case-control study, consistent NEP use was associated with HIV seroconversion during follow-up (odds ratio = 10.5, 95% confidence interval 2.7-41.0). Risk elevations for HIV infection associated with NEP attendance were substantial and consistent in all three risk assessment scenarios in our cohort of injection drug users, despite extensive adjustment for confounders. In summary, in Montreal, NEP users appear to have higher seroconversion rates then NEP nonusers.

Prostate cancer and use of nonsteroidal anti-inflammatory drugs: systematic review and meta-analysis

Animal and laboratory studies suggest that regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce prostate cancer risk. To assess this association, we conducted a systematic review and meta-analysis of observational studies published before January 2003. We derived summary odds ratios (ORs) using both fixed and random effects models and performed subgroup analyses to explore the possible sources of heterogeneity between combined studies. We identified 12 reports (five retrospective and seven prospective studies). Most studies of aspirin use reported inverse associations, but only two were statistically significant. The summary OR for the association between aspirin use and prostate cancer was 0.9 (95% confidence interval: 0.82-0.99; test of homogeneity P=0.32), and varied from 1.0 for retrospective studies to 0.85 for prospective studies. Studies that measured exposure to a mixture of NSAIDs were less consistent. These results indicate an inverse association between aspirin use and prostate cancer risk. The current epidemiological evidence and, in particular, the strong and consistent laboratory evidence underline the need for additional epidemiological studies to confirm the direction and magnitude of the association.

Associations between cigarette smoking and each of 21 types of cancer: a multi-site case-control study

BACKGROUND

Although the effects of cigarette smoking on cancer risk have been well documented, there remain several outstanding issues to be clarified, including the determination of which types of cancer are associated with smoking and estimation of the magnitude of the effect of smoking on different types of cancer. A further issue is whether the effects seen elsewhere can be demonstrated in Canada, where tobacco products differ somewhat from those in other countries.

METHODS

A case-control study was undertaken in Montreal to investigate the associations between a large number of environmental and occupational exposures on the one hand, and several types of cancer on the other. Between 1979 and 1985, interviews were carried out with incident male cases of 21 types of cancer, including 15 anatomical sites and six histological subtypes. The interview was designed to obtain detailed information on smoking histories, job histories, and other potential confounders. Altogether, 3730 cancer patients and 533 population controls were interviewed. For each type of cancer analysed, two control groups were used: population controls and cancer controls (selected from among other cancer patients). The purpose of the present analysis is to estimate the relative risk of each of 21 types of cancer in relation to smoking and to estimate the percentage of cancer cases attributable to cigarette smoking.

RESULTS

Separate analyses conducted with the two control groups produced similar results. Of the many sites of cancer examined, the following were not associated with cigarette smoking: colon, rectum, liver, prostate, kidney and skin (melanoma). Within the lymphoreticular system, there was no excess risk of Hodgkin's lymphoma, although the results for non-Hodgkin's lymphoma were weakly suggestive of an association with smoking. The following sites were clearly associated with smoking: lung (odds ratio [OR] = 12.1), bladder (OR = 2.4), oesophagus (OR = 2.4), stomach (OR = 1.7), and pancreas (OR = 1.6). Population attributable risk percentages due to smoking were 90% for lung, 53% for bladder, 54% for oesophagus, 35% for stomach, and 33% for pancreas.

CONCLUSIONS

Of the 21 types of cancer examined, the following were associated with smoking among men in Montreal: lung (including all major histological subtypes), bladder (and its main histological subtypes), oesophagus, stomach and pancreas. Smoking likely accounts for a large proportion of cancers occurring at these sites.

Antibodies against glutathione S-transferase T1 (GSTT1) in patients with de novo immune hepatitis following liver transplantation

Four patients of 283 liver-transplant recipients (1.4%) developed de novo immune-mediated hepatitis approximately 2 years after transplantation. Antibodies showing an unusual liver/kidney cytoplasmic staining pattern were detected in the sera of all four patients and one of them was used to screen a human liver cDNA expression library with the aim of identifying the antigenic target of these newly developed antibodies. After cloning and sequencing the gene, it was identified as the gene encoding the glutathion-S-transferase T1 (GSTT1), a 29-kD molecular weight protein, expressed abundantly in liver and kidney. Sera from the other three patients also contained anti-GSTT1 antibodies, two of them demonstrated by immunoblot analysis against the recombinant antigen and the other, which was negative by immunoblot, gave a positive reaction when used directly to screen the same library, suggesting it to be directed to a conformational epitope. The GSTT1 enzyme is the product of a single polymorphic gene that is absent from 20% of the Caucasian population. When we analysed the GSTT1 genotype of the four patients described above, we found that this gene is absent from all of them. Three donor paraffin embedded DNA samples were available and were shown to be positive for GSSTT1 genotype. In accordance with these results, we suggest that this form of post-transplant de novo immune hepatitis, that has been reported as autoimmune hepatitis by others, could be the result of an antigraft reaction in individuals lacking the GSTT1 phenotype, in which the immune system recognizes the GSTT1 protein as a non-self antigen, being the graft dysfunction not the result of an autoimmune reaction, but the consequence of an alo-reactive immune response.

Design and methods of the Ludwig-McGill longitudinal study of the natural history of human papillomavirus infection and cervical neoplasia in Brazil. Ludwig-McGill Study Group

This article reports on a large longitudinal study, begun in 1993, of the natural history of human papillomavirus (HPV) infection and cervical neoplasia in a population of low-income women in São Paulo, Brazil, a city with one of the highest risks worldwide for cervical cancer. Known as the Ludwig-McGill cohort study, the epidemiological investigation focuses on persistent infection with oncogenic HPV types as the precursor event leading to cervical neoplasia. The objectives of this study are to: 1) study the epidemiology of persistent cervical HPV infection in asymptomatic women, 2) investigate whether persistent HPV infection increases risk of low-grade and high-grade cervical lesions, 3) search for determinants of persistent HPV infection, 4) search for molecular variants of HPV that may be associated with an increased risk of lesions, 5) investigate whether viral burden is correlated with persistent infections and with lesion risk, 6) study the antibody response to HPV as a predictor of persistence and lesion progression, and 7) examine the role of HLA typing and codon 72 p53 gene polymorphism in mediating HPV persistence and lesion severity. The study accrued 2,528 female subjects through March 1997. Subjects were followed up every 4 months in the first year, with twice-yearly return visits to take place in subsequent years. Participants undergo a questionnaire-based interview, have a cervical specimen taken for Pap cytology and HPV testing, and have a blood sample drawn for HPV antibody testing. A cervicography is performed once in the first year and every two years thereafter. In this article we describe the design and methods of the study, provide baseline cohort characteristics, and present a preliminary assessment of the prognostic value of baseline HPV status.

Dose, efficacy and tolerability of long-term indomethacin treatment of chronic paroxysmal hemicrania and hemicrania continua

Indomethacin has consistently been proven to provide complete and sustained relief of symptoms in hemicrania continua (HC) and chronic paroxysmal hemicrania (CPH), but is not devoid of side-effects. The goal of this retrospective study is to assess the dose and side-effects of prolonged indomethacin treatment of HC and CPH. Twenty-six patients with either HC or CPH were followed during an average of 3.8 years after onset of treatment with indomethacin. Relief of symptoms occurred within 3 days of treatment, with 84 +/- 32 mg/day of indomethacin. With time, 42% of patients experienced a decrease of up to 60% in the dose of indomethacin required to maintain a pain-free state. Six (23%) patients showed adverse events, mostly gastrointestinal and relieved with ranitidine. No major side-effects were observed. These results indicate that prolonged indomethacin treatment of HC or CPH has a good safety and tolerability profile with a reduction of up to 60% in the initial dose.

The role of professional diagnostic delays in the prognosis of upper aerodigestive tract carcinoma

Despite the belief that cancer mortality can be reduced if lesions are detected, diagnosed and treated at an early stage, only one study, among a number concerning cancers of the upper aerodigestive tract (UADT), has found any relationship between such delays and prognosis for this population of cancer patients. The aim of this study was, therefore, to investigate the relationship between patient and professional diagnostic delays and patient prognosis in a group of UADT cancer patients. Patients diagnosed with squamous cell carcinoma of oral cavity sites (ICD-9 141, 143-5)oro-, naso- and hypopharynx (ICD-9 146-8) and larynx (ICD-9 161) were included in the study. Stepwise multiple logistic regression was used to calculate the odds ratio (OR) of late versus early stage disease for selected study variables. The sample comprised 188 subjects. Multivariate analysis found that having a pharyngeal cancer (OR 9.26; 95% CI 4.02-21.32; P: 0.0001) a professional delay > 1 month (OR 2.28; 95% CI 1.13-4.64; P: 0.022) and age > or = 65 years (OR: 0.45; 95% CI: 0.22-0.91; P: 0.024) were predictive of late stage disease. A dose-response relationship between professional delay and OR for late stage disease for the whole sample (P for trend 0.03) and among those with oral cancer (P for trend 0.0001) was found. The results of this study suggest that, among patients with an UADT cancer, professional delays > 1 month are contributing to an increased risk for being diagnosed with late stage disease.

Diagnostic performance of Hybrid Capture human papillomavirus deoxyribonucleic acid assay combined with liquid-based cytologic study

OBJECTIVE

Our purpose was to determine the diagnostic performance of human papillomavirus deoxyribonucleic acid testing when performed on liquid-based (Thin-prep) cytologic samples.

STUDY DESIGN

Thin-prep cytologic study, human papillomavirus deoxyribonucleic acid assay with probes for high oncogenic risk human papillomavirus types (16, 18, 31, 33, 35, 45, 51, 52, and 56), and cervical biopsies on women referred to colposcopy for an abnormal Papanicolaou smear were performed.

RESULTS

Of the 364 patients, 186 (51.6%) had a low-grade squamous intraepithelial lesion or worse by histologic diagnosis. Human papillomavirus deoxyribonucleic acid quantitation was correlated with a histologic diagnosis of squamous intraepithelial lesion (p < 0.0001) and the morphologic severity (p < 0.01). The combination of Thin-prep cytologic study and human papillomavirus deoxyribonucleic acid testing correctly identified 87.7% of histologic low-grade lesions and 95.1% of the women with high grade lesions and invasive cancer (p < 0.01).

CONCLUSIONS

A liquid-based cytologic system provides adequate material for concomitant human papillomavirus testing. Addition of human papillomavirus testing to Thin-prep cytologic study provides significant gains in diagnostic accuracy over either cytologic study or human papillomavirus deoxyribonucleic acid testing alone.

Determinants of low-risk and high-risk cervical human papillomavirus infections in Montreal University students

BACKGROUND

Previous studies have been inconsistent about the degree of sexual transmissibility of cervical human papillomavirus (HPV) infection. The authors hypothesize that risk factors for HPV infection vary according to HPV type.

GOAL

To estimate the prevalence of HPV infection in asymptomatic women and to identify risk factors for overall HPV infection and HPV infection by oncogenic and nononcogenic type.

STUDY DESIGN

A cross-sectional survey was conducted at the McGill University clinic in Montreal. Cervical specimens were collected from 489 female students presenting at the clinic for a routine Papanicolaou test. Data on potential risk factors was obtained by questionnaire. Human papillomavirus DNA was detected by the polymerase chain reaction using consensus primers (MY09/11) followed by hybridization with generic and type-specific probes using Southern blot and dot blot techniques.

RESULTS

The overall HPV prevalence was 21.8%. A low-risk HPV infection was found in 6.2% of the women, 11.8% had a high-risk HPV infection (types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58), 7.1% had an unknown HPV type, and 2.7% had a multiple type infection. Two profiles emerged for sexual activity and risk of HPV infection according to oncogenic risk after multivariate analysis. Lifetime frequency of sexual intercourse and lifetime number of oral sex partners was associated with high-oncogenic-risk HPV infections; however, HPV infection with low-oncogenic-risk types was invariant with respect to markers of sexual activity.

CONCLUSION

These results suggest that there are differences in epidemiologic correlates of transmission between low-risk and high-oncogenic-risk HPV types based on oncogenicity. This finding has important implications for primary prevention of HPV infection and cervical cancer precursors.

The effect of cervical loop electrosurgical excision on subsequent pregnancy outcome: North American experience

OBJECTIVE

Our purpose was to determine pregnancy outcome and parturition in women who were treated by loop electrosurgical excision for squamous intraepithelial lesions.

STUDY DESIGN

A series of 574 consecutive women of reproductive age (15 to 44 years old) were treated by loop electroexcision for low- and high-grade squamous intraepithelial lesions. The incidence of pregnancies was determined in these women within a 3-year period after therapy by comparing the "observed" number of pregnancies with the "expected" number of pregnancies in the study population, assuming that fertility rates in these women were the same as in the untreated general female population. Pregnancy outcome was correlated in the 53 women who were delivered of an infant with the posttreatment appearance of the cervix and birth weight with maternal smoking.

RESULTS

The incidence of pregnancy in the study population was 8.5 per 100 woman years compared with 7.4 per 100 woman years in the untreated central population. Fifty-three women had 54 pregnancies, of which 46 (84%) were live births either at term (40) or between 37 and 39 weeks of gestation (6), and three patients are at present at 24, 34, and 36 weeks of gestation. There were two stillbirths and three first-trimester spontaneous abortions. Premature delivery was not observed. External os stenosis (one case), shortening of the cervix (one case), and repeat electroexcision (four cases) had no adverse effect on pregnancy and parturition. Smoking > or = 10 cigarettes per day before and during pregnancy, rather than loop electrosurgical excision per se, was associated with lower-birth-weight babies than those of nonsmokers (p < 0.01).

CONCLUSION

Loop electrosurgical excision to a maximum depth of 1.5 cm and a mean frontal diameter of 1.8 cm does not appear to have adverse effects on subsequent pregnancy outcome and parturition.

Gastrointestinal health effects associated with the consumption of drinking water produced by point-of-use domestic reverse-osmosis filtration units

During a prospective epidemiological study of gastrointestinal health effects associated with the consumption of drinking water produced by reverse-osmosis domestic units, a correlation was demonstrated between the bacterial counts on R2A medium incubated at 35 degrees C and the reported gastrointestinal symptoms in families who used these units. A univariate correlation was found with bacterial counts on R2A medium at 20 degrees C but was confounded by the bacterial counts at 35 degrees C. Other variables, such as family size and amount of water consumed, were not independently explanatory of the rate of illness. These observations raise concerns for the possibility of increased disease associated with certain point-of-use treatment devices for domestic use when high levels of bacterial growth occur.

Characterization of adhesion plates induced by the interaction of Entamoeba histolytica trophozoites with fibronectin

Entamoeba histolytica trophozoites are pleiomorphic and highly motile cells. Although scarce fibrous material can be identified in the cytoplasm as elements of an organized cytoskeleton, clearly defined actin-containing structures are formed at the site of cell-matrix contact upon the interaction of trophozoites with fibronectin (FN) and other cellular matrix substrates. The structures are reminiscent of the adhesion plaques or focal contacts found in higher eukaryotic cells, where actin filament bundles insert into specialized regions of the plasma membrane and function as signal transduction organelles. Thus, the formation of adhesion plates in this parasitic ameba could be related to the specific signaling responses involved in its invasive behavior. Here, we report the isolation of amebic adhesion plates and the results of their structural and molecular analyses. Filaments, with the characteristic diameter of F-actin, radiating from an electron-dense matrix, are the main feature. Actin is one of the main protein components of the plate; other proteins identified are a FN-binding protein--previously reported as a "putative" FN receptor--the actin-binding proteins myosin II, myosin I, alpha-actinin, vinculin, and tropomyosin. The presence of the isolated plates of several proteases and protein kinases, in particular pp125FAK, is also demonstrated. our results suggest that adhesion plates in amebas are dynamic membrane-cytoskeletal complexes participating not only in the attachment to FN substrates but also providing the structural basis for their involvement in parasite locomotion and invasiveness.

Fibronectin-induced intracellular calcium rise in Entamoeba histolytica trophozoites: effect on adhesion and the actin cytoskeleton

The interaction of Entamoeba histolytica trophozoites with fibronectin (FN) promotes adhesion of the protein to the cells and its later degradation by locally released proteases. Binding to FN-covered surfaces induces, in addition, the formation of actin adhesion plates and focal contacts in the amebas. The signaling mechanisms underlying the response to FN are incompletely understood. In this paper we examined the modifications of cytosolic free calcium ([Ca2+]i) induced in the trophozoites by the interaction with FN and their effect on adhesion and the actin cytoskeleton organization. FN produced a sustained rise of [Ca2+]i that could be correlated to the incremented adhesion to FN-covered surfaces. Further increments in [Ca2+]i produced by Ca2+ ionophores A23187 or ionomycin significantly increased the adhesion of trophozoites, whereas depletion of cytoplasmic Ca2+, by treatment with the ionophores in the absence of external Ca2+ or using the chelator BAPTA/AM, blocked it almost completely. To study the role of internal calcium we used the plant lactone thapsigargin, which was found to produce a transient increase of [Ca2+]i but a low stimulatory effect on adhesion and the organization of actin plates. The shifting of soluble actin to the F-actin form and the stabilization of adhesion plates and focal contacts, seen as results, of the FN stimulus, were positively influenced by rises in [Ca2+]i and negatively affected by its decrement. Additional evidence for Ca2+ -mediated signaling in the response to FN was provided by the poor adhesion and defective actin plate organization observed in trophozoites treated with calmodulin antagonists. The results presented here suggest that FN action is mainly dependent on the influx of external Ca2+.

Comparison between two strategies for umbilical cord blood collection

The use of cord blood (CB) for transplantation has increased greatly in recent years. The collection strategy is the first step in collecting good-quality CB units. There are two main techniques for collecting CB from the umbilical vein: in the delivery room while the placenta is still in the uterus by midwives and obstetricians or in an adjacent room after placental delivery by CB bank trained personnel. In this study, the benefits and disadvantages between the two different CB collection strategies were evaluated, in order to improve CB bank methodology. Valencia CB bank maintains the two different collection strategies. CB was obtained from 569 vaginal and 70 caesarean deliveries and obstetrical and clinical charts were reviewed. Before processing CB units, volume was calculated and samples were drawn for cell counts. After processing and before cryopreservation samples were drawn for cell counts, CD34+cell analysis, viability, clonogenic assays and microbiology were drawn directly from the bags. We compared the efficiency of the two collection techniques. Obstetric data and umbilical CB were obtained from 569 vaginal (264 collected in utero and 305 collected ex utero) and 70 caesarean deliveries. The proportion of excluded CB units before processing was 33% for vaginal ex utero, 25% for vaginal in utero and 46% for caesarean deliveries. Differences were statistically significant. For vaginal deliveries a larger volume and a higher number of nucleated cells, percentage of CD34+ cells and colony-forming units (CFUs) were harvested in the in utero collection group. There was no statistical difference between CB collected after placental expulsion from vaginal and caesarean deliveries. Comparison between all vaginal and caesarean deliveries did not show any difference. We conclude that the mode of collection influences the haematopoietic content of CB donations. Collection before placental delivery is the best approach to CB collection and allows optimisation of CB bank methodology. Caesarean deliveries seem to contain similar progenitor content to vaginal deliveries.

Human papillomavirus infection in postmenopausal women with and without hormone therapy

OBJECTIVE

To determine whether postmenopausal hormone therapy is associated with high-risk human papillomavirus (HPV) infection.

METHODS

The detection rate of HPV DNA was studied in cellular residue from liquid-based collection tubes taken from 180 postmenopausal hormone users attending a menopausal clinic and 126 postmenopausal nonusers. The samples were analyzed with a hybrid capture technique using a mix of high- to intermediate-risk viral RNA probes. In all patients, information on potential confounding factors for HPV infection, including sociodemographic, reproductive, and gynecologic characteristics, was obtained.

RESULTS

The prevalence of HPV DNA in this cohort of postmenopausal women was 1% (three of 306); only two of the 180 current users and one of the 124 nonusers tested positive. Only one of the three women with HPV-positive tests had lesional tissue (i.e., vulvar condylomata acuminata). The remaining two HPV-positive women had negative cytology, colposcopy, and biopsy. In all three cases, viral burden was low, about 10 pg per cellular sample. The very low HPV prevalence precluded the analysis of correlation with age, ethnicity, education, sexual history, smoking, history of abnormal Papanicolaou smear, therapy for HPV-related lesions, and contraceptive use.

CONCLUSION

Identification of high-risk HPV types in post-menopausal women is rare, as detected by hybrid capture in cellular residue from the liquid-based cytology-collection system. Postmenopausal hormone therapy does not appear to promote viral replication or the risk of carrying high-risk HPV DNA or related lesional tissue in the lower genital tract.

Nonisotopic detection and typing of human papillomavirus DNA in genital samples by the line blot assay. The Canadian Women's HIV study group

The line blot assay, a gene amplification method that combines PCR with nonisotopic detection of amplified DNA, was evaluated for its ability to detect human papillomavirus (HPV) DNA in genital specimens. Processed samples were amplified with biotin-labeled primers for HPV detection (primers MY09, MY11, and HMB01) and for beta-globin detection (primers PC03 and PC04). Amplified DNA products were hybridized by a reverse blot method with oligonucleotide probe mixtures fixed on a strip that allowed the identification of 27 HPV genotypes. The line blot assay was compared to a standard consensus PCR test in which HPV amplicons were detected with radiolabeled probes in a dot blot assay. Two hundred fifty-five cervicovaginal lavage specimens and cervical scrapings were tested in parallel by both PCR tests. The line blot assay consistently detected 25 copies of HPV type 18 per run. The overall positivity for the DNA of HPV types detectable by both methods was 37.7% (96 of 255 samples) by the line blot assay, whereas it was 43. 5% (111 of 255 samples) by the standard consensus PCR assay. The sensitivity and specificity of the line blot assay reached 84.7% (94 of 111 samples) and 98.6% (142 of 144 samples), respectively. The agreement for HPV typing between the two PCR assays reached 83.9% (214 of 255 samples). Of the 37 samples with discrepant results, 33 (89%) were resolved by avoiding coamplification of beta-globin and modifying the amplification parameters. With these modifications, the line blot assay compared favorably to an assay that used radiolabeled probes. Its convenience allows the faster analysis of samples for large-scale epidemiological studies. Also, the increased probe spectrum in this single hybridization assay permits more complete type discrimination.

Baseline sero-epidemiology of hepatitis B virus infection in children and teenagers in Italy. A survey before mass hepatitis B vaccination

During the period May 1987 to November 1989, the prevalence of hepatitis B virus (HBV) markers was determined by ELISA in serum samples of 7405 (55% male, 45% female) apparently healthy persons 3-19 years of age in Italy. Earlier studies of adults there had shown an intermediate degree of HBV endemicity (hepatitis B surface antigen carrier rate greater than 2%). Persons were selected by systematic cluster sampling in five different geographical areas of Italy. The overall prevalence of hepatitis B surface antigen (HBsAg) was 0.6%. The overall prevalence of at least one marker of HBV was 2.8%; it increased from 1.7% among children 3-5 years of age to 4.5% in teenagers 17-19 years of age (P less than 0.001). The prevalence of any HBV marker was higher in southern then in northern areas (3.5% vs. 1.8%, P less than 0.001). A significant association was found with sociodemographic features. Persons whose fathers had less than 6 years of schooling had a 2.3-fold risk (C.I. 95% = 1.5-3.4) while those belonging to a household of six or more under one roof had a 1.7-fold risk (C.I. 95% = 1.2-2.4) of previous exposure to HBV infection. These findings indicate that, today in Italy, exposure to HBV infection at a young age is very low and suggest a shift towards a low degree of endemicity following improvements in socio-economic conditions, decreased family size and increasing use of disposable syringes during recent years.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the potential carcinogenicity of 60 Hz linear sinusoidal continuous-wave magnetic fields in Fischer F344 rats

Electric and magnetic fields (EMFs) associated with the production, transmission, and use of electricity are ubiquitous in industrialized societies. These fields are predominantly of low frequency (50/60 Hz) and are generally of low intensity. Review of the epidemiological evidence shows that the association between exposure to EMFs and cancer is weak and inconsistent, and generally fails to show a dose-response relationship. Moreover, in view of the methodological problems of these epidemiological studies, animal and laboratory studies are urgently needed to determine whether EMFs could be initiators and/or promoters of cancers. The objective of the present study was to determine whether chronic exposure to 60 Hz linear (single axis) sinusoidal, continuous-wave magnetic fields (MFs) of different intensities might increase the risk of leukemia and solid tumor development in rodents born and raised under these fields. Five groups of 50 female F344 rats were exposed for 20 h/day to 60 Hz MFs at intensities of <0.02 (sham controls), 2, 20, 200, and 2000 microT. Full body exposure to the different fields was administered for 104 wk starting from the prenatal period (2 days before birth) and continuing during lactation and weaning until late adult life. Body weight, survival, and clinical observations were evaluated in all groups of animals during in-life exposure. Necropsy was performed on all exposed and control animals that died, were found moribund, or were killed at termination of the study. To preserve and demonstrate the absence of any experimental bias, all clinical observations and pathological evaluations were conducted under "blinded" conditions. Fifty organs and tissues were evaluated in each animal, with special attention to the incidence of mononuclear cell leukemia, brain tumors, and mammary tumors. The findings from this chronic carcinogenicity study demonstrate that, under our defined experimental conditions, exposure to 60 Hz linear (single axis) sinusoidal, continuous wave MFs did not affect animal survival, solid tumor, or mononuclear cell leukemia development in female F344 rats. No statistically significant, consistent, positive dose-related trends with the number of tumor-bearing animals per study group could be attributed to MF exposure.

Conventional cervical cytologic smears vs. ThinPrep smears. A paired comparison study on cervical cytology

OBJECTIVE

To compare the time required for evaluation, the diagnostic accuracy and quality of conventional glass slide smears vs. ThinPrep smears in 365 women.

STUDY DESIGN

Both smears were obtained at the same time using the Accellon Combi cervical biosampler. Histology served as the diagnostic "gold standard."

RESULTS

The average screening time was 1 minute, 23 seconds, shorter per smear with the ThinPrep method as compared to the conventional glass slide (P < .001). Direct diagnostic agreement between the two smear methods was obtained in 311 of 364 evaluable smears (85.4%, kappa = .63). Despite the relatively high rate of "adequate but limited by absence of transformation zone components" observed with the ThinPrep method, the sensitivity and specificity of the ThinPrep method was slightly greater but not statistically significantly different than the conventional technique, irrespective of the disease categories (low and high grade squamous intraepithelial lesion and invasive cancer).

CONCLUSION

The shorter time required to screen ThinPrep smears compared to conventional smears in this study was not sufficiently important to offset the current unit price for preparing ThinPrep smears.

Clinical simulation in teaching preclinical dentistry

Current and projected approaches to dental education have created a wide interest in clinical simulation, and recently there has been a considerable expansion in the availability of experiential learning tools which imitate "real life" clinical conditions in dentistry. These include patient simulation devices such as heads, jaws, teeth and clinical environments, standardized patients, interactive video-discs and computer-based instruction. This paper reviews some of the equipment currently available for simulation of clinical procedures, and assesses the initial experiences and responses of 2nd, 3rd and 4th year undergraduate dental students at The University of Melbourne to case-based simulations in a patient simulator in comparison with preclinical exercises in a traditional bench and manikin laboratory. Student response to teaching and learning in the simulator over a 3-year evaluation period, collected via a student questionnaire was uniformly positive. Students were very enthusiastic about the learning environment and educational approach, preferring it to traditional preclinical laboratory instruction.

Fibronectin-derived fragments as inducers of adhesion and chemotaxis of Entamoeba histolytica trophozoites

Active migration of Entamoeba histolytica trophozoites through extracellular matrixes might play a role in host tissue destruction. Trophozoites degrade soluble fibronectin (FN) bound to their surface and adhere to substrate-bound FN, producing local degradation. FN proteolytic fragments were used to determine the nature of adhesion and motility-promoting domains within the protein. The 70-kDa fragment (amino-terminal end) promoted the highest adhesion, followed by the 120-kDa fragment, which contains the cell-binding domain. The 25-kDa fragment (carboxy-terminal end of the A chain) promoted half the adhesion, while two Hep II-binding fragments had no effect. The 70- and 120-kDa fragments also stimulated directed migration and chemokinesis. Intact FN and the 25-kDa fragment showed lower stimulation. The Hep II-binding fragments had no activity. Results support previous evidence for distinct cell-surface components as mediators of adhesion to FN and trophozoite motility and the potential importance of cell matrix recognition and degradation in their invasive behavior.

Predictors of professional diagnostic delays for upper aerodigestive tract carcinoma

In spite of the belief that cancer mortality can be reduced if lesions are detected, diagnosed and treated at an early stage, the predictors of diagnostic delays for upper aerodigestive tract (UADT) cancers have been the subject of little research. The aim of this study was to investigate the role of selected variables as predictors of professional diagnostic delays in a sample of UADT cancer patients. Patients diagnosed with squamous cell carcinoma of oral cavity sites (ICD-9 141, 143-5) oro-, naso- and hypopharynx (ICD-9 146-8) and larynx (ICD-9 161) were included in the study. Multiple logistic regression was used to calculate the odds ratio (OR) for professional delay > 1 month versus professional delay < 1 month for selected study variables. The sample comprised 188 subjects. Multivariate analysis found that the presence of comorbidity at the time of presentation of UADT symptoms (OR 2.84; 95% CI 1.35-5.98), age > or = 65 years (OR 0.31; 95% CI 0.15-0.64), higher education (OR 0.45; 95% CI 0.22-0.93) and cancer at an oral cavity site (OR 0.31; 95% CI 0.15-0.64) were the explanatory variables for professional delay. This study suggests that, among UADT cancer patients, the presence of comorbidity at the time of presentation increases the odds for a professional delay > 1 month, while older age, higher education and oral cancer reduce the odds.