Search PubMed⌕ Search

Biomedical subjects

J Chu

Publications and source records attributed to J Chu.

At least 145 records · Page 8Linked to original sources
PubMed1988

Changing practice habits of King County obstetricians.

In 1987, all practicing King County, Washington obstetricians (N = 181) were surveyed to determine the impact of rising malpractice premium rates and the threat of litigation on their obstetric practices. Six percent of respondents anticipated closing their practices over the next year, which means an additional 520 deliveries will have to be absorbed into existing obstetric practices. Of the 71% who increased their professional fees in 1986, 90% attributed the increase to higher malpractice premiums and increased risk of litigation.

Adult↗
PubMed1987

Decreasing incidence of invasive cervical cancer in young women.

Although the overall incidence of invasive cervical cancer is decreasing, there is concern that the disease might be increasing in younger women. Analysis of data from the Cancer Surveillance System, a population-based cancer registry in western Washington, shows a decreasing incidence of cervical cancer in women of all ages.

Adult↗
PubMed1987

The effect of age on the care of women with breast cancer in community hospitals.

We studied the process of care received by 1,680 female breast cancer patients treated in 17 community hospitals. The probability of receiving various diagnostic, consultation, therapy, or rehabilitation services was almost always significantly associated with patient age for one or more disease stages. Most often there was a linear trend for older patients to receive fewer services (e.g., biopsies prior to definitive treatment, number of lymph nodes examined, chemotherapy, radiation therapy) but other age patterns also were found. Age was not significantly associated with clinical staging or estrogen receptors.

Adult↗
PubMed1987

Pre-operative isotope liver scanning in clinicopathological staging of patients with large bowel cancer.

Isotope liver scanning is an accurate technique for detecting liver metastases from large bowel cancer. In this retrospective study of patients who had a resection for bowel cancer, the accuracy of liver scanning was 95%. However, the scan accuracy as defined by median survival time was insufficient to detect liver metastases missed by the surgeon at operation and did not alter the clinicopathological stage of the patient's disease.

Actuarial Analysis↗
PubMed1987

Rising incidence of breast cancer among young women in Washington State.

The prevalence of several known or suspected risk factors for breast cancer is changing among young women. The time trend in incidence of breast cancer among young women in western Washington was analyzed as a possible predictor of trends in future incidence rates. Data were from the Seattle-Puget Sound Surveillance, Epidemiology, and End Results cancer registry. For women age 25-44 years (n = 1,869 cases), the incidence of breast cancer increased by 22% (P less than .001) between the time periods 1974-77 and 1982-84. The estimated annual increase was 2.5% (P less than .001). The increase in incidence over time appeared to be greater among those residing in low-income census tracts of urban counties and among black women. Possible relationships between the observed increase in rates and trends of risk factors for breast cancer are discussed.

Adult↗
PubMed1987

Progressive teflon denudation of the monopolar needle: effects on motor unit potential parameters.

This paper reports on the effects of an increase in size of the recording surface of monopolar needles on motor unit potentials (MUPs). The teflon coating of the TECA monopolar needles MG37 and MF37, commonly used in clinical electromyography, was progressively denuded to increase the length of the recording tip to 2, 3, 5, and 10 times the normal exposure, with resultant increase in the area of the recording portion. Low threshold MUPs obtained on minimal contraction from the tibialis anterior were analyzed for amplitude, duration, area, phases, turns, peak duration, and index. The amplitude and area of the MUP showed the most change, both decreasing with progressive denudation. The number of turns and phases were also reduced, more for the MF than for the MG needle. Duration, peak duration, and index showed insignificant changes. These findings give further support to the use of duration for representation of the MUP, since this is the most stable parameter even under poor recording conditions.

Action Potentials↗
PubMed1986

A practical method of delivering the posterior axillary boost for the treatment of patients with breast cancer.

A practical technique for delivery of the posterior axillary boost is reported. A standard breast board is modified to allow for treatment of all fields in a single clinical set-up, and the posterior boost is delivered through a cut-out in the breast board. This technique is simple, is efficient, and eliminates problems of patient positioning and daily reproducibility.

Axilla↗
PubMed1986

Spinal cord protection during radiation therapy.

Treating intrathoracic malignancies to high doses, particularly those of lung and esophagus, requires limiting the radiation dose delivered to the spinal cord. Several factors are important in determining the cord dose. These are: The distance from the block or collimator edge to the cord, the variation of dose with distance from the block or collimator edge and, the expected variation of this distance for clinical set-up from day-to-day. When treating with an oblique beam, the position of the cord may be difficult to identify. A technique for localizing the spinal cord on a simulator film at an arbitrary gantry angle is presented. The technique requires determination of distances from the central axis of the beam to the medial aspect of the pedicle and posterior vertebral body. These can readily be obtained from measurements on orthogonal, AP/PA and lateral isocentric simulator radiographs. A mathematical transformation is applied to determine the corresponding cord locations on the oblique radiographs for any arbitrary gantry angle. The accuracy of cord localization was within 2-3 mm with a precision of 2 mm for five physicians who used this technique. The beam edge characteristics for 60Co, 6 MV, and 10 MV teletherapy unit were measured for various depths and field sizes. For the 6 and 10 MV units, the beam penumbra is nearly independent of the field size, depth and field defining devices (inner and outer collimator jaws, trimmer bars, and shielding blocks). Because the beam penumbra is dependent on the design of the linear accelerator, its measurement should be made individually for each linear accelerator. Our preliminary data on patient positioning uncertainty did not exceed the 6-8 mm limit documented in the literature.

Humans↗
PubMed1985

Cloning and expression of the metE gene in Escherichia coli.

A lambda-transducing phage was isolated that contains the metE gene. This gene codes for N5-methyl-H4-folate:homocysteine methyltransferase (EC 2.1.1.14), an enzyme that catalyzes the terminal reaction in methionine biosynthesis. A 9.1-kb EcoR1 fragment of this phage, containing the metE gene, was then cloned into pBR325. This plasmid, pJ19, was used to transform Escherichia coli strain 2276, a metE mutant, and restore the MetE+ phenotype. Although the transformed cells produced large amounts of the metE protein in vivo, in vitro studies using pJ19 as template showed low synthesis of the metE protein.

Bacteriophage lambda↗
PubMed1985

Cancer incidence in Caucasians living in the Pacific Basin.

Variations in cancer incidence among whites in 1973-77 in 8 geographic areas of the Pacific Basin were compared. Substantial differences were found for the occurrences of lung cancer, cancer of the corpus uteri, and malignant melanoma. White women living in New Zealand and Australia had the lowest risk of developing lung cancer, whereas white men living in the western United States had the highest risk. Cancer of the corpus uteri occurred more commonly in the western United States than elsewhere in the Pacific Basin. Geographic areas located closest to the equator experienced the highest incidence of malignant melanoma. In all areas, the incidence rates of cancers of the lung and corpus uteri and malignant melanoma increased significantly between 1960-66 and 1973-77; after the mid-1970s, rates of cancer of the corpus uteri declined. The incidence of stomach cancer decreased in all areas. Although cervical cancer decreased in incidence over time for most women, it increased noticeably in young women. The incidence of breast cancer also rose during the 17-year period. In at least 1 geographic area, the observed increases in breast cancer incidence were confined to women under age 40.

Adult↗
PubMed1985

Rationale and design of cancer chemoprevention studies in Seattle.

Three cancer prevention trials are currently in their early phases at The Fred Hutchinson Cancer Research Center, the University of Washington School of Public Health and Community Medicine, and the Swedish Hospital. All 3 studies are randomized and placebo controlled. One large-scale study involves the daily administration of retinoids to persons with asbestos-related lung disease in an attempt toward reduction of their high risk for bronchogenic carcinomas and mesotheliomas. A second study involves administration of the same agents to long-term heavy smokers; a substantial feasibility and toxicity pilot study will precede a full-scale prevention trial. In the third trial, folic acid administration is evaluated in relation to the progression and regression of cervical dysplasia among women with abnormal Pap smears. We report here the rationale and the design for these 3 studies.

Asbestosis↗
PubMed1985

Changes in motor unit action potential parameters in monopolar recordings related to filter settings of the EMG amplifier.

We studied the effect of different electromyographic amplifier settings on various parameters of motor unit potentials (MUPs) as recorded by the monopolar needle. Of the four filter settings used--2Hz-10kHz, 20Hz-10kHz, 20Hz-2kHz and 500Hz-10kHz--2Hz-10kHz yielded longest duration recordings. Reductions of all parameters of the MUP except for phases and turns were demonstrated with the 500Hz-10kHz filter. No significant differences were noted between recordings obtained with 20Hz-10kHz and 20Hz-2kHz filters. Frequencies below 500Hz were more significant in determining the various parameters of the MUP than were those above 2kHz. Most suitable filter settings for recording MUPs were 2Hz-10kHz and 20Hz-10kHz. Measurements of MUPs were shown to be specific for a given filter setting.

Action Potentials↗