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941.
This study investigates discrepancy and congruence between doctors and patients in their beliefs about the need for medical treatment. One hundred seventy-six outpatients and 337 university students rated each of a set of 35 symptoms on the urgency with which they would seek medical advice were they experiencing that symptom. Sixty-six general practitioners rated the urgency with which a person experiencing that symptom should seek medical advice. These symptoms were classified as relatively serious or nonserious on the basis of ratings by a separate set of doctors. General practitioners perceived a greater overall need for treatment than did patients, but this difference was greater for nonserious than for serious symptoms. In fact patients perceived treatment to be more urgent for three serious symptoms, each potentially indicative of cancer. The observed pattern of doctor-patient discrepancies can be explained in terms of the availability heuristic. The role of this heuristic in the cognitive dynamics of doctor-patient relationships merits future attention.  相似文献   
942.
dwarf4 (dwf4) mutants of Arabidopsis display a dwarfed phenotype due to a lack of cell elongation. Dwarfism could be rescued by the application of brassinolide, suggesting that DWF4 plays a role in brassinosteroid (BR) biosynthesis. The DWF4 locus is defined by four mutant alleles. One of these is the result of a T-DNA insertion. Plant DNA flanking the insertion site was cloned and used as a probe to isolate the entire DWF4 gene. Sequence analysis revealed that DWF4 encodes a cytochrome P450 monooxygenase with 43% identity to the putative Arabidopsis steroid hydroxylating enzyme CONSTITUTIVE PHOTOMORPHOGENESIS AND DWARFISM. Sequence analysis of two other mutant alleles revealed deletions or a premature stop codon, confirming that DWF4 had been cloned. This sequence similarity suggests that DWF4 functions in specific hydroxylation steps during BR biosynthesis. In fact, feeding studies utilizing BR intermediates showed that only 22alpha-hydroxylated BRs rescued the dwf4 phenotype, confirming that DWF4 acts as a 22alpha-hydroxylase.  相似文献   
943.
Results of 884 first-time shunts inserted in the time period from 1958 to 1989 are retrospectively evaluated, 1) to perform a durability analysis of a shunt based on Kaplan-Meyer method, 2) to compare the rate of revision for ventriculo-atrial (VA) and ventriculo-peritoneal (VP) shunts, 3) to compare the durability of a VA shunt with a VP shunt and 4) to do a stratified durability analysis comparing the VA and VP shunts in relation to the following background variables: shunt type, time period and age of the patient. Furthermore the specific complications related to VA and VP shunts are identified based on findings in the literature. Overall one-year shunt durability is 57% and five-year shunt durability is 37%. The median shunt durability is 1.68 years. Revision rate is 51% for VA shunts and 38.5% for VP (p < 0.05). Shunt durability is longer for VP shunts though the difference is not significant (p < 0.1). By use of stratified analysis of shunt durability no differences however are found between the two shunting methods. Hence the apparent difference in revision rate between VA and VP shunts seems secondary to variations in follow-up time and variations in background variables. To supplement our statistical analysis we have performed a literature study to look at the specific complications associated with VA and VP shunts. It seems as if the specific complications in relation to the VA shunting method are more severe than in relation to the VP shunting method.  相似文献   
944.
The frequency of adrenocortical carcinoma was studied in a group of 311 incidentally discovered adrenal tumours. Clinical characteristics were also analysed. Ultrasound scan and computed tomography were the main imaging techniques used. Hormonal examinations were also carried out. The patients with an adrenal tumour diameter greater than or equal to 4.0 cm, and those with excess steroid production were recommended for surgery. Of 131 patients treated with surgery, adrenocortical carcinoma was diagnosed in 21 cases. The diameter of these tumours ranged between 3.2 and 20.0 cm. The majority of these were hormonally inactive, but, in some cases increased corticosteroid secretion was noted. In 17/21 patients, mitotane was administered following surgery, with a good response in 13 cases. These 21 cases were compared with a group of 51 patients with clinically overt adrenocortical carcinoma.  相似文献   
945.
AIMS: To evaluate abdomino-pelvic changes in patients who had total abdominal hysterectomy (TAH) and bilateral salpingo-oophorectomy (BSO) for stage I ovarian cancer. METHOD: The postoperative computed tomographic (CT) scans of 23 patients who had undergone TAH and BSO for stage I ovarian tumours between 3 and 14 weeks previously were assessed, providing there had been no treatment with chemotherapy or radiotherapy and that each patient had normal tumour marker (CA125) levels after surgery. After the CT scan patients were followed up and had no clinical or biochemical (CA125) evidence of relapse for a median of 27 months (range 11 to 78 months). The following sites were assessed by two observers: the vaginal vault, round ligaments, bladder, rectum, perirectal fat, pelvic sidewalls, omentum, surgical scar and abdominal wall. Any abnormality was recorded, with re-evaluation on follow-up CT scans in ten patients (between three and 17 months). RESULTS: The following abnormalities were seen: (1) Thickened round ligaments (n=12) with bulbous masses at the surgically transected ends (n=7). This was bilateral in eight patients. (2) Vaginal vault thickening (n=11) either uniform (n=6) or bulbous bilaterally (n=2) or unilaterally (n=3). (3) Subtle omental bed stranding or nodularity (n=11). (4) Peritoneal thickening underlying the scar (n=4). (5) Asymmetrical rectus abdominis muscles (n=3) adjacent to the surgical scar or thickened scar tissue in the anterior abdominal wall (n=4). No significant bladder, rectal, perirectal or nodal abnormalities were found. CONCLUSION: Pseudotumours at the transected ends of the round ligaments, or uniformly swollen round ligaments, may be identified in patients who have had TAH and BSO, as may vaginal vault thickening. Other changes which may be observed in the abdomen and pelvis are peritoneal thickening adjacent to the scar and omental bed stranding.  相似文献   
946.
OBJECTIVE: To evaluate the performance of two pulse oximeters in the measurement of arterial hemoglobin saturation in hypoxemic children. DESIGN: Prospective, repeated-measures observational study. SETTING: A 16-bed pediatric intensive care unit in a children's tertiary hospital. PATIENTS: Sixty-six patients with arterial saturation of <90%. INTERVENTIONS: Three arterial blood samples were taken from each subject during a 48-hr period. Pulse oximeter measurements of arterial saturation were compared with arterial saturation determined by cooximetry. MEASUREMENTS AND MAIN RESULTS: Arterial saturation was measured using one or both pulse oximeters (SpO2) and compared with the arterial hemoglobin saturation determined by cooximetry (SaO2). Sixty-two subjects were studied, using the Ohmeda pulse oximeter giving 185 data points (78 with saturations <75% [defined by the average of pulse oximeter and cooximeter]); 53 subjects were studied, using the Hewlett-Packard pulse oximeter yielding 155 data points (60 with saturations <75%). SpO2 ranged from 24% to 94%. Bias and precision of the Ohmeda pulse oximeter were -2.8% and 4.8% >75% and -0.8% and 8.0% <75%. Bias and precision of the Hewlett-Packard pulse oximeter were -0.5% and 5.1% >75% and 0.4% and 4.6% <75%. Intrapatient regression coefficient (r) for the differences between pulse oximeter and cooximeter was 0.58 for the Ohmeda and 0.59 for the Hewlett-Packard. Regression coefficients for predicting change in cooximeter value given a change in the Ohmeda pulse oximeter were 0.59 and 0.71 <75% and >75%, respectively. Similar coefficients for the Hewlett-Packard pulse oximeter were 0.50 and 0.70, respectively. CONCLUSION: The performance of the Ohmeda pulse oximeter deteriorated below an SpO2 of 75%. The Hewlett-Packard pulse oximeter performed consistently above and below an SpO2 of 75%. The ability of both pulse oximeters to reliably predict change in SaO2 based on change in pulse oximetry was limited. We recommend measurement of PaO2 or SaO2 for important clinical decisions.  相似文献   
947.
Anti-CD4 mAb-induced tolerance to transplanted tissues has been proposed as due to down-regulation of Thl cells by preferential induction of Th2 cytokines, especially IL-4. This study examined the role of CD4+ cells and cytokines in tolerance to fully allogeneic PVG strain heterotopic cardiac allografts induced in naive DA rats by treatment with MRC Ox38, a nondepleting anti-CD4 mAb. All grafts survived >100 days but had a minor mononuclear cell infiltrate that increased mRNA for the Thl cytokines IL-2, IFN-gamma, and TNF-beta, but not for Th2 cytokines IL-4 and IL-6 or the cytolytic molecules perforin and granzyme A. These hosts accepted PVG skin grafts but rejected third-party grafts, which were not blocked by anti-IL-4 mAb. Cells from these tolerant hosts proliferated in MLC and produced IL-2, IFN-gamma, and IL-4 at levels equivalent to naive cells. Unfractionated and CD4+ T cells, but not CD8+ T cells, transferred specific tolerance to irradiated heart grafted hosts and inhibited reconstitution of rejection by cotransferred naive cells. This transfer of tolerance was associated with normal induction of IL-2 and delayed induction of IFN-gamma, but not with increased IL-4 or IL-10 mRNA. Transfer of tolerance was also not inhibited by anti-IL-4 mAb. This study demonstrated that tolerance induced by a nondepleting anti-CD4 mAb is maintained by a CD4+ suppressor T cell that is not associated with preferential induction of Th2 cytokines or the need for IL-4; nor is it associated with an inability to induce Th1 cytokines or anergy.  相似文献   
948.
Converging beam collimator geometries offer improved tradeoffs between resolution and noise for single photon emission computed tomography (SPECT). The major factor limiting the resolution in SPECT is the collimator-detector response blurring. In order to compensate for this blurring it is useful to be able to calculate the collimator response function. A previous formulation presented a method for calculating the response for parallel and converging beam collimators that assumed that the shape of the holes did not change over the face of the collimator. However, cast collimators are fabricated using pins with a constant cross-section (shape perpendicular to the pin axis). As a result, due to the angulation of the pins, the holes made by these pins have shapes on the front and back faces of the collimator that change with position. This change in hole shape is especially pronounced when the angle between the collimator hole and the collimator normal is large, as is the case for half-fan-beam or short-focal-length collimators. This paper presents a derivation of a modification to the original method that accounts for the change in shape of the collimator holes. The method has been verified by comparing predicted line spread functions to experimentally measured ones for a collimator with a maximum hole angle of 35 degrees with respect to the normal. This formulation is useful for predicting the response of fan-beam collimators in the design process and for use in detector response compensation algorithms.  相似文献   
949.
950.
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