HIV-1 subtype is an independent predictor of reverse transcriptase mutation K65R in HIV-1 patients treated with combination antiretroviral therapy including tenofovir.

Subtype-dependent selection of HIV-1 reverse transcriptase resistance mutation K65R was previously observed in cell culture and small clinical investigations. We compared K65R prevalence across subtypes A, B, C, F, G, and CRF02_AG separately in a cohort of 3,076 patients on combination therapy including tenofovir. K65R selection was significantly higher in HIV-1 subtype C. This could not be explained by clinical and demographic factors in multivariate analysis, suggesting subtype sequence-specific K65R pathways.

Decreasing population selection rates of resistance mutation K65R over time in HIV-1 patients receiving combination therapy including tenofovir.

OBJECTIVES: The use of tenofovir is highly associated with the emergence of mutation K65R, which confers broad resistance to nucleoside/nucleotide analogue reverse transcriptase inhibitors (NRTIs), especially when tenofovir is combined with other NRTIs also selecting for K65R. Although recent HIV-1 treatment guidelines discouraging these combinations resulted in reduced K65R selection with tenofovir, updated information on the impact of currently recommended regimens on the population selection rate of K65R is presently lacking. METHODS: In this study, we evaluated changes over time in the selection rate of resistance mutation K65R in a large population of 2736 HIV-1-infected patients failing combination antiretroviral treatment between 2002 and 2010. RESULTS: The K65R resistance mutation was detected in 144 patients, a prevalence of 5.3%. A large majority of observed K65R cases were explained by the use of tenofovir, reflecting its wide use in clinical practice. However, changing patterns over time in NRTIs accompanying tenofovir resulted in a persistent decreasing probability of K65R selection by tenofovir-based therapy. The currently recommended NRTI combination tenofovir/emtricitabine was associated with a low probability of K65R emergence. For any given dual NRTI combination including tenofovir, higher selection rates of K65R were consistently observed with a non-nucleoside reverse transcriptase inhibitor than with a protease inhibitor as the third agent. DISCUSSION: Our finding of a stable time trend of K65R despite elevated use of tenofovir illustrates increased potency of current HIV-1 therapy including tenofovir.

An exploratory survey of professionals on the use of stored tissue samples from minors for genetic research.

he ethical aspects of the use of stored tissue samples collected from minors are of topical interest. However, the views of professionals working in the field of genetics have not been investigated in depth anywhere. We conducted a survey among 194 such professionals in Belgium. This list was composed of the members of the High Council for Anthropogenetics, supplemented with all professionals working in the field of genetics that we found on the websites of the eight Belgian centers of human genetics and of the associated university registries. We achieved a response rate of 35.5%. The vast majority (92%) think that research on stored tissue samples is useful. Most respondents stated that parental consent is valid (82.5%), and 76.5% thought that children should also be given the right to assent when they are able to comprehend the implications of the storage of biological samples and of genetic research. Slightly more than half put the age at which young people can understand storage or research rather high: 16-18 years (51 and 53.1%, respectively). Although there is some consensus in the literature that donors should be allowed to give broad consent for future research on their biological samples, only 47.6% in our survey thought that parents should be allowed to consent to any future research on their children's samples. The aim of our study was to give some basis for future ethical reflections and policies on the subject of stored tissue samples from minors for genetic research. We concluded that a large majority of Belgian researchers and clinicians in the field of genetic research think research on stored tissue samples from minors is useful. They also think that parental consent for such research is valid, but that children should be allowed to assent as they grow older.

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.

Impaired endothelium-dependent cholinergic coronary vasodilation in patients with angina and normal coronary arteriograms.

The coronary vasomotor responses to selective infusion of graded concentrations (10(-6) to 10(-4) M) of acetylcholine into the left anterior descending artery were assessed by quantitative coronary arteriography in 24 patients with normal coronary arteriograms (12 patients with atypical symptoms and 12 patients with typical anginal pain) and 36 patients with coronary artery disease with different degrees of atherosclerosis of the left anterior descending artery. In the patients with normal coronary arteries and atypical chest pain, acetylcholine induced predominantly a vasodilator response, which was maximal during a 10(-5) M acetylcholine infusion. In contrast, in patients with coronary artery disease, acetylcholine caused dose-dependent vasoconstriction, which was observed even if the left anterior descending artery itself was smooth. Marked vasoconstriction was also induced in the patients with typical anginal pain and angiographically normal coronary arteries. In nine of these patients, this constrictor response was associated with anginal pain and electrocardiographic evidence of myocardial ischemia. Intracoronary administration of isosorbide dinitrate (1 mg) relieved the anginal pain and dilated all vessels. These data suggest that 1) patients with normal coronary arteriograms and angina pectoris manifest impairment of endothelium-dependent vasodilation similar to that observed in patients with overt coronary atherosclerosis; and 2) abnormal coronary vasoconstrictor responses resulting from this impairment may contribute to the pathogenesis of myocardial ischemia and angina in these patients.

Coronary flow reserve during coronary angioplasty in patients with a recent myocardial infarction: relation to stenosis and myocardial viability.

OBJECTIVES: In the present study, we examined post-stenotic coronary flow before and after percutaneous transluminal coronary angioplasty (PTCA) in patients with and without a recent myocardial infarction (MI) and related it to stenosis severity and residual viability. BACKGROUND: Post-stenotic coronary blood flow velocity reserve (CFVR) has been used with success to estimate functional stenosis severity in patients with stable angina. However, in patients with a recent MI, the impaired coronary vasodilator response of the reperfused myocardium may substantially alter the flow dynamics of the infarct-related artery. METHODS: Distal coronary flow velocities were recorded before and after PTCA in 36 patients at day 13 +/- 7 (mean +/- SD) after acute MI and in 38 patients without MI. The CFVR was assessed by the ratio of distal hyperemic to baseline average peak velocity, using a 0.014-in. Doppler guide wire. Stenosis severity was analyzed by quantitative coronary angiography, and infarct size was assessed scintigraphically. RESULTS: For similar angiographic stenosis severity, pre- and post-PTCA values of CFVR were significantly lower in patients with than without MI: 1.22 +/- 0.26 versus 1.50 +/- 0.45 before PTCA (p < 0.05) and 1.72 +/- 0.43 versus 2.21 +/- 0.74 after PTCA, respectively (p < 0.01). Although CFVR increased significantly (p < 0.0001) after angiographically successful PTCA in both study groups, abnormal CFVR (< or = 2.0) was still observed in 80% of patients with MI and in 44% of those without MI (MI vs. no MI, p = 0.001). Patients with an extensive infarction (relative infarct size > or = 50%) and those with a small infarction (relative infarct size < 50%) had comparable levels of post-PTCA CFVR (1.6 +/- 0.3 vs. 1.8 +/- 0.5, p = NS). Among a variety of factors, angiographic stenosis severity was the most important determinant of CFVR in both study groups. CONCLUSIONS: In patients with a recent MI, CFVR was significantly lower than in those without MI, both before and after PTCA. Besides the presence of this postreperfusion-related impairment of the coronary vasodilating response, CFVR was mainly influenced by stenosis severity and not by residual viability.

Optimization of a genotypic assay applicable to all human immunodeficiency virus type 1 protease and reverse transcriptase subtypes.

Genotypic assays are used often to guide clinicians in decisions concerning the treatment of patients. An optimized sequence-based genotypic assay was used to determine the whole protease and reverse transcriptase (RT) gene, including the gag cleavage site region and RNase H region. Since non-B subtypes are increasing in countries where subtype B was the most prevalent subtype, and treatment becomes more available in developing countries where the epidemic is characterized by a high prevalence of non-B subtypes, it was important that the genotypic test was evaluated using a panel of different subtypes. Amplification was successful for different subtypes: A, B, C, D, F, G, H, J, CRF01_AE, CRF02_AG, CRF11_cpx, CRF13_cpx and an uncharacterized recombinant sample. The detection limit of the PCR was 1000 copies/ml, except for 1 subtype C sample (PL3) and 1 CRF02_AG sample (PL8). The detection limit for these samples was 5000 copies/ml. A sequence could be obtained in both directions for most of the samples.

Adult Still's disease caused by Yersinia enterocolitica infection.

Clinical and biologic features of adult Still's disease developed in a patient who had high antibody titers against Yersinia enterocolitica during his illness. Immunocomplexes containing antibodies against Yersinia antigens were isolated at the beginning of the disease. Yersinia was not isolated from blood or stool specimens probably because we observed the patient during the secondary phase of the disease.

Paradoxic pulmonary vasoconstriction in response to acetylcholine in patients with primary pulmonary hypertension.

Pulmonary vascular reactivity was assessed during diagnostic heart catheterization in two patients with pulmonary hypertension unexplained by pulmonary or cardiac disease and in five patients with atypical chest pain and normal coronary arteriograms. Acetylcholine, an endothelium-dependent vasodilator that also has a direct contracting effect on vascular smooth muscle cells, was infused in the right atrium in a step-wise increasing dose in order to obtain final blood concentrations in the pulmonary circulation ranging from 10(-6) mol/L to 10(-4) mol/L. In the five control patients, acetylcholine induced a dose-related decrease of pulmonary vascular resistance (-52 percent +/- 9 percent). In the patients with primary pulmonary arterial hypertension, however, acetylcholine caused a paradoxic increase of pulmonary arterial pressure and of pulmonary vascular resistance. Thus, it appears that endothelium-dependent vasodilation is impaired in the pulmonary circulation of patients with primary pulmonary arterial hypertension. Endothelial dysfunction in the pulmonary circulation may play a role in the pathophysiology of this disease.

An outbreak of Burkholderia cepacia with septicemia on a cardiology ward.

During a 3-day period, eight patients developed septicemia with Burkholderia cepacia. Heparin injection was found to be a risk factor. Heparin was diluted with dextrose solution, which was aspirated from a 1-L bag. B cepacia, genotypically identical to the blood isolates, was isolated from this bag.

Comparison of guanabenz and clonidine in hypertensive patients.

The antihypertensive and clinical effects of two centrally acting drugs, guanabenz and clonidine, were compared in a double-blind trial in 29 patients with established hypertension. After a 1-week baseline period and 2 weeks on placebo, patients received treatment with either guanabenz (mean dose 24 mg daily) or clonidine (mean dose 0.45 mg daily) alone for 8 weeks. Both drugs produced equivalent and highly significant (p < 0.001) reduction in systolic and diastolic blood pressures in the standing and supine positions. They also reduced significantly the standing and supine pulse rates. Normal orthostatic responses were maintained with both regimens. All but 1 patient in each group reported side-effects during active treatment, the most frequent being dry mouth and sedation with each drug. No laboratory or ECG abnormalities related to treatment were observed.

Semi-automatic external defibrillation and implanted cardiac pacemakers: understanding the interactions during resuscitation.

Many emergency medical service (EMS) systems are currently implementing semi-automatic external defibrillation (AED) by emergency medical technicians. Surprisingly little information is available on the possible interactions between AEDs and implanted cardiac pacemakers. Therefore, at present there are no clear guidelines for the use of AEDs on patients having a cardiac pacemaker. During resuscitation, multiple interactions between pacemakers and AEDs are possible. External defibrillation can cause damage to several functions of the pacemaker. On the other hand, the presence of pacemaker spikes during cardiac arrest might prohibit recognition of the ventricular fibrillation by the AED. We report on two resuscitation attempts in which the interaction between the ventricular fibrillation, an implanted dual chamber pacemaker and the AED was decisive for the defibrillation success. A clear understanding of these possible interactions is necessary for the further refining of diagnostic algorithms and clinical strategies of prehospital defibrillation.

Prosthetic valve endocarditis due to methicillin-resistant Staphylococcus epidermidis and Micrococcus species successfully treated with rifampicin combined with other antibiotics.

Two patients with prosthetic valve endocarditis due to methicillin-resistant Gram-positive cocci (Staphylococcus epidermidis and Micrococcus spp.) are described. They were successfully treated with rifampicin combined first with an aminoglycoside and later with co-trimoxazole or co-trimoxazole plus vancomycin. The addition of rifampicin to these antibiotics resulted in enhanced serum bactericidal activity. High doses of rifampicin (1200-1800 mg) for 7-8 weeks did not cause any serious side-effect. Surgery was not required. During surveillance for more than 2 years endocarditis did not recur.

Indications for coronary arteriography after myocardial infarction.

The prognosis of patients after an acute myocardial infarction depends on the extent of the myocardial damage, its resulting left ventricular dysfunction and on the number and degree of narrowing of diseased coronary arteries. Patients with a severe multivessel disease constitute a high-risk group with an important morbidity and mortality during the first few months after hospitalization for a myocardial infarction. They could benefit from early revascularization therapy, whether by coronary artery bypass surgery, whether by percutaneous transluminal coronary angioplasty. Although early coronary revascularization is still controversial, management of patients after a myocardial infarction certainly will improve from a more accurate risk profiling by a careful diagnostic evaluation--including coronary arteriography in some subsets of patients--during the in-hospital period.

Review of the use of digitalis glycosides in ventricular dysrhythmia.

The present publication reviews actual knowledge of the electrophysiological properties of low doses of digitalis in perspective of its use in patients with ventricular dysrhythmia. Both animal experiments and observations in humans have demonstrated that increased adrenergic and decreased cholinergic tone predispose to ventricular arrhythmia. An increased cholinergic tone on the other hand has been shown to protect against increased ventricular vulnerability, especially in situations of increased adrenergic tone. Therefore the combination of the cholinergic and anti-adrenergic actions of digitalis may help to control situations of increased ventricular vulnerability. This principle is especially attractive because digitalis, in contrast to classical anti-arrhythmics is devoid of any cardiodepressive effects. The clinical experience with digitalis in ventricular dysrhythmia as documented by the group of Lown is discussed in detail. The studies presently available do not yet allow digitalis to be accepted as a drug of first choice in this indication, but its careful use is not longer to be rejected for patients with non-digitalis induced ventricular dysrhythmia.

Apical hypertrophic cardiomyopathy.

Illustrated by a case report, which was rather suggestive of coronary ischemic heart disease, the principle characteristics of apical hypertrophic cardiomyopathy are outlined. Outside East Asia, it remains a very uncommon variant of hypertrophic cardiomyopathy. The electrocardiogram in basal conditions showed giant negative T-waves (-14 mm) in the precordial leads, while the ventriculogram in RAO projection revealed the typical, so called "ace of spades" configuration. Based on the present literature and the follow-up of these patients a review of apical hypertrophic cardiomyopathy is presented. One of the most important consequences of the identification of this variant seems to be the rather good prognosis when compared to other forms of hypertrophic cardiomyopathy.

Myopotential inhibition of unipolar ventricular inhibited pacemakers: prevention by an insulating sheath.

To determine the occurrence of inhibition of pacing by sensing of myopotentials, forty-five patients with predominant pacemaker driven heart rhythm were studied. In eleven patients with a bipolar lead system myopotential inhibition was never observed. In the remaining group (34 patients) with unipolar pacemakers myopotential inhibition was demonstrated in fifteen patients. Three of them were symptomatic, two severely. In forty new implants a silicone-rubber insulating sheath was placed against the muscular side of the pacemaker. In none of these patients myopotential inhibition could be demonstrated. The authors conclude that myopotential inhibition occurs frequently in unipolar ventricular inhibited pacemakers, and can be prevented by insulating the muscular side of the anodal surface.

Angiographic coronary artery lesion morphology and pathogenetic mechanisms of myocardial ischemia in stable and unstable coronary artery disease syndromes.

The angiographic morphology of coronary artery stenoses was studied in 160 patients referred for diagnostic coronary arteriography. Three groups of patients were studied: 60 patients with stable angina, 78 patients with unstable angina and 22 patients with a recent myocardial infarction. Complex lesions were more frequently observed in patients with unstable angina (59%, p less than 0.001) and in patients with a recent myocardial infarction (54%, p less than 0.05) then in patients with stable angina (25%). Angiographic signs suggestive for the presence of intravascular thrombi were almost exclusively observed in the patients with unstable angina (34%, p less than 0.001) and in the patients with a recent myocardial infarction (27%, P less than 0.001) and were almost completely absent in the patients with stable angina (1.5%). The high prevalence of complex coronary artery lesion morphology and of intravascular thrombi observed in patients with unstable angina or with a recent myocardial infarction emphasizes the important role of intima disruption and of subsequent thrombosis in the pathogenesis of myocardial ischemia in those unstable syndromes of ischemic heart disease.

Idiopathic orthostatic hypotension and the Shy and Drager syndrome; Physiological studies in four cases; pathological report of one case.

Five cases of idiopathic orthostatic hypotension are presented. Physiological tests were performed in four cases which demonstrated that the lesion in the sympathetic system was most probably situated in the intermediolateral columns in three cases. In one case the lesion was localized on the efferent pathway either at the preganglionic or the postganglionic level. These four patients had also evidence of parasympathetic dysfunction. In the fifth case the clinical diagnosis of Shy and Drager syndrome was confirmed by pathological examination of the nervous system which revealed intermediolateral cell loss and the pathological findings commonly observed in the striato-nigral and olivo-ponto-cerebellar degenerations.

Cardiac manifestations of Becker-type muscular dystrophy.

The electro-, phonomechano- and echocardiographic manifestations observed in a family with documented X-linked Becker-type muscular dystrophy (BMD) are described. Important myocardial dystrophic lesions may occur in young patients with BMD. They are associated with typical electrocardiological findings which were described as a distinctive pattern in Duchenne-type muscular dystrophy. Myocardial involvement is seldom observed in heterozygotes for BMD.