Coherent singlet-triplet oscillations in a silicon-based double quantum dot.

Silicon is more than the dominant material in the conventional microelectronics industry: it also has potential as a host material for emerging quantum information technologies. Standard fabrication techniques already allow the isolation of single electron spins in silicon transistor-like devices. Although this is also possible in other materials, silicon-based systems have the advantage of interacting more weakly with nuclear spins. Reducing such interactions is important for the control of spin quantum bits because nuclear fluctuations limit quantum phase coherence, as seen in recent experiments in GaAs-based quantum dots. Advances in reducing nuclear decoherence effects by means of complex control still result in coherence times much shorter than those seen in experiments on large ensembles of impurity-bound electrons in bulk silicon crystals. Here we report coherent control of electron spins in two coupled quantum dots in an undoped Si/SiGe heterostructure and show that this system has a nuclei-induced dephasing time of 360 nanoseconds, which is an increase by nearly two orders of magnitude over similar measurements in GaAs-based quantum dots. The degree of phase coherence observed, combined with fast, gated electrical initialization, read-out and control, should motivate future development of silicon-based quantum information processors.

Reduced Sensitivity to Charge Noise in Semiconductor Spin Qubits via Symmetric Operation.

We demonstrate improved operation of exchange-coupled semiconductor quantum dots by substantially reducing the sensitivity of exchange operations to charge noise. The method involves biasing a double dot symmetrically between the charge-state anticrossings, where the derivative of the exchange energy with respect to gate voltages is minimized. Exchange remains highly tunable by adjusting the tunnel coupling. We find that this method reduces the dephasing effect of charge noise by more than a factor of 5 in comparison to operation near a charge-state anticrossing, increasing the number of observable exchange oscillations in our qubit by a similar factor. Performance also improves with exchange rate, favoring fast quantum operations.

Multicentric performance analysis of HCV quantification assays and its potential relevance for HCV treatment.

An accurate quantification of low viremic HCV RNA plasma samples has gained importance since the approval of direct acting antivirals and since only one single measurement predicts the necessity of a prolonged or shortened therapy. As reported previously, HCV quantification assays such as Abbott RealTime HCV and Roche COBAS AmpliPrep/COBAS TaqMan HCV version 2 (CTM v2) may vary in sensitivity and precision particularly in low-level viremia. Importantly, substantial variations were previously demonstrated between some of these assays compared to the Roche High Pure System/COBAS TaqMan assay (HPS) reference assay, which was used to establish the clinical decision points in clinical studies. In this study, the reproducibility of assay performances across several laboratories was assessed by analysing quantification results generated by six independent laboratories (3× RealTime, 3× CTM v2) in comparison with one HPS reference laboratory. The 4th WHO Standard was diluted to 100, 25 and 10 IU/ml, and aliquots were tested in triplicates in 5 independent runs by each assay in the different laboratories to assess assay precision and detection rates. In a second approach, 2 clinical samples (GT 1a & GT 1b) were diluted to 100 and 25 IU/ml and tested as described above. While the result range for WHO 100 IU/ml replicates across all laboratories was similar in this analysis, the CVs of each laboratory ranged from 19.3 to 25.6 % for RealTime laboratories and were lower than CVs of CTM v2 laboratories with a range of 26.1-47.3 %, respectively, and also in comparison with the CV of the HPS reference laboratory (34.9 %). At WHO standard dilution of 25 IU/ml, 24 replicates were quantified by RealTime compared to 8 replicates with CTM v2. Results of clinical samples again revealed a higher variation of CTM v2 results as compared to RealTime values. (CVs at 100 IU/ml: RealTime: 13.1-21.0 % and CTM v2: 15.0-32.3 %; CVs at 25 IU/ml: RealTime 17.6-34.9 % and CTM v2 28.2-54.9 %). These findings confirm the superior precision of RealTime versus CTM v2 at low-level viremia even across different laboratories including the new clinical decision point at 25 IU/ml. A highly precise monitoring of HCV viral load during therapy will remain crucial for patient management with regard to futility rules, therapy efficacy and SVR.

Undoped accumulation-mode Si/SiGe quantum dots.

We report on a quantum dot device design that combines the low disorder properties of undoped SiGe heterostructure materials with an overlapping gate stack in which each electrostatic gate has a dominant and unique function-control of individual quantum dot occupancies and of lateral tunneling into and between dots. Control of the tunneling rate between a dot and an electron bath is demonstrated over more than nine orders of magnitude and independently confirmed by direct measurement within the bandwidth of our amplifiers. The inter-dot tunnel coupling at the [Formula: see text] charge configuration anti-crossing is directly measured to quantify the control of a single inter-dot tunnel barrier gate. A simple exponential dependence is sufficient to describe each of these tunneling processes as a function of the controlling gate voltage.

[Combined hepatitis A/B vaccination: evaluation of a vaccination schedule in facilities for handicapped people]. / Hepatitis A/B-Kombinationsimpfung: Evaluation eines Impfprogramms in Werkstätten für Menschen mit Behinderung.

AIM OF THE STUDY: People with mental and physical disabilities have a higher risk of infection with hepatitis viruses. Studies conducted so far show contradictory results on the success of vaccination in this population. These people live and work under special conditions and sometimes have immune defects. METHODS: We investigated the antibody response after combined vaccination against hepatitis A and B in facilities for handicapped people in the city of Essen/Germany. Antibodies were determined in people with disabilities (n=949) and also in social workers taking care of handicapped people (n=115). RESULTS: Protective antibodies against hepatitis A were detected in 98.9% in people with disabilities and social workers. The seroconversion rate against hepatitis B in handicapped people was 90.2% and was comparable to the seroconversion rate in social workers (91.3%). Re-vaccinations were offered to all people with anti-HBs titres below 100 IU/L (28% of handicapped and 23.5% of social workers). In the group of low responders in handicapped people about 50% developed anti-HBs concentration above 100 IU/L. Non-responders showed 30-40% seroconversion rate after re-vaccination. CONCLUSION: Based on this study we would recommend serological tests about 4-8 weeks after vaccination to confirm seroconversion. By this procedure people who need a booster vaccination will be recognized and non-responders should be offered another HBV vaccination. In about 20% of the non-responders included in this study HBs antigen was detected.

[Epidemiology of hepatitis A, B, and C among adults in Germany: results of the German Health Interview and Examination Survey for Adults (DEGS1)]. / Die Seroepidemiologie der Hepatitis A, B und C in Deutschland: Ergebnisse der Studie zur Gesundheit Erwachsener in Deutschland (DEGS1).

Ten years after seroepidemiological data were obtained in the German National Health Interview and Examination Survey 1998 (GNHIES98), German Health Interview and Examination Survey (DEGS1) data contribute to a population-based, representative surveillance of hepatitis A and B immunity and of the serological markers for hepatitis C in Germany. The prevalence of antibodies against the hepatitis A virus is 48.6 %. In comparison to the situation 10 years ago, seroprevalence is significantly higher among 18- to 39-year-old adults and is significantly lower in those aged 50-79 years. The association between age and seroprevalence has changed, indicating a decrease in naturally acquired hepatitis A immunity. Individual and population immunity has to be achieved through vaccination. Prevalence of hepatitis B antibodies indicates that 5.1 % of adults have been exposed to the virus, significantly fewer than 10 years ago (7.9 %). Prevalence of hepatitis B surface antibodies indicates that 22.9 % of adults have been vaccinated against hepatitis B. Vaccination coverage has increased in all age groups and is highest in the younger age groups. These positive trends can be attributed to the general recommendation since 1995 to vaccinate against hepatitis B. For hepatitis C, the prevalence of antibodies in the general population is 0.3 %. Germany thus remains a low-HCV-endemic country. An English full-text version of this article is available at SpringerLink as supplemental.

Management and outcomes after multiple corneal and solid organ transplantations from a donor infected with rabies virus.

BACKGROUND: This article describes multiple transmissions of rabies via transplanted solid organ from a single infected donor. The empirical Milwaukee treatment regimen was used in the recipients. METHODS: Symptomatic patients were treated by deep sedation (ketamine, midazolam, and phenobarbital), ribavirin, interferon, and active and passive vaccination. Viral loads and antibodies were continuously monitored. RESULTS: Recipients of both cornea and liver transplants developed no symptoms. The recipient of the liver transplant had been vaccinated approximately 20 years before transplantation. Two recipients of kidney and lung transplants developed rabies and died within days of symptomatic disease. Another kidney recipient was treated 7 weeks before he died. The cerebrospinal fluid viral load remained at constant low levels (<10,000 copies/mL) for approximately 5 weeks; it increased suddenly by almost 5 orders of magnitude thereafter. After death, no virus was found in peripheral compartments (nerve tissue, heart, liver, or the small intestine) in this patient, in contrast to in patients in the same cohort who died early. CONCLUSIONS: Our report includes, to our knowledge, the longest documented treatment course of symptomatic rabies and the first time that the virus concentration was measured over time and in different body compartments. The postmortem virus concentration in the periphery was low, but there was no evidence of a reduction of virus in the brain.

Analytical performance characteristics and clinical utility of a novel assay for total hepatitis C virus core antigen quantification.

The detection and quantification of hepatitis C virus (HCV) core antigen in serum or plasma by the use of different assay formats have previously been shown to represent useful markers of viral replication. In the present study, the intrinsic performance characteristics and the potential clinical utility of a novel assay for the quantification of total HCV core antigen were comprehensively assessed by using clinical serum samples and specimens contained in various evaluation panels. The Architect HCV Ag assay showed a specificity of 100%. The intra- and interassay coefficients of variation ranged from 3.6 to 8.0% and from 4.7 to 9.5%, respectively. Except for HCV genotype 2 isolates, the analytical sensitivity was always less than 10 fmol core antigen/liter, corresponding to approximately 500 to 3,000 IU of HCV RNA/ml. Linearity was guaranteed throughout the dynamic range (10 to 20,000 fmol/liter). When seroconversion panels were tested, the assay was not inferior to HCV RNA detection and reduced the preseroconversion period by 4 to 16 days. The results obtained by core antigen and HCV RNA quantification for 385 clinical specimens were correlated by regression analysis (r = 0.857), but the calculated conversion equation differed significantly from the line of identity. Monitoring of viral kinetics by use of either core antigen or RNA concentrations in 38 HCV-infected patients undergoing antiviral combination therapy resulted in very similarly shaped curves in all cases. Finally, the Architect HCV Ag assay was also shown to enable high-throughput screening of in vitro HCV RNA replication. With these results taken together, the Architect HCV Ag assay proved to be a specific, reproducible, highly sensitive, and clinically applicable test format which will find its future place in the context of virological HCV diagnostics.

Lack of de novo hepatitis C virus infections and absence of nosocomial transmissions of GB virus C in a large cohort of German haemodialysis patients.

To determine the prevalence and incidence of hepatitis C virus (HCV) infections among haemodialysis patients, a large prospective multicentre trial was conducted in the German Federal State of North Rhine-Westphalia. Sera obtained from the recruited patients in two separate sampling rounds run 1 year apart were analysed for both anti-HCV antibodies and HCV RNA. HCV RNA positive samples were also genotyped by direct sequencing of an HCV core fragment. In the first and second rounds, 150 (5.2%) of 2909 and 114 (5.4%) of 2100 patients were anti-HCV positive, respectively, and 4% of individuals were viraemic. Evaluation of potential risk factors in a case-control study indicated that the factors 'foreign country of birth', 'blood transfusions given before 1991' and 'duration of treatment on haemodialysis' were associated with the risk of HCV infection. Among the 2100 patients of whom 'paired' serum samples from both rounds were available for testing, not a single 'de novo' HCV infection could be recorded. The fact that in a subset of about 20% of these patients no nosocomial GB virus C (GBV-C) transmission occurred during the observational period suggests that the lack of HCV seroconversions was not only attributable to the isolation of HCV-infected patients but also to the strict adherence to so-called universal hygienic precautions for infection control maintained in the participating dialysis centres.

Transmission of hepatitis C virus in an orthopedic hospital ward.

Healthcare-associated infections with hepatitis C virus (HCV) hitherto have been observed mainly in hemodialysis settings as well as in hematology and oncology wards. In this communication, molecular and epidemiologic investigations to elucidate an HCV outbreak in an orthopedic ward are reported. One hundred and thirty-five patients hospitalized in the ward and 104 staff members were tested. In addition to extensive epidemiologic reviews and hygienic inspections, direct sequencing of HCV PCR fragments and phylogenetic analysis of more than 300 partial HCV sequences obtained by end-point limiting-dilution real-time PCR assay were carried out. Six patients were infected with very closely related HCV variants. Patient-to-patient spread of the virus was inferred to have started from one patient with previous HCV infection to the other five patients during their hospital stay. Inspections did not reveal substantial breaches in basic infection control practices and did not identify a specific activity that might have led to nosocomial transmission. As a result of the investigations, the hospital corrected the documentation of all medical and nursing activities undertaken in the ward, abandoned the use of all multidose saline and other medication vials, and included explicitly recommendations for the safe preparation and administration of injectable drugs into internal infection control guidelines. Thereafter, no further nosocomial transmissions of HCV have been recorded in the orthopedic ward. The events observed suggest that nosocomial transmission of HCV is not limited to hemodialysis, hematology or oncology settings, and they also reinforce the mandatory adherence to basic infection control practices.

Noradrenergic, but not cholinergic, deafferentation of prefrontal cortex impairs attentional set-shifting.

Both norepinephrine and acetylcholine have been shown to be critically involved in mediating attention but there remains debate about whether they serve similar or unique functions. Much of what is known about the role of these neurochemicals in cognition is based on manipulations done at the level of the cell body but these findings are difficult to reconcile with data regarding the unique contribution of cortical subregions, e.g. the dorsolateral prefrontal cortex, to attention. In the current study, we directly compared the effects of noradrenergic and cholinergic deafferentation of the rat medial prefrontal cortex, the homologue of primate dorsolateral prefrontal cortex, using an intradimensional/extradimensional attentional set shifting task, a task previously shown to be able to dissociate the function of the primate dorsolateral prefrontal cortex from orbitofrontal cortex. We found that noradrenergic, but not cholinergic, deafferentation produces specific impairments in the ability to shift attentional set. We also clarified the nature of the attentional deficits by assessing the ability of rats to disregard irrelevant stimuli. Noradrenergic lesions did not alter the ability of rats to ignore irrelevant stimuli, suggesting that the attentional deficit results from an overly focused attentional state that retards learning that a new stimulus dimension predicts reward.

Outcome of an exercise to notify patients treated by a general surgeon infected with the hepatitis C virus.

BACKGROUND: Health-care workers infected with the hepatitis C virus (HCV) and performing exposure-prone procedures may expose their patients to the risk of nosocomial HCV infection. OBJECTIVE: To assess the number of provider-to-patient transmissions of HCV among former patients of an HCV-infected general surgeon. RESULTS: The notification exercise covered 1461 individuals, on whom the surgeon performed 1683 operations. Eighty-two percent of these patients were tested for markers of HCV infection, and all but six subjects turned out to be not infected with the virus. Two of the anti-HCV positive patients were already infected before their operations, one individual was not available for further molecular analyses, and three subjects harboured HCV isolates that belonged to a different subtype (i.e. 1b) than the variant detected in the surgeon's serum. CONCLUSION: In this retrospective survey, no provider-to-patient transmission of HCV was detected among 1192 former patients of an infected general surgeon. This finding, one more time, suggests that such nosocomial transmission events are probably very rare. Consequently, recommendations for the management and guidance of HCV-infected health-care workers should carefully balance the workers' rights against justified patients' interests.

Towards a better resolution of hepatitis C virus variants: CLIP sequencing of an HCV core fragment and automated assignment of genotypes and subtypes.

Commercially available assays for typing of hepatitis C virus (HCV) isolates satisfy the current clinical needs. They are, however, limited in their ability to identify the multitude of existing HCV subtypes correctly. Therefore, these kits should only be used cautiously in epidemiological studies and will also not meet future clinical demands which might arise, e.g., from the application of HCV subtype-specific antiviral compounds. In an attempt to overcome the drawbacks of commercial typing procedures based on the analysis of the 5' untranslated region (5' UTR), an approach was developed which relies on CLIP sequencing of an HCV core fragment with automated assignments of types and subtypes via an originally created "core-specific" sequence database. The performance characteristics of the new technique were evaluated in comparison to the Trugene 5' NC Genotyping Kit. The core-based sequencing method could regularly detect HCV isolates of genotypes 1-6 with an analytical sensitivity of 5000 IU/ml. The accuracy of typing results obtained by the Trugene test was 97% (genotypes) and 81% (subtypes). The core-linked approach classified all HCV strains correctly on the level of genotypes and led to an adequate subtype assignment in 96% of all cases. This analytical performance characteristics recorded for the newly devised typing technique was superior to those reported for all commercially available assays, including a most recently released new generation of the line probe assay. Consequently, CLIP sequencing of an HCV core fragment with subsequent automated assignment of types and subtypes can be confidently used in clinical laboratory practice to answer current and also future questions in the context of HCV typing.

Homozygous hypobetalipoproteinemia: a disease distinct from abetalipoproproteinemia at the molecular level.

apoB DNA, RNA, and protein from two patients with homozygous hypobetalipoproteinemia (HBL) were evaluated and compared with normal individuals. Southern blot analysis with 10 different cDNA probes revealed a normal gene without major insertions, deletions, or rearrangements. Northern and slot blot analyses of total liver mRNA from HBL patients documented a normal size apoB mRNA that was present in greatly reduced quantities. ApoB protein was detected within HBL hepatocytes utilizing immunohistochemical techniques; however, it was markedly reduced in quantity when compared with control samples. No apoB was detectable in the plasma of HBL individuals with an ELISA assay. These data are most consistent with a mutation in the coding portion of the apoB gene in HBL patients, leading to an abnormal apoB protein and apoB mRNA instability. These results are distinct from those previously noted in abetalipoproteinemia, which was characterized by an elevated level of hepatic apoB mRNA and accumulation of intracellular hepatic apoB protein.

Genotyping of hepatitis C virus isolates by a new line probe assay using sequence information from both the 5'untranslated and the core regions.

The correct assessment of hepatitis C virus (HCV) genotypes and subtypes by commercial assays is of utmost importance mainly for the therapeutic management of patients suffering from HCV infections. In this study, the performance characteristics of a newly designed genotyping assay were evaluated that does not rely exclusively on sequence information derived from the 5'untranslated region but also takes into account part of the HCV core. One hundred and ten clinical specimens were tested by this new assay prior to its commercialisation. The obtained typing results were compared to those recorded by the 5'UTR-based Versant HCV Genotyping Assay, version 1, the core-related Gen-Eti K DEIA, and phylogenetic analyses of partial HCV core and NS5B sequences. The HCV genotypes and subtypes identified by the newly devised kit were completely in line with the assignments achieved by DEIA and phylogenetic analyses. In particular, all 64 HCV strains belonging to subtypes 1a or 1b were recognised correctly, and HCV 6e and 6f isolates were adequately assigned to subtypes 6c-l. Thus, the second generation of the Versant genotyping assay could overcome the drawbacks of its exclusively 5'UTR-based predecessor and will turn out to be a reliable tool for HCV typing in clinical laboratories.

A conserved 28-base-pair element (HF-1) in the rat cardiac myosin light-chain-2 gene confers cardiac-specific and alpha-adrenergic-inducible expression in cultured neonatal rat myocardial cells.

To study the transcriptional regulatory mechanisms which mediate cardiac-specific and inducible expression during myocardial cell hypertrophy, we have extensively characterized the rat cardiac myosin light-chain-2 (MLC-2) gene as a model system. The MLC-2 gene encodes a relatively abundant contractile protein in slow skeletal and cardiac muscle and is upregulated during in vivo cardiac hypertrophy and alpha-adrenergic-mediated hypertrophy of neonatal rat myocardial cells. In transient expression assays employing a series of MLC-2-luciferase constructs, recent studies have identified a 250-bp fragment which is sufficient for both cardiac-specific and alpha-adrenergic-inducible expression. Within this 250-bp fragment lie three regions (HF-1, HF-2, and HF-3), each greater than 10 bp in length, which are conserved between the chicken and rat cardiac MLC-2 genes, suggesting their potential role in the regulated expression of this contractile protein gene. As assessed by substitution mutations within each of the conserved regions, the present study demonstrates that HF-1 and HF-2 are important in both cardiac-specific and inducible expression, while HF-3 has no detectable role in the regulated expression of the MLC-2 gene in transient expression assays. HF-1 sequences confer both cardiac-specific and inducible expression to a neutral promoter-luciferase construct but have no significant effect in the skeletal muscle or nonmuscle cell contexts. Thus, these studies have identified a new cardiac-specific regulatory element (HF-1) which plays a role in both cardiac-specific and inducible expression during myocardial cell hypertrophy.

Integrins and the myocardium.

Extracellular matrix provides a structural, chemical, and mechanical substrate that is essential in cardiac development, growth, and responses to pathophysiological signals. Transmembrane receptors termed integrins provide a dynamic interaction of environmental cues and intracellular events. Integrins orchestrate multiple functions in the intact organism including organogenesis, regulation of gene expression, cell proliferation, differentiation, migration, and death. They are expressed in all cellular components of the cardiovascular system, including the vasculature, blood, cardiac myocytes and nonmuscle cardiac cells. The focus of this review will be on the role of integrins in the myocardium. We will provide background on integrin structure and function, discuss how the expression of integrins is critical to the form and function of the developing and postnatal myocardium, and review the known data on integrins as signaling molecules in the heart. Finally, we will offer insights to the future research directions into this important family of extracellular matrix receptors in the myocardium.

Impaired contractile performance of cultured rabbit ventricular myocytes after adenoviral gene transfer of Na(+)-Ca(2+) exchanger.

Na(+)-Ca(2+) exchanger (NCX) gene expression is increased in the failing human heart. We investigated the hypothesis that upregulation of NCX can induce depressed contractile performance. Overexpression of NCX was achieved in isolated rabbit ventricular myocytes through adenoviral gene transfer (Ad-NCX). After 48 hours, immunoblots revealed a virus dose-dependent increase in NCX protein. Adenoviral beta-galactosidase transfection served as a control. The fractional shortening (FS) of electrically stimulated myocytes was analyzed. At 60 min(-1), FS was depressed by 15.6% in the Ad-NCX group (n=143) versus the control group (n=163, P:<0.05). Analysis of the shortening-frequency relationship showed a steady increase in FS in the control myocytes (n=26) from 0.027+/-0.002 at 30 min(-1) to 0. 037+/-0.002 at 120 min(-1) (P:<0.05 versus 30 min(-1)) and to 0. 040+/-0.002 at 180 min(-1) (P:<0.05 versus 30 min(-1)). Frequency potentiation of shortening was blunted in NCX-transfected myocytes (n=27). The FS was 0.024+/-0.002 at 30 min(-1), 0.029+/-0.002 at 120 min(-1) (P:<0.05 versus 30 min(-1), P:<0.05 versus control), and 0. 026+/-0.002 at 180 min(-1) (NS versus 30 min(-1), P:<0.05 versus control). Caffeine contractures, which indicate sarcoplasmic reticulum Ca(2+) load, were significantly reduced at 120 min(-1) in NCX-transfected cells. An analysis of postrest behavior showed a decay of FS with longer rest intervals in control cells. Rest decay was significantly higher in the Ad-NCX group; after 120 seconds of rest, FS was 78+/-4% in control and 65+/-3% in the Ad-NCX group (P:<0.05) relative to steady-state FS before rest (100%). In conclusion, the overexpression of NCX in rabbit cardiomyocytes results in the depression of contractile function. This supports the hypothesis that upregulation of NCX can result in systolic myocardial failure.

Homozygous hypobetalipoproteinemia: transcriptional regulation and 5'-flanking sequence analysis in an apolipoprotein B deficiency state.

Apolipoprotein (apo) B is the principal apolipoprotein of chylomicrons, very-low-density lipoproteins (VLDL) and low-density lipoproteins (LDL). Patients with homozygous hypobetalipoproteinemia (HBL), characterized by apoB deficiency, have markedly decreased levels of hepatocyte mRNA as well as intracellular B apolipoprotein, and a virtual absence of plasma apoB. We have cloned, sequenced and analyzed the 5' regulatory region of the human apoB gene from -899 to +121 bp in normal and hypobetalipoproteinemic subjects. TATA and CAAT boxes were located at -30 and -61, respectively, and two GC-like boxes were identified at positions +56 and +108. The analysis of the HBL sequence revealed two substitutions at positions -838 and -517, when compared to the normal sequence. These substitutions were not present in any known apoB regulatory elements. The transcriptional activities of the homozygous hypobetalipoproteinemic and normal regulatory regions were compared by chloramphenicol acetyltransferase (CAT) assays in Hep G2 cells, and were found to be the same. Therefore, we conclude that the 5' regulatory region of the HBL apoB gene in this kindred is normal, and the two base substitutions do not affect promoter activity of the apoB gene. These studies suggest that a coding region abnormality in the apoB gene may lead to HBL.

Doppler echocardiographic analysis of left ventricular filling in treated hypertensive patients.

Early detection and prevention of cardiac dysfunction is an important goal in the management of hypertensive patients. In this study, Doppler echocardiography was used to evaluate the pattern of left ventricular diastolic filling in 38 subjects: 18 treated hypertensive patients (blood pressure 141 +/- 17/83 +/- 10 mm Hg, mean +/- SD) without other coronary risk factors and 20 risk-free normotensive subjects of similar age (47 +/- 10 and 49 +/- 13 years, respectively). Peak velocity of late left ventricular filling due to the atrial contraction was greater in hypertensive compared with normotensive subjects (69 +/- 14 versus 52 +/- 13 cm/s; p less than 0.001). Peak velocity of late filling was significantly greater in hypertensive versus normotensive subjects in those aged 50 years or younger and those older than age 50 (65 +/- 12 versus 50 +/- 11; p less than 0.01 and 75 +/- 15 versus 56 +/- 15 cm/s; p less than 0.05, respectively). In hypertensive subjects, peak velocity of late filling did not correlate with routine indexes of hypertensive heart disease (including posterior wall thickness and left ventricular mass), systolic and diastolic blood pressure or duration of hypertension. These results indicate that increased velocity of late left ventricular filling may be independent of left ventricular hypertrophy and persist despite effective blood pressure control.