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Biomedical subjects

R Reichle

Publications and source records attributed to R Reichle.

At least 19 recordsLinked to original sources
PubMed2006

Microfabricated surface-electrode ion trap for scalable quantum information processing.

Individual laser-cooled 24Mg+ ions are confined in a linear Paul trap with a novel geometry where gold electrodes are located in a single plane and the ions are trapped 40 microm above this plane. The relatively simple trap design and fabrication procedure are important for large-scale quantum information processing (QIP) using ions. Measured ion motional frequencies are compared to simulations. Measurements of ion recooling after cooling is temporarily suspended yield a heating rate of approximately 5 motional quanta per millisecond for a trap frequency of 2.83 MHz, sufficiently low to be useful for QIP.

Journal Article↗
PubMed2005

Creation of a six-atom 'Schrödinger cat' state.

Among the classes of highly entangled states of multiple quantum systems, the so-called 'Schrödinger cat' states are particularly useful. Cat states are equal superpositions of two maximally different quantum states. They are a fundamental resource in fault-tolerant quantum computing and quantum communication, where they can enable protocols such as open-destination teleportation and secret sharing. They play a role in fundamental tests of quantum mechanics and enable improved signal-to-noise ratios in interferometry. Cat states are very sensitive to decoherence, and as a result their preparation is challenging and can serve as a demonstration of good quantum control. Here we report the creation of cat states of up to six atomic qubits. Each qubit's state space is defined by two hyperfine ground states of a beryllium ion; the cat state corresponds to an entangled equal superposition of all the atoms in one hyperfine state and all atoms in the other hyperfine state. In our experiments, the cat states are prepared in a three-step process, irrespective of the number of entangled atoms. Together with entangled states of a different class created in Innsbruck, this work represents the current state-of-the-art for large entangled states in any qubit system.

Journal Article↗
PubMed2005

Long-lived qubit memory using atomic ions.

We demonstrate experimentally a robust quantum memory using a magnetic-field-independent hyperfine transition in 9Be+ atomic ion qubits at a magnetic field B approximately = 0.01194 T. We observe that the single physical qubit memory coherence time is greater than 10 s, an improvement of approximately 5 orders of magnitude from previous experiments with 9Be+. We also observe long coherence times of decoherence-free subspace logical qubits comprising two entangled physical qubits and discuss the merits of each type of qubit.

Journal Article↗
PubMed2001

Photodetachment of H- in a strong infrared laser field.

Negative hydrogen ions are exposed to a short infrared laser pulse of 2.15 microm wavelength and 250 fs duration. An imaging technique is used to record the energy resolved angular distribution of photoelectrons. The energy spectrum reveals at least three excess photon detachment channels. A quantum interference effect, resulting in an unusual dependence of the angular distribution on the electron kinetic energy, is most prominent in the lowest two-photon detachment channel. The appearance of this effect is discussed in terms of the threshold law of photodetachment.

Journal Article↗
PubMed1998

Familial aggregation of osteoarthritis: data from the Baltimore Longitudinal Study on Aging.

OBJECTIVE: To evaluate the familial aggregation of osteoarthritis (OA) in a cohort of healthy volunteers drawn from a community setting. METHODS: Hand radiographs obtained between 1978 and 1991 and bilateral standing knee radiographs obtained between 1984 and 1991 were read for changes of OA, using Kellgren-Lawrence (K-L) scales. The hand sites were distal interphalangeal (DIP) joints, proximal interphalangeal (PIP) joints, and first carpometacarpal (CMC1) joints. For each joint group, the presence of OA in at least 1 joint in a joint group, the number of affected digits in each joint group, and the sum of the K-L grade across all joints were analyzed. Polyarticular OA was recorded if there were OA findings in 2 of 3 hand joint groups plus 1 or both knees. Data from 167 families with hand radiographs, 157 families with knee radiographs, and 148 families with both hand and knee radiographs were analyzed for sib-sib correlations. RESULTS: After adjustment for age, sex, and body mass index, clinically relevant sib-sib common correlations were found for OA of the DIP, PIP, and CMC1 joints, for OA at 2 or 3 hand sites, and for polyarticular OA (r = 0.33-0.81) when OA was defined according to the number of affected joints or as the sum of the K-L grade across all joints. CONCLUSION: These results from a cohort of volunteers drawn from a community setting and ascertained without regard to OA status demonstrate familial aggregation of OA and contribute to the evidence for heritability of OA.

Adult↗
PubMed1996

Association of hand and knee osteoarthritis: evidence for a polyarticular disease subset.

OBJECTIVE: To examine the association between hand and knee osteoarthritis (OA) in a community based population. METHODS: Radiographs of 695 participants aged > or = 40 years in the Baltimore Longitudinal Study of Aging were read for changes of OA, using Kellgren-Lawrence grade > or = 2 as the case definition. RESULTS: Logistic regression analyses, adjusting for age, gender and body mass index, revealed a significant association between OA in the knee and the following joint groups: distal and proximal interphalangeal (DIP, PIP) and Hand2 (OA in two or more hand joint groups) for grade 2-4 and grade 3-4 disease, and the first carpometacarpal (CMC1) joint for grade 3-4 disease. CONCLUSION: There is an association between OA in hand sites and the knee. The strength of the associations increases with increasing disease severity. For the PIP site, there is a trend toward increasing strength of association for increasing numbers of affected joints and bilateral disease.

Adult↗
PubMed1996

Axial and hip bone mineral density and radiographic changes of osteoarthritis of the knee: data from the Baltimore Longitudinal Study of Aging.

OBJECTIVE: To examine the relationship between axial and hip bone mineral density (BMD) and radiographic changes of knee osteoarthritis (OA). METHODS: BMD of the lumbar spine and/or right hip was measured, using dual photon absorptiometry, in 402 men and 247 women in the Baltimore Longitudinal Study of Aging who had bilateral standing knee radiographs taken between 1984 and 1991. Radiographs were read for features of OA using Kellgren-Lawrence and reliable individual feature scales. The relationship between BMD and radiographic changes of OA was examined using multiple linear regression adjusting for age, body mass index, and smoking. Additional analyses with adjustment for menopausal status and estrogen replacement therapy were performed in a subset of women. RESULTS: Adjusted mean lumbar spine BMD was higher in subjects with knee osteophytes in both sexes: 1.23 +/- 0.02 vs 1.18 +/- 0.01 g/cm2 (p = 0.02) in men, and 1.12 +/- 0.02 vs 1.08 +/- 0.01 g/cm2 (p = 0.07) in women. There were no differences in levels of adjusted hip BMD by presence of any radiographic features of OA in either men or women. CONCLUSION: These results show that both men and women with radiographic changes of knee OA, specifically osteophytosis, have higher levels of adjusted spine but not hip BMD.

Adult↗
PubMed1995

Association of radiographic features of osteoarthritis of the knee with knee pain: data from the Baltimore Longitudinal Study of Aging.

OBJECTIVE: To examine the association between self-reported knee pain and radiographic features of osteoarthritis (OA) of the knee. METHODS: A sample of participants in the Baltimore Longitudinal Study of Aging (452 Caucasian males and 223 Caucasian females) completed questionnaires and underwent a standing radiograph of both knees at the same biennial visit between 1984 and 1989. Radiographs were interpreted using both the Kellgren-Lawrence and individual features scales. Odds ratios were calculated for the association of radiographic features with knee pain after adjustment for age, sex, and body mass index. RESULTS: Overall, 156 (23%) persons reported ever having knee pain, and 104 (15%) reported current knee pain (within the previous year). Both ever knee pain and current knee pain were significantly associated with the presence of definite knee OA (Kellgren-Lawrence grade > or = 2) and with the presence of all individual features. There was a direct relationship between all measures of severity of radiographic OA and knee pain. CONCLUSION: These data demonstrate that radiographic features of knee OA are significantly associated with knee pain. The data also support the continued use of the Kellgren-Lawrence grading scale for defining knee OA in population studies.

Adult↗
PubMed1995

Upper extremity bone mass and osteoarthritis of the knees: data from the Baltimore Longitudinal Study of Aging.

To examine the association of upper extremity bone mass with osteoarthritis (OA) of the knee, bilateral standing knee radiographs, taken between 1985 and 1991, in 430 Caucasian male and 266 Caucasian female subjects aged 40 years and above in the Baltimore Longitudinal Study of Aging, were read by one investigator for grade of OA using Kellgren-Lawrence scales. Several measures of upper extremity bone mass, size, and density, including combined cortical thickness (CCT), total width and percentage of cortical area of the second metacarpal, and bone mineral content (BMC), width, and density of the distal third of the left radius measured with single photon absorptiometry, were assessed at the same visit. In univariate analyses, men and women with definite knee OA were significantly older, men had significantly greater radial width, and women had significantly lower bone mass as measured by both CCT and BMC. After adjustment for age and body weight, however, men with knee OA had significantly higher BMC and radial width while neither of these measures of upper extremity bone mass and size was significantly associated with the presence of definite knee OA in women. Neither measure of upper extremity bone density was significantly associated with definite knee OA in either sex. These data suggest that, although men (but not women) with definite knee OA have significantly higher levels of adjusted radial bone mass and size, subjects with knee OA do not have significantly higher levels of adjusted bone mineral density at either upper extremity site.

Adult↗
PubMed1995

Imaging of intrahepatic cholangiocarcinoma: 1. Peripheral cholangiocarcinoma.

Cholangiocarcinoma is the second most common primary hepatic malignant tumor after hepatocellular carcinoma, accounting for 5-30% of all primary hepatic malignant tumors [1]. Intrahepatic cholangiocarcinomas can be classified as peripheral cholangiocarcinoma, which originates from an interlobular biliary duct, or as hilar cholangiocarcinoma, which originates from a main hepatic duct or from the bifurcation of the common hepatic duct. Intrahepatic cholangiocarcinomas account for only about half of cholangiocarcinomas, and this pictorial essay focuses only on the peripheral form of the disease. Clinically, therapeutically, and radiologically, these two types of cholangiocarcinomas differ. Features suggestive of the diagnosis of peripheral cholangiocarcinoma can be shown by sonography, CT, and MR imaging. Cholangiography and angiography have a limited role in evaluating this neoplasm that manifests as a focal mass. This essay reviews the appearances of peripheral cholangiocarcinoma and discusses the various imaging techniques that can be used to evaluate this unusual tumor that is often resectable and potentially curable.

Adult↗
PubMed1995

Imaging of intrahepatic cholangiocarcinoma: 2. Hilar cholangiocarcinoma.

Hilar cholangiocarcinoma (also called Klatskin's tumor) is more common than peripheral cholangiocarcinoma. Sonography, CT, MR imaging, angiography, and cholangiography can suggest the diagnosis, but the major issue of imaging with this tumor is to determine whether the tumor is resectable. The anatomic location of hilar cholangiocarcinoma makes resection difficult, so that surgical exploration of patients with this condition should be undertaken only when preoperative evaluation has shown a potential for curative resection. Preoperative assessment of resectability of hilar cholangiocarcinoma is often extensive, requiring several types of imaging. This pictorial essay reviews the imaging features of hilar cholangiocarcinoma. The role of imaging in the preoperative planning, with specific emphasis on staging extent of disease, including hepatic and vascular involvement, is discussed and illustrated.

Adult↗
PubMed1995

The association of body weight, body fatness and body fat distribution with osteoarthritis of the knee: data from the Baltimore Longitudinal Study of Aging.

OBJECTIVE: To examine the association of body weight, body fatness, and body fat distribution with osteoarthritis (OA) of the knee. METHODS: Bilateral standing knee radiographs, taken between 1985 and 1991, of 465 Caucasian men and 275 Caucasian women subjects aged 40 and above in the Baltimore Longitudinal Study of Aging were read by one investigator for grade of OA using Kellgren-Lawrence scales. Measures of obesity, assessed at same visit as the last radiograph during this interval, included body mass index, percent body fat, and body fat distribution. RESULTS: Both men and women with definite knee OA had higher age adjusted mean levels of body mass index, while women only had higher age adjusted mean levels of percent body fat. Both women and men in the highest tertile of body mass index had significantly increased odds of both definite and bilateral knee OA; women in the middle and highest tertile of percent body fat had significantly increased odds of both definite and bilateral knee OA, and men in the highest tertile of waist-hip ratio had significantly increased odds of bilateral knee OA. After adjusting for body mass index, however, the association of percent body fat and waist-hip ratio with knee OA in women and men, respectively, was no longer significant. CONCLUSION: These data further extend observations that body weight is associated with both definite and bilateral knee OA in both sexes, and support a stronger contribution of mechanical as opposed to systemic factors to explain this association.

Adipose Tissue↗
PubMed1994

Serum levels of insulin-like growth factor in subjects with osteoarthritis of the knee. Data from the Baltimore Longitudinal Study of Aging.

OBJECTIVE: To examine the relationship between serum levels of insulin-like growth factor 1 (IGF-1) and osteoarthritis (OA) of the knee. METHODS: Serum IGF-1 levels were compared in 162 male and 101 female subjects age > or = 20 stratified by presence of radiographic changes of OA of the knee. RESULTS: Mean serum IGF-1 levels were significantly lower in subjects with knee OA; however, after adjustment for age-related changes in IGF-1 levels, these differences were no longer significant. CONCLUSION: These data fail to support the hypothesis that serum IGF-1 levels are reduced in subjects with OA of the knee independent of the known age-related changes in these levels.

Adult↗
PubMed1994

The relationship of age and gender to prevalence and pattern of radiographic changes of osteoarthritis of the knee: data from Caucasian participants in the Baltimore Longitudinal Study of Aging.

The aim of this study was to estimate the prevalence and pattern of radiographic changes of osteoarthritis (OA) of the knee by age and gender in Caucasian participants in the Baltimore Longitudinal Study of Aging. Bilateral standing weight-bearing radiographs of the knee in 547 male and 351 female subjects (aged 20 and above) were read for changes of knee OA using Kellgren-Lawrence and individual features scales. Prevalence of definite (Kellgren-Lawrence grade > or = 2 changes) knee OA increased with advancing age in both sexes. Approximately 50 percent in both sexes showed bilateral involvement. Men aged 59 and below were more likely to have unilateral impairment than men aged 60 and above; no such differences were found in females. These data demonstrate that age and gender influence both the prevalence and pattern of radiographic changes of knee OA.

Adult↗
PubMed1993

Reliability of grading scales for individual radiographic features of osteoarthritis of the knee. The Baltimore longitudinal study of aging atlas of knee osteoarthritis.

RATIONALE AND OBJECTIVES: The authors present an atlas of individual radiographic features of osteoarthritis of the knee and evaluate the inter- and intra-reader reliability of trained readers using this atlas. METHODS: Four trained readers graded 30 standing anterior-posterior knee radiographs for eight selected features of osteoarthritis (medial and lateral osteophytes, joint space narrowing, and sclerosis; osteophytes of the tibial spines and chondrocalcinosis) as well as the Kellgren-Lawrence global scale. Inter- and intra-reader reliability were calculated using intraclass correlation coefficients. RESULTS: For all features except sclerosis and osteophytes of the tibial spines, inter-reader reliability ranged from 0.63 to 0.83, whereas intra-reader reliability ranged from 0.82 to 0.95. CONCLUSION: Using this atlas, trained readers are reliable in measuring the presence and severity of individual radiographic features of osteoarthritis of the knee. This atlas should be useful in clinical and epidemiologic studies of osteoarthritis of the knee.

Adult↗
PubMed1990

Measurement of hepatocellular function with deconvolutional analysis: application in the differential diagnosis of acute jaundice.

A direct, noninvasive technique was developed to quantitate hepatocyte function with computer assessment of scintiscans obtained after administration of technetium-99m disofenin in 53 patients with acute jaundice: 32 patients with normal livers, 10 patients with acute biliary obstruction, and 11 patients with acute hepatocellular dysfunction. In all patients a final clinical diagnosis was obtained with follow-up for a minimum of 4 months and, in most patients with obstruction or dysfunction, with surgery, intraoperative cholangiography, ultrasound, and/or computed tomography. Heart (blood pool) and liver time-activity curves were generated for 32 minutes after intravenous injection of 5-15 mCi (185-555 MBq) of Tc-99m disofenin and were subjected to deconvolutional analysis to determine the first-pass hepatocyte extraction fraction (HEF) of the tracer. The difference in HEF between patients with obstruction and those with dysfunction was highly significant (P = 3.3 X 10(-19)). Deconvolutional analysis eliminates the effects of tracer recirculation, thus permitting direct measurement of hepatic disofenin extraction, and appears to provide functional information useful in evaluation of the patient with acute jaundice.

Acute Disease↗
PubMed1987

Quantitative scintigraphy with deconvolutional analysis for the dynamic measurement of hepatic function.

A mathematical technique known as deconvolutional analysis was used to provide a critical and previously missing element in the computations required to quantitate hepatic function scintigraphically. This computer-assisted technique allowed for the determination of the time required, in minutes, of a labeled bilirubin analog (99mTc-disofenin) to enter the liver via blood and exit via bile. This interval was referred to as the mean transit time (MTT). The critical process provided for by deconvolution is the mathematical simulation of a bolus injection of tracer directly into the afferent blood supply of the liver. The raw data required for this simulation are obtained from the intravenous injection of labeled disofenin, a member of the HIDA family of radiopharmaceuticals. In this study, we perform experiments which document that the simulation process itself is accurate. We then calculate the MTT under a variety of experimental conditions involving progressive hepatic ischemia/reperfusion injury and correlate these results with the results of simultaneously performed BSP determinations and hepatic histology. The experimental group with the most pronounced histologic findings (necrosis, vacuolization, disorganization of hepatic cords) also have the most prolonged MTT and BSP half-life. However, both quantitative imaging and BSP testing are able to identify milder degrees of hepatic ischemic injury not reflected in the histologic evaluation. Quantitative imaging with deconvolutional analysis is a technique easily adaptable to the standard nuclear medicine minicomputer. It provides rapid results and appears to be a sensitive monitor of hepatic functional disturbances resulting from ischemia and reperfusion.

Animals↗