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Biomedical subjects

E Franco

Publications and source records attributed to E Franco.

At least 19 recordsLinked to original sources
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

[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↗
PubMed1997

Evaluation of renographic and metabolic parameters in human kidney transplantation.

BACKGROUND: The aim of this work is to demonstrate that the value of the mean transit time (MTT) obtained from the 99mTc-MAG3 renogram deconvolution is related to the levels of adenine nucleotides determined in cortical biopsies from transplanted kidneys. METHODS: The functional state was estimated by means of the MTT and the initial height (H0) of the renal retention function obtained from the 99mTc-MAG3 renogram deconvolution and by the measure of adenine nucleotides obtained from biopsies. We studied 30 kidney graft recipients, 25 normal functioning grafts (NFG) and 5 with acute tubular necrosis (ATN). RESULTS: The MTT is significantly longer for ATN (p < 0.001). The initial uptake values (H0) are significantly lower for ATN (p < 0.001). The sum of adenine nucleotides (SAN) is significantly greater for NFG than for ATN (p < 0.001). The values of the MTT seem to reflect the energy state of the cells in transplanted kidney. CONCLUSION: The analysis of MTT may be indicative of the functional metabolic recovery and thus it may be predictive of the renal graft function at least in the same extent than the biochemical analysis of a cortical renal biopsy immediately after blood reperfusion of the tissue.

Adenine Nucleotides↗
PubMed1997

[A clone of Neisseria meningitidis serogroup C was responsible in 1994 of an unusual high rate of strains with a moderate resistance to penicillin in Caracas (Venezuela)].

BACKGROUND: The aim of the study was to analyse meningococcal strains isolated from patients in Caracas (Venezuela) with epidemiological markers and to determine their susceptibility to antimicrobial agents. METHODS: We analyzed 29 meningococcal clinical strains isolated during 1994 in Caracas by serogrouping, serotyping and subserotyping, multilocus enzyme analysis (MEE), ribotyping and pulse field electrophoresis (PFGE) profile. We also determined the Minimal Inhibitory Concentration (MIC) to 5 antimicrobial agents. RESULTS: Twenty four (82.7%) were group C meningococcal strains. All group C meningococci were characterized as C: 2b: P1.5, belonging to the same electrophoretic type (ET) by MEE and showing the same profile by PFGE by using Bg/II endonuclease restriction enzyme. These group C meningococci showed two different patterns by ribotyping, with only one band difference. All Group C and one group B N. meningitidis isolates were moderately resistant to penicillin (MIC > or = 0.12 mg/l). CONCLUSIONS: During 1994 an unusual high incidence of meningococcal strains moderately resistant to penicillin (PenMR) was detected in Caracas (Venezuela). A clone of C: 2b: P1.5 meningococci seem to be responsable for this high incidence of PenMR isolates.

Cross Infection↗
PubMed1996

Covalent dimerization of ribulose bisphosphate carboxylase subunits by UV radiation.

The effect of UV radiation (UV-A, UV-B and UV-C) on ribulose bisphosphate carboxylase from a variety of plant species was examined. The exposition of plant leaves or the pure enzyme to UV radiation produced a UV-dependent accumulation of a +5 kDa polypeptide (P65). Different approaches were utilized to elucidate the origin and structure of P65: electrophoretic and fluorographic analyses of 35S-labelled ribulose bisphosphate carboxylase exposed to UV radiation and immunological experiments using antibodies specific for P65, for the large and small subunits of ribulose bisphosphate carboxylase and for high-molecular-mass aggregates of the enzyme. These studies revealed that P65 is a dimer, formed by the covalent, non-disulphide linkage of one small subunit with one large subunit of ribulose bisphosphate carboxylase. For short periods of time (< 1 h), the amount of P65 formed increased with the duration of the exposure to the UV radiation and with the energy of the radiation applied. Prolonged exposure to UV radiation (1-6 h) resulted in the formation of high-molecular-mass aggregates of ribulose bisphosphate carboxylase. Formation of P65 was shown to depend on the native state of the protein, was stimulated by inhibitors of enzyme activity, and was inhibited by activators of enzyme activity. A UV-independent accumulation of P65 was also achieved by the in vitro incubation of plant crude extracts. However, the UV-dependent and the UV-independent formation of P65 seemed to occur by distinct molecular mechanisms. The UV-dependent accumulation of P65 was immunologically detected in all species examined, including Lemna minor, Arum italicum, Brassica oleracea, Triticum aestivum, Zea mays, Pisum sativum and Phaseolus vulgaris, suggesting that it may constitute a universal response to UV radiation, common to all photo-synthetic tissues.

Chromatography↗
PubMed1996

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+.

Actins↗
PubMed1996

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.

Adolescent↗