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Biomedical subjects

C Quick

Publications and source records attributed to C Quick.

15 recordsLinked to original sources
PubMed2004

Strategies to improve the effectiveness of abdominal aortic aneurysm screening programmes.

OBJECTIVE: Ruptured abdominal aortic aneurysms (rAAAs) occurring in patients with screen-detected aneurysms could be regarded as a failure of screening and reduce effectiveness of screening. To understand this issue, we studied the reasons why rAAAs occur in screened patients and estimated the cost-benefit ratio if these ruptures could be prevented. METHODS: All rAAAs occurring in the Huntingdon district in the UK during the study period (1991-2000) were traced via a combination of hospital admission, accident and emergency attendance, and intensive therapy unit admission records, operating theatre registers and post-mortem reports. Cross-referencing with the aneurysm-screening database identified those patients who had attended screening. Previously used cost-effectiveness models were used to estimate the cost benefits to screening. RESULTS: Ninety-three rAAAs occurred in men over the study period, of whom 23 (25%) had been invited for screening and 13 (14%) had accepted the invitation. All who had been screened (mean age 75 [65-82]) had abnormal aortic diameters (>30 mm) on their first scan. Of those invited, 10/23 (43%) did not attend their screening appointment, 4/23 (17%) were deemed not fit for open surgery, 4/23 (17%) ruptured whilst being assessed for aneurysm repair, 2/23 (9%) ruptured whilst under six-monthly surveillance, and 3/23 (13%) failed to attend scheduled six-monthly surveillance appointments. Reducing screened ruptures by one half could increase the cost-effectiveness of screening by 27%. CONCLUSION: There were no failures of the screening test. The benefits of aneurysm screening can be improved by increasing the uptake of screening, the compliance with surveillance, and by streamlining the work-up process before surgery.

Aged↗
PubMed2000

401(k) plan asset allocation, account balances, and loan activity in 1998.

The Employee Benefit Research Institute (EBRI) and the Investment Company Institute (ICI) have been collaborating for the past three years to collect data on participants in 401(k) plans. This effort, known as the EBRI/ICI Participant-Directed Retirement Plan Data Collection Project, has obtained data for 401(k) plan participants from certain of EBRI and ICI members serving as plan record keepers and administrators. The report includes 1998 information on 7.9 million active participants in 30,102 plans holding nearly $372 billion in assets. The data include demographic information, annual contributions, plan balances, asset allocation, and loans, and are broadly representative of the universe of 401(k) plans. The database also includes three years of longitudinal information on approximately 3.3 million participants. Key findings include: For all 401(k) participants in the 1998 EBRI/ICI database, almost three-quarters of plan balances are invested directly or indirectly in equity securities. Specifically, 49.8 percent of total plan balances are invested in equity funds, 17.7 percent in company stock, 11.4 percent in guaranteed investment contracts (GICs), 8.4 percent in balanced funds, 6.1 percent in bond funds, 4.7 percent in money funds, and 0.3 percent in other stable value funds. Participant asset allocation varies considerably with age. Younger participants tend to favor equity funds, while older participants are more disposed to invest in GICs and bond funds. On average, participants in their 20s have 62.1 percent of their account balances invested in equity funds, in contrast to 39.8 percent for those in their 60s. Participants in their 20s invest 4.7 percent of their assets in GICs, while those in their 60s invest 20.6 percent. Bond funds, which represent 4.7 percent of the assets of participants in their 20s, amount to 9.0 percent of the assets of participants in their 60s. Investment options offered by 401(k) plans appear to influence asset allocation. For example, the addition of company stock substantially reduces the allocation to equity funds and the addition of GICs lowers allocations to bond and money funds. The average account balance (net of plan loans) for all participants was $47,004 at year-end 1998, which is 26 percent higher than the average account balance at year-end 1996. The median account balance was $13,038 at year-end 1998. The balances, however, represent only amounts with current employers and do not include amounts remaining in the plans of prior employers. The average balances of older workers with long tenure indicate that a mature 401(k) plan program will produce substantial account balances. For example, individuals in their 60s with at least 30 years of tenure have average account balances in excess of $185,000. The ratio of account balance to 1998 salary varies with salary, increasing slightly as earnings rise from $20,001 to $80,000, and falling a bit for salaries greater than $80,000. The increase in ratio likely reflects a greater propensity of higher-income participants to save, whereas the decline after $80,000 results from contribution and nondiscrimination rule constraints.

Adult↗
PubMed1999

401(k) plan asset allocation, account balances, and loan activity.

The Employee Benefit Research Institute (EBRI) and the Investment Company Institute (ICI) have been collaborating for the past two years to collect data on participants in 401(k) plans. This effort, known as the EBRI/ICI Participant-Directed Retirement Plan Data Collection Project, has obtained data for 401(k) plan participants from certain of EBRI and ICI sponsors and members serving as plan recordkeepers and administrators. The report includes 1996 information on 6.6 million active participants in 27,762 plans holding nearly $246 billion in assets. The data include demographic information, annual contributions, plan balances, asset allocation, and loans, and are currently the most comprehensive source of information on individual plan participants. In 1996, the first year for which data are ready for analysis, the EBRI/ICI database appears to be broadly representative of the universe of 401(k) plans. Key findings include: for all participants, 44.0 percent of the total plan balance is invested in equity funds, 19.1 percent in employer stock, 15.1 percent in guaranteed investment contracts (GICs), 7.8 percent in balanced funds, 6.8 percent in bond funds, 5.4 percent in money funds, 0.8 percent in other stable value funds, and 1.0 percent in other or unidentified investments. This allocation implies that over two-thirds of plan balances are invested directly or indirectly in equity securities. Asset allocation varies with age. For instance, on average, individuals in their twenties invested 76.8 percent of assets in equities and only 22.1 percent in fixed-income investments. By comparison, individuals in their sixties invested 53.2 percent of their assets in equities and 45.9 percent of assets in fixed-income investments. Investment options offered by 401(k) plans appear to influence asset allocation. For example, the addition of company stock substantially reduces the allocation to equity funds and the addition of GICs lowers allocations to bond and money funds. Employer contributions in the form of company stock affect participant allocation behavior. Participants in plans in which employer contributions are made in company stock appear to decrease allocations to equity funds and to increase the allocation of company stock in self-directed balances. The average account balance (net of plan loans) for all participants is $37,323. The balances, however, represent only amounts with current employers and do not include amounts remaining in the plans of prior employers. Nor do the balances indicate what savings would be in a "mature" 401(k) plan program. The average balances of older workers with long tenure at one employer indicate that a mature 401(k) plan program will produce substantial account balances. For example, individuals in their sixties with at least 30 years of tenure have average account balances in excess of $156,000; those in their fifties have balances in excess of $117,000.

Data Collection↗
PubMed1999

DSM-IV AD/HD: confirmatory factor models, prevalence, and gender and age differences based on parent and teacher ratings of Australian primary school children.

Based on parent and teacher ratings of primary school children on a scale comprising the 18 DSM-IV AD/HD symptoms, this study used confirmatory factor analysis to compare three models: all items in one factor; inattention in one and hyperactivity and impulsivity items in a separate factor; and inattention, hyperactivity, and impulsivity items in three separate factors. It also examined the prevalence rates of the three AD/HD Types, and gender and age differences. Results supported both the two- and three-factor models, with the three-factor model only slightly better than the two-factor model. Based on parent-teacher agreement, the prevalence rates were 1.6, 0.2 and 0.6% for the Inattentive, Hyperactive-Impulsive, and Combined Types, respectively. Overall, the male to female ratio was 5: 1, and boys were rated higher than girls by both parents and teachers. Age differences were minimal. The implications of the findings in relation to some of the assumptions made in DSM-IV for AD/HD are discussed.

Age Factors↗
PubMed1998

NIRS: dose dependency of local changes of cerebral HbO2 and Hb with pCO2 in parietal cortex.

Regional cerebral oxygenated hemoglobin and total hemoglobin increased systematically with increasing depth of hypercapnia, but the concentration of deoxygenated hemoglobin remained relatively constant. Relative mean changes of oxygenated and total hemoglobin increased nearly linearly, corresponding to the characteristic increase of the cerebral vascular dilation with increasing depth of hypercapnia.

Animals↗
PubMed1988

Nasopharyngeal carcinoma in Saudi Arabia: a retrospective study of 166 cases treated with curative intent.

A retrospective review was performed of the medical records of 166 adult patients with biopsy-proven carcinomas of the nasopharynx treated with curative intent at King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia. All patients were treated between June 1975 and December 1985 using megavoltage therapy equipment. Most patients presented with advanced nodal disease: 23 patients (13.9%) were N0, 16 patients (9.6%) were N1, 29 patients (17.5%) were N2, and 98 patients (59%) were N3. The overwhelming majority of patients had nonkeratinizing lesions (158/166). At the time of analysis, mean follow-up time was 24.2 months (range 2-108). Actuarial curves are presented for local/regional control as a function of T-stage and N-stage and for survival and time to development of distant metastases as a function of N-stage. At 4 years local/regional control was 70% for T1 lesions, 59% for T2 lesions, 30% for T3 lesions, and 35% for T4 lesions. There was little correlation between local/regional control and N-stage being about 50% at 4 years for all nodal subgroups. Only six patients exhibited an isolated first failure in the regional nodes alone, whereas 60 patients failed initially at the primary site (either alone or in conjunction with a simultaneous nodal failure). The development of distant metastases correlated to some extent with nodal disease ranging from 20% at 4 years for T1/T2 N0 patients to 70% for patients who initially presented with N3 disease. Survival data was more difficult to obtain due to cultural biases in a medically unsophisticated patient population. True survival curves are bounded by calculating actuarial curves in two ways: death as the failure endpoint and death plus lost-with-active-disease as failure endpoints. In terms of the latter curves, at 4 years "survival" ranged from 39% for patients with T1/T2 N0 lesions to 23% for patients with N3 lesions.

Adult↗
PubMed1976

External fixation in maxillofacial surgery.

The role of external fixation in the treatment of facial fractures is well defined. If standard open reduction and internal fixation techniques do not yield a satisfactory result, external fixation techniques may be required. Open reduction has the advantage of effecting precise approximation of fragments. However, this type of fixation may be inadequate, either because no stable point is available or because the angle of traction involved in fixation may result in displacement of the reduced fracture and subsequent malunion. When the facial skeleton is fractured, it tends to collapse inward, and if injury is severe, an external traction point anterior, lateral, or superior to the facial skeleton may be required to obtain a satisfactory result. There are occasions when intermaxillary fixation may be inadvisable, and in these instances external fixation techniques may be an appropriate means of immobilization. Finally external fixation techniques may be required in instances in which massive tissue loss precludes the use of standard open reduction and internal fixation techniques. It must be reemphasized that the methods of external fixation described here are not meant to supplant the standard techniques of open reduction and interosseous wiring, but when judicially employed complement them in achieving the desired result of precise reduction and firm fixation of the fractured facial skeleton.

Fracture Fixation↗
PubMed1974

Effect of transfer factor therapy on mixed lymphocyte culture reactivity.

We have studied the effect of dialyzable transfer factor therapy on three patients with immunodeficiency disease and in one patient who demonstrated no evidence of deficiency of either humoral or cellular immunity. We found evidence for nonspecificity in the effect of transfer factor on mixed lymphocyte culture reactivity. The data suggest that in patients with immunodeficiency disease a maturation of lymphocytes may lead to a generalized increased immune responsiveness. More profoundly, our data show that transfer factor may induce changes in the expression of histocompatibility determinants. We observed changes in the expression of determinants capable of stimulating in the mixed lymphocyte culture reaction as well as an increase in the capacity of lymphocytes to respond.

Antigens, Bacterial↗