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Biomedical subjects

E Franco

Publications and source records attributed to E Franco.

At least 55 records · Page 3Linked to original sources
PubMed1999

Calcium- and magnesium-dependent aggregation of legume seed storage proteins.

The solubility characteristics and sedimentation behavior of total or individual globulins from legume seeds [Lupinus albus L., Pisum sativum L., and Glycine max (L.) Merr.] were investigated. The typical insolubility of globulins detected during their extraction seems to be due to the presence of a low molecular weight factor(s) in the seed extract. The solubility of the purified globulins decreases with increasing concentrations of calcium and/or magnesium, but not of other cations, showing minimum values at concentrations that vary with the particular globulin considered. Ultracentrifugation analyses revealed that the Ca(2+)- and/or Mg(2+)-induced insolubilization of the globulins involves the formation of high-order aggregates of molecules of the same or of different globulins. These macromolecular structures are dissociated under conditions of high ionic strength, suggesting the involvement of electrostatic interactions in the aggregation process. The degree of association relies heavily on the amount of Ca(2+) and/or Mg(2+) available, on the presence of chelating agents for these divalent cations, and on the ionic strength of the surrounding medium. The possible physiological significance of the findings is discussed.

Calcium Chloride↗
PubMed1999

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.

Cervix Uteri↗
PubMed1999

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.

Adult↗
PubMed1999

[Cerebral abscess as first manifestation of a familial pulmonary arteriovenous fistula].

Pulmonary arteriovenous fistula in a 63-year-old woman with no relevant medical history presented with neurological symptoms secondary to multiple polymicrobial abscesses. As a result of this finding, relatives were examined under suspicion of the presence of systemic angiomatosis (hemorrhagic hereditary telangiectasia or Rendu-Osler-Weber disease), which is asymptomatic in many victims. Follow-up and early diagnosis is crucial to preventing severe neurological complications by treatment of arteriovenous malformations and antibiotic prophylaxis during dental or other invasive procedures.

Arteriovenous Fistula↗
PubMed1999

[Mitochondrial encephalomyopathy of late presentation with progressive ophthalmoplegia, tremor and diffuse leukoencephalopathy].

A 60-year-old woman had developed ptosis, progressive external ophthalmoplegia and action tremor over the last ten years. Physical examination also revealed short stature and retinal pigmentation. Anaerobic forearm exercise test showed increase of basal lactate and rise of lactate/piruvate index. Biceps biopsy displayed numerous ragged red fibers. Respiratory chain studies were consistent with complex I deficiency. Point mutations or deletions in mitochondrial DNA were not found. MR identified a diffuse leukoencephalopathy over both cerebral hemispheres, mesencephalon, pons and cerebellum. The late and sporadic onset of a progressive external ophthalmoplegia outlining a Kearns-Sayre syndrome is striking. A leukoencephalopathy associated with mitochondrial encephalomyopathy is an infrequent finding. The action tremor of this patient could be symptomatic of her mitochondrial disfunction.

Biopsy↗
PubMed1998

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.

Adult↗
PubMed1998

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.

Adult↗
PubMed1998

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.

Adolescent↗
PubMed1998

The importance of the case management approach: perceptions of multidisciplinary team members.

This article attempts to determine the importance of the case management approach as perceived by health professionals working in multidisciplinary teams. The case management approach is reported to streamline care and contain cost. The literature calls for continuing education in a multidisciplinary forum for all health professions; however, data on perceived or actual educational needs is scant. One hundred forty-one health practitioners working in clinical teams rated four case management components on 100 mm scales: assessing patient needs; educating caregivers; community agency liaison; and, cost monitoring. Statistical significance of differences was determined by Mann Whitney U and Wilcoxon rank sum testing. All scores were high, and of all variables tested, varied only by profession (p < .01). Administrators and nurses had relatively higher scores than physicians and physiotherapists. Patient needs were valued above education, education above liaison, and liaison above cost monitoring (p < .01, < .01, < .01, respectively). Continuing education providers should note that health professionals value case management and may be receptive to education. Further study is required to design educational modules for multidisciplinary use, test impact on knowledge and skills, and determine if transdisciplinary case management education can improve quality of care while containing costs.

Attitude of Health Personnel↗
PubMed1998

[Familial internal carotid dissection].

Cervicocerebral arterial dissections is responsible for 20% of first strokes in young adults. Several diseases of the connective tissue and wall vessels anomalies are considered predisposing of arterial dissection. Familiar cases have been reported in 5%, according to hereditary primary arteriopathy, such as fibromuscular dysplasia. However, the nature of this arteriopathy has been rarely proved. We present two sisters with spontaneous dissection of the internal carotid artery with details suggestive of an atypical way of fibromuscular dysplasia in one of them.

Angiography↗
PubMed1997

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.

Adult↗
PubMed1997

Accumulation of a lectin-like breakdown product of beta-conglutin catabolism in cotyledons of germinating Lupinus albus L. seeds.

During germination of Lupinus albus seeds, a 20-kDa polypeptide accumulates in the cotyledons of 4-d-old plants (Ferreira et al., 1995b, J Exp Bot 46: 211-219). Immunological, polypeptide cleavage with cyanogen bromide and amino acid sequencing experiments indicate that the 20-k-Da polypeptide and ubiquitin are structurally unrelated. However, there is a strong sequence homology between the 20-kDa polypeptide and the vicilin-like storage proteins from pea and soybean. Our results indicate that the 20-kDa polypeptide is an intermediate breakdown products of beta-conglutin catabolism, the vicilin-like storage protein from L. albus, and that its interaction with anti-ubiquitin antibodies results from the recognition of the antibodies by the 20-kDa polypeptide rather than by the opposite. Besides rabbit anti-ubiquitin antibodies, the 20-kDa polypeptide interacts with a variety of glycoproteins, including immunoglobulin G from several animal species, peroxidase and alkaline phosphatase, suggesting that it possess a lectin-type activity. Its activity is resistant to sodium dodecyl sulfate or methanol treatments, boiling and autoclaving. Purification of the 20-kDa polypeptide and immunological studies with anti-20-kDa-polypeptide antibodies showed that the non-glycosylated polypeptide is part of a glycoprotein with an estimated molecular mass of 210 kDa, composed of several types of structurally related subunit with molecular masses ranging from 14 to 50 kDa. Purified native protein containing the 20-kDa polypeptide self-aggregates in a calcium-dependent manner as reported for some glycosylated lectins. The possible physiological function of the 20-kDa polypeptide is discussed.

Amino Acid Sequence↗
PubMed1997

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.

Aged↗
PubMed1997

The future of HPV testing in clinical laboratories and applied virology research.

BACKGROUND: Human papillomaviruses (HPV) are now considered etiologic agents of cancer of the uterine cervix. Adjunctive diagnostic procedures for the detection of HPV infection could increase the sensitivity of primary and secondary screening of cervical cancer. HPV testing could also improve the specificity of screening programs resulting in avoidance of overtreatment and saving of costs for confirmatory procedures. OBJECTIVES: To review the rationale of HPV testing in genital diseases and the potential applications of HPV DNA detection methods for clinical and epidemiological purposes. RESULTS: Progression of HPV infection is associated with the persistence of HPV infection, involvement of high-risk HPV types, high HPV viral load in specimens, integration of viral DNA and possibly the presence of cofactors. The design of HPV diagnostic tests will need to take into account these parameters of disease progression. HPV DNA detection techniques based on signal-amplification are standardized, commercially available and detect several high-risk HPV types. They increase the sensitivity of screening for high-grade and low-grade lesions. Although they may yield false-negative results in the presence of significant HPV-related disease, new test formats could resolve this weakness. Amplification techniques are ideal instruments for epidemiologic purposes since they minimize misclassification of HPV infection status and allow for the detection of low viral burden infections. They are currently not readily applicable to diagnostic laboratories. CONCLUSIONS: Before recommending HPV testing, prospective trials of untreated LSIL with HPV testing as well as the determination of the efficacy and cost-effectiveness of novel HPV tests, need to be completed.

DNA, Viral↗
PubMed1997

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.

Animals↗
PubMed1997

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.

Age Factors↗