Bayesian network analysis of resistance pathways against HIV-1 protease inhibitors

Interpretation of Human Immunodeficiency Virus 1 (HIV-1) genotypic drug resistance is still a major challenge in the follow-up of antiviral therapy in infected patients. Because of the high degree of HIV-1 natural variation, complex interactions and stochastic behaviour of evolution, the role of resistance mutations is in many cases not well understood. Using Bayesian network learning of HIV-1 sequence data from diverse subtypes (A, B, C, F and G), we could determine the specific role of many resistance mutations against the protease inhibitors (PIs) nelfinavir (NFV), indinavir (IDV), and saquinavir (SQV). Such networks visualize relationships between treatment, selection of resistance mutations and presence of polymorphisms in a graphical way. The analysis identified 30N, 88S, and 90M for nelfinavir, 90M for saquinavir, and 82A/T and 46I/L for indinavir as most probable major resistance mutations. Moreover we found striking similarities for the role of many mutations against all of these drugs. For example, for all three inhibitors, we found that the novel mutation 89I was minor and associated with mutations at positions 90 and 71. Bayesian network learning provides an autonomous method to gain insight in the role of resistance mutations and the influence of HIV-1 natural variation. We successfully applied the method to three protease inhibitors. The analysis shows differences with current knowledge especially concerning resistance development in several non-B subtypes.

Impact of medical waste incineration in the atmospheric PCDD/F levels of Porto, Portugal

As a consequence of a monitoring program of a new municipal waste incinerator initiated in 1998, a large data-base of dioxin and furan concentrations in the atmosphere of the metropolitan area of Porto, in northern Portugal, has been collected. The existence of this data coincides with the shutdown in January 2001 of two medical waste incinerators that were under operation in the inner city of Porto. Dioxin emissions from these facilities were measured indicating emissions 100 to 1000 times larger than recent European Union directive limits. Data show that the shutdown of these two units had a clear effect on the improvement of air quality in the region that was observed either on the overall level of dioxins and furans or as in subtle alterations of the homolog pattern of these compounds in the atmosphere.

[Uterine inversion]

The uterine inversion is a rare but serious pathology of the delivery. We describe two cases of uterine inversion of secondary and quaternary degree; the first had a delay diagnosis and the second having a return after the manual replacement, finishing both on surgical resolution. The authors describe the causal factors, the diagnosis and the therapeutic of uterine inversion.

Frequent 7q gains in flow cytometric multiploid/hypertetraploid breast carcinomas: a study of chromosome imbalances by comparative genomic hybridisation

OBJECTIVE

To investigate underlying genetic events associated with complex DNA ploidy breast carcinomas.

METHODS

Screening for chromosome imbalances was carried out using comparative genomic hybridisation (CGH) in 14 frozen samples of tumour from a series of 13 breast cancer patients with multiploid (n = 11) and hypertetraploid (n = 2) tumours. They had previously been analysed by DNA flow cytometry and also assessed immunohistochemically for p53 tissue expression. Ploidy status was determined on frozen samples using the Multicycle software program.

RESULTS

The total number of copy gains (n = 242) was significantly greater than the number of copy losses (n = 51). The mean (SD) number of gains per sample was 17.3 (5.7), and of losses, 3.6 (4.2) (p = 0.0001). Gains of chromosomal regions at 1q (14/14; 100%), 7q (12/14; 85.7%), and 3q (11/14; 78.6%), as well as 1p, 2q, 5p, 8q, and 13q (10/14; 71.4%) were the most frequent aberrations in this series. Losses were most commonly found on 17p (5/14; 35.7%). Three patients dying of the disease had tumours with high level amplifications at 1q12-qter, 3q22-q25, and 8q22-q23 regions. Six cases had p53 overexpression, of whom four showed 12q gains and two showed 17p losses.

CONCLUSIONS

There is a very high incidence of genetic aberrations, mainly related to chromosomal gains, in this subgroup of aneuploid breast cancer patients, associated with a poor clinical outcome. The 7q locus, not previously reported as showing frequent changes in breast cancer, was found to be a potential site for some candidate oncogenes.

[Sudden transformation of pulmonary stenosis to trilogy of Fallot in a 65 year old patient]

The authors report the case of a 64 year old woman with typical valvular pulmonary stenosis in whom spontaneous and sudden reopening of the foramen ovale resulted in cyanosis. Transthoracic echocardiography with injection of contrast provides a complete diagnosis: valvular pulmonary stenosis with a mean pressure gradient of 83 mmHg and massive right-to-left interatrial shunt. The malformation was treated by interventional catheterisation in a two-stage procedure: pulmonary valvuloplasty followed by closure of the foramen ovale because of the persistence of a right-to-left interatrial shunt. The functional improvement was followed by the appearance of effort angina. Coronary angiography showed single vessel disease of the left anterior descending artery treated by stenting. The long-term outcome was satisfactory.

Rate and incidence estimates of recent human immunodeficiency virus type 1 infections among pregnant women in Sao Paulo, Brazil, from 1991 to 2002

The serological testing algorithm for recent human immunodeficiency virus (HIV) seroconversion (STARHS) was employed to estimate HIV incidence among pregnant women from Sao Paulo, Brazil. A cross-sectional study (1999 to 2002) showed an incidence of infection of 0.2 per 100 pregnant women per year (95% confidence interval, 0.041 to 0.608). Western blot profiles suggested an association between results of the STARHS analysis and gp41/gp31 bands.

Liver transplantation in pigs with small-for-size grafts: effect of portocaval shunt

Small-for-size livers are associated with graft dysfunction, probably due to portal hyperperfusion. Modulation of the recipient portal inflow is a new option in these cases. This article sought to analyze the effect of portocaval shunt in small-for-size liver grafts in pigs. Twelve liver transplants were performed in white pigs. The donors' mean weight was 10 kg and the recipient's mean weight was 34 kg. In all cases a standard technique was utilized. A portocaval shunt was added on the back-table in six cases. One hour after the procedure, the livers were sent for histologic examination. In all six cases without a portocaval shunt, the livers showed hemorrhagic necrosis, which was not observed in any of the six livers with a portocaval shunt. In small-for-size liver grafts in pigs, a portocaval shunt prevents hemorrhagic necrosis.

CD4+ T-cell recovery and clinical outcome in HIV-1-infected patients exposed to multiple antiretroviral regimens: partial control of viremia is associated with favorable outcome

The goal of antiretroviral therapy is clinical benefit through the suppression of viral replication and the immunologic reconstitution of HIV-1-infected patients. In spite of the availability of different highly active antiretroviral therapy only some patients sustain undetectable plasma viremia. We performed an observational study from October 1987 to February 2001 on immunologic and clinical outcome of 148 HIV-1-infected patients from an open clinical cohort at São Paulo University, Brazil. The median T CD4+ at starting first monitored regimen was 227 cells per microliter, with 65% of patients previously exposed to antiretroviral regimens, mostly dual therapy. Virologic response to antiretroviral therapy, after a median period of 179 weeks of monitored treatment, allowed classifying patients as aviremic (RNA plasma viremia below 500 copies per milliliter); viremic (current viral load at historic levels), and viremic-attenuated groups (detectable viremia, but > 1 log viral suppression). HIV RNA viral load, T CD4+ cells count, HIV-1 pol sequencing, inflammatory parameters, and clinical events were documented during a median follow-up of 251 weeks. This study observed better clinical and immunologic responses in the aviremic group, but the viremic-attenuated group showed a significant gain in CD4+ cells (p < 0.013) and a decreased number of cases progressing to an AIDS-defining clinical condition (p < 0.001) compared to the viremic group.

Coating of solid-phase microextraction fibers with chemically bonded silica particles: selective extraction of polycyclic aromatic hydrocarbons from drinking water samples

In this study, solid-phase microextraction fibers coated with modified silica particles (5 pm dp) bonded to methyl (C1), hexyl (C6), octyl (C8), and polymeric octadecyl (C18) groups are prepared and evaluated. Selective extraction of polycyclic aromatic hydrocarbons (PAHs) from river water is used to demonstrate the selective behavior of the fibers as a function of the alkyl chains bonded to the silica phase. Scanning electron micrography suggests that the coating structure consists in a monolayer of particles bonded to the surface of the fiber. The behavior of the fibers upon the extraction of PAHs from water samples is compared with the use of standard polydimethylsiloxane fibers that are commercially available.

Osmolality of solutions, emulsions and drugs that may have a high osmolality: aspects of their use in neonatal care

OBJECTIVE

Administration of some hypertonic substances to neonates has been associated with a variety of adverse effects. This study was conducted to determine the osmolality of intravenous drugs and solutions used in neonates receiving intensive care.

METHODS

Osmolality was measured by freezing point depression. Vasoactive drugs, diuretics, anticonvulsants, antimicrobials, and glucose and electrolyte solutions were some of the substances analyzed.

RESULTS

The osmolalities of 90 substances were measured; the respective intra-assay and interassay coefficients of variation were always less than 5%. A few drugs were found to be extremely hypertonic (> 8000 mOsm/kg), and most of them contain propylene glycol as vehicle (e.g. digoxin, phenytoin, diazepam and phenobarbital). Other drugs, at the same concentration, evidenced a significant discrepancy of osmolality depending on the trademark.

CONCLUSIONS

The finding of some extremely hypertonic drugs highlights the need for further investigation in order to study their potential adverse effects in neonates, as well as to evaluate any advantage in diluting, infusing slowly or even avoiding such substances. Given the fact that there exists a discrepancy in osmolalities in some drugs at the same concentration depending on the trademark, the more isotonic solutions should be the preferred choice for intravenous administration.

[Cardiovascular disease and pregnancy]

Cardiovascular disease is the most important non-obstetric cause of disability and death in pregnant women, occurring in 1% of pregnancies. The added hemodynamic burden of pregnancy, labor and delivery can aggravate symptoms and precipitate complications in women with pre-existent cardiac disease. Additionally, it can reveal an underlying unknown pathology. The authors present three cases of pregnant women with mechanical prosthetic valve, cyanotic congenital heart disease and intracardiac shunt. Antenatal, labor and postpartum obstetric management is subject of debate.

Neurological teleconsultation for general practitioners

A neurology teleconsulting network was implemented between a university hospital in Lisbon and five nearby health centres. PCs equipped for videoconferencing were installed, connected by ISDN lines at 128 kbit/s. Fifty-three general practitioners (GPs) were surveyed. The survey showed that the GPs had difficulties in using computers, but they had definite intentions to use teleconsultation for neurology cases and 83% of the respondents stated that they would probably use the technique. During the study, 90 neurology teleconsultations took place over 55 weeks. The average consultation rate was 1.6 teleconsultations per week (SD 1.3, range 0-6). The conferences lasted 10-45 min. Longer teleconsultations were mainly due to technical difficulties in using computers on the part of users with a low level of computer literacy. The patients were 42 males and 46 females, with a mean age of 38 years (SD 20, range 1-84); two patients were discussed twice. The benefits consisted mainly of advice on patient medication, diagnosis and the prevention of unnecessary specialist consultations or laboratory examinations. Doctor-doctor teleconsultation allows the rapid resolution of queries which otherwise cause stress to patients and increase the cost and complexity of care.

Impact of adherence to antiretroviral therapy in HIV-1-infected patients at a university public service in Brazil

The objective of this study was to assess if a simple evaluation, adherence to antiretroviral therapy, would correlate to clinical and laboratory outcomes. We followed an open cohort of patients from a public teaching hospital AIDS outpatient clinic. Patients were categorized according to adherence as: regular (Reg), optimal, all doses all days, tolerating only irregular timing (+/- 2 hours) of intake; quasi-regular (qReg), those missing up to four doses or 1 full day during a month; irregular (Irreg), all other irregular regimens, and ignored (Ign), those without information. The results from a simple questionnaire were compared to CD4+ cell counts and human immunodeficiency virus type 1 (HIV-1) RNA plasma viremia. One hundred eighty-two HIV-1-infected patients (126 males, 69%; 56 females, 31%) were analyzed. Information on adherence was available for 168 (90%). Reg adherence was reported by 75 (41%) patients, qReg adherence by 35 (19%), and Irreg by 53 (29%) of patients. The main reasons for nonadherence were forgetfulness, intolerance, use of alcohol, and misunderstanding of prescription. A significant increase of CD4+ T-cell counts and absolute gain were only observed among Reg and qReg users (p < 0.001). The median viral RNA load log10 decreases were -1.68, -1.45, -0.9 log, respectively, for Reg, qReg, and Irreg patients (p = 0.043, Kruskal-Wallis). Development of and death from AIDS occurred almost exclusively among those with Ign or Irreg adherence. Previous use of antiretroviral therapy may have had an impact in treatment response. Individuals who were treatment-naive were more likely to be Reg users (41%). Although more refined methods to assess adherence should be implemented when available, the inability to do so should not prevent simple, albeit subjective measurements that also correlate with favorable outcome. Mechanisms to improve adherence should be considered an integral part of antiretroviral therapy.

[Type B natriuretic peptide in the diagnosis of heart failure with preserved systolic function]

BACKGROUND

Heart failure (HF) with preserved left ventricular systolic function (LVSF) is observed in up to 50% patients with HF. There is no consensus on non-invasive diagnosis of this entity.

OBJECTIVE

Evaluation of B-type natriuretic peptide (BNP) in the diagnosis of HF with preserved left ventricular systolic function.

DESIGN

Prospective study.

PATIENTS

One hundred and seventy-six consecutive patients with suspected HF were evaluated. Patients were classified as having HF with preserved LVSF, if they had symptoms and signs of HF, an ejection fraction greater than 40% and an abnormal Doppler pattern of the mitral inflow or atrial fibrilation and no other causes for the symptoms. All patients had a 12-lead EKG, chest roentgenogram, simple spirometry, M-mode and 2D echocardiogram with pulsed Doppler study of transmitral inflow and determination of plasma BNP levels.

RESULTS

Of the 176 patients, 65 had ejection fraction greater than 40%. Of these patients 46 were classified as having HF with preserved LVSF and 19 as not having HF. Patients with HF and preserved LVSF were older, had a higher systolic blood pressure (SBP), less pathologic Q waves on ECG and higher left ventricular ejection fraction and plasma BNP than patients without HF. Multivariate analysis revealed that BNP and SBP were independently associated with the diagnosis of HF. The accuracy of BNP in the diagnosis of HF with preserved LVSF evaluated by the area under the receiver operating characteristic curve was 0.94.

CONCLUSION

These results suggest that the measurement of BNP levels can help clinicians in the diagnosis of HF with preserved LVSF. Whether BNP levels might be used in clinical practice as a test for the diagnosis of HF with preserved LVSF is a question that merits further studies.

Assessment of a rapid HIV test strategy during labor: a pilot study from Rio de Janeiro, Brazil

OBJECTIVES

To use two rapid human immunodeficiency virus (HIV) tests at labor, measure test acceptance and performance, and measure HIV prevalence in these women.

METHODS

Between February and October 2000, two rapid tests (Determine; Abbott, Chicago, IL, U.S.A. and Double Check; Orgenics, Yavne, Israel) were used in three public maternities in Rio de Janeiro, Brazil. Enzyme-linked immunosorbent assay (ELISA) and Western blot (WB) analysis confirmed positive and discordant results.

RESULTS

Of the 858 patients who were enrolled, the mean gestational age was 36 weeks (median = 39, mode = 40) and 17 (2%) refused testing. Of the 841 patients tested, 13 were positive by both tests, which represents a 1.5% prevalence (95% confidence interval: 0.7%-2.3%); all were confirmed by ELISA and WB analysis. Seven samples gave discordant results by the rapid tests; of these, six were ELISA-negative/WB-negative and one was ELISA-negative/WB-indeterminate. The positive predictive value for samples that were positive by both rapid tests simultaneously was 100%.

CONCLUSIONS

Two rapid HIV tests used at labor were well accepted (98%). When the combined results of the two rapid tests (but not a single rapid test) were analyzed, this strategy was as efficient as the standard ELISA and WB HIV strategy for correctly classifying individuals.

Rhizobia of chickpea from southern Portugal: symbiotic efficiency and genetic diversity

AIMS

In order to evaluate differences between chickpea rhizobial populations from three geographical areas in southern Portugal (Beja, Elvas and Evora), isolates from the three regions were obtained and analysed.

METHODS AND RESULTS

The genetic characterization of the isolates was done by plasmid profiles and restriction analysis of the nifH gene. Symbiotic efficiency of the isolates was also determined. Relationships between geographical origin, symbiotic efficiency and molecular characteristics were established. Beja soil revealed a larger rhizobia population as well as the presence of some of the isolates with higher symbiotic efficiency values. Isolates with a single plasmid showed a significantly higher symbiotic efficiency.

CONCLUSION

Genetic and phenotypic differences were detected between the natural rhizobial populations from the three locations.

SIGNIFICANCE AND IMPACT OF THE STUDY

The different yield potential with cultivars of chickpea usually obtained in the three regions of southern Portugal could be due to their different natural rhizobial populations.

Mimicry of erythropoietin by a nonpeptide molecule

Erythropoietin (EPO) controls the proliferation and differentiation of erythroid progenitor cells into red blood cells. EPO induces these effects by dimerization of the EPO receptors (EPOR) present on these cells. To discover nonpeptide molecules capable of mimicking the effects of EPO, we identified a small molecule capable of binding to one chain of EPOR and used it to synthesize molecules capable of inducing dimerization of the EPOR. We first identified compound 1 (N-3-[2-(4-biphenyl)-6-chloro-5-methyl]indolyl-acetyl-L-lysine methyl ester) by screening the in-house chemical collection for inhibitors of EPO binding to human EPOR and then prepared compound 5, which contains eight copies of compound 1 held together by a central core. Although both compounds inhibited EPO binding of EPOR, only compound 5 induced dimerization of soluble EPOR. Binding of EPO to its receptor in cells results in activation of many intracellular signaling molecules, including transcription factors like signal transducer and activator of transcription (STAT) proteins, leading to growth and differentiation of these cells. Consistent with its ability to induce dimerization of EPOR in solution, compound 5 exhibited much of the same biological activities as EPO, such as (i) the activation of a STAT-dependent luciferase reporter gene in BAF3 cells expressing human EPOR, (ii) supporting the proliferation of several tumor cell lines expressing the human or mouse EPOR, and (iii) the in vitro differentiation of human progenitor cells into colonies of erythrocytic lineage. These data demonstrate that a nonpeptide molecule is capable of inducing EPOR dimerization and mimicking the biological activities of EPO.

Randomized comparison between intravaginal misoprostol and dinoprostone for cervical ripening and induction of labor

OBJECTIVE

We sought to evaluate the efficacy and safety of intravaginal misoprostol and dinoprostone for labor induction.

STUDY DESIGN

One hundred eighty-nine women with singleton term pregnancies and unfavorable cervices were randomly assigned to receive intravaginal misoprostol or dinoprostone. The outcome variables were change in Bishop score, time from application to active phase of labor and delivery, fetal and maternal morbidity, and the incidence of cesarean deliveries.

RESULTS

The interval from application of the initial dose to the beginning of the active phase of labor was 9.8 +/- 5.8 and 14.2 +/- 10.2 hours (P <.01), and the interval from initial dose to delivery was 15.3 +/- 9.8 and 19.1 +/- 13.2 hours (P =.027) for the misoprostol and dinoprostone groups, respectively. There were no significant differences in Bishop score change, cesarean delivery rate, and the incidence of tachysystole, hypersystole, and hyperstimulation. No maternal and neonatal adverse effects were noted.

CONCLUSION

Intravaginal misoprostol is more effective than intravaginal dinoprostone for labor induction in low-risk patients at term with unfavorable cervices.

Detection of angiographic coronary restenosis after percutaneous transluminal coronary angioplasty (PTCA): usefulness of angina combined with rest electrocardiogram

PURPOSE

To evaluate the value of recurrent anginal symptoms combined with seriation of conventional EKG in detecting coronary restenosis (renarrowing > or = 50% at the site dilated) after PTCA. Two hundred and seventy patients (204 men, mean age 53.1 +/- 9.4 years) with angina who submitted to successful PTCA of single-vessel coronary disease were followed and restudied angiographically 5.2 +/- 1.6 months after the procedure. At any moment from PTCA to follow-up: 1) typical angina pectoris was classified as either absent or present; 2) a 12-lead EKG was classified as improved, unchanged or worsened in comparison with the EKG either before or early after PTCA on the basis of ST-T alterations; 3) all patients underwent coronariography and were then classified as either having or lacking restenosis. The sensitivity and predictive positive value of recurrent angina, worsened EKG, or both, in detecting restenosis were respectively: 74.6% and 68.6%, 44.3% and 85.3%, and 55.9 and 91.7%. The specificity and predictive negative value of no recurrence of angina, improved EKG, or both, in detecting the absence of restenosis were respectively: 85.8% and 89.1%; 69.6% and 91.0%; and 75.6% and 93.9%.

CONCLUSION

In single-vessel coronary disease, the detection of coronary restenosis after PTCA based on behavior of the symptoms plus rest EKG seriation shows acceptable degrees of sensitivity, specificity and mainly of predictive values when comparison with respective historical values of the ergometric test is considered.

Vaginal hysterectomy for correcting genital prolapse. Long-term evaluation

OBJECTIVE

To determine whether a transvaginal hysterectomy with anterior and posterior repair is effective in the long term in treating uterovaginal prolapse and stress urinary incontinence (SUI).

STUDY DESIGN

Seventy-four patients subjected to vaginal hysterectomy for the treatment of severe genital prolapse, on average five years before the study, were contacted by letter for evaluation. Four of these patients had died, and 47 (67.1%) responded to the letter. The mean age of the patients at the time of reevaluation was 66.1 +/- 10.6 years, and mean parity was 6.6 deliveries.

RESULTS

All patients but two presented some degree of genital prolapse at the time of reevaluation, with three cases of total vaginal vault prolapse. White patients (87.2%) predominated over African (black) patients (12.8%). SUI associated with prolapse persisted in 14 of the 20 patients, and 6 others had this complaint after surgical correction (22.2% of previously continent patients).

CONCLUSION

The rate of unsuccessful surgical correction of severe genital prolapse was very high (95.7%), and cure of SUI was low (30%), with SUI actually arising after surgical correction in 25% of continent patients. In addition to parity, there seems to be a racial factor linked to the onset and maintenance of this pathology, with a higher prevalence among white patients.