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Biomedical subjects

W F Taylor

Publications and source records attributed to W F Taylor.

At least 55 records · Page 3Linked to original sources
PubMed1986

Lymphadenectomy in the management of stage I malignant melanoma: a prospective randomized study.

A prospective randomized study was initiated at our institution in 1972 to determine the efficacy of routine elective lymphadenectomy in localized (stage I) melanoma. Included in the study were 171 patients, 62 of whom had no lymphadenectomy, 55 of whom had delayed lymphadenectomy, and 54 of whom had immediate lymphadenectomy. No significant difference was found among the three treatment groups with respect to survival or metastasis-free survival. Multifactorial analysis indicated that the level of invasion and the thickness of the lesion were the most important prognostic factors, followed by age (60 years or older), site (legs), and tumor type (nodular). A prognostic index based on these variables was highly predictive of metastasis or death. Even when this score was considered, no significant variation was noted among the three treatment groups. More subsequent complications of melanoma, however, occurred in the group with no lymphadenectomy--36 in this group but only 19 in each of the other treatment groups. This finding was not statistically significant but does indicate that a few additional problems may be associated with leaving regional nodes intact. Further studies are needed, and indeed are being conducted, to determine whether elective lymphadenectomy improves survival sufficiently to offset the costs and the complications associated with this approach.

Adult↗
PubMed1986

Lung cancer screening: the Mayo program.

The National Cancer Institute has sponsored three randomized controlled trials of screening for early lung cancer in large, high-risk populations to determine whether lung cancer detection can be improved by adding sputum cytological screening every 4 months to chest roentgenography done either yearly or every 4 months; and lung cancer mortality can be significantly reduced by this type of screening program, followed by appropriate treatment. Results of the three trials suggest that sputum cytology alone detects 15% to 20% of lung cancers, almost all of which are squamous cancers with a favorable prognosis; and chest roentgenography may be a more effective test for early-stage lung cancer than previous reports have suggested. Nevertheless, results of the randomized trial conducted at the Mayo Clinic showed that offering both procedures to high-risk outpatients every 4 months conferred no mortality advantage over standard medical practice that included recommended annual testing.

Clinical Trials as Topic↗
PubMed1986

Effect of local warming on forearm reactive hyperaemia.

Measurement of minimal vascular resistance has proved useful in quantifying structural changes in regional circulations. Accurate measurement of minimal vascular resistance requires full relaxation of all resistance vessels within the region under examination. The usual procedure in humans involves the measurement of maximal forearm blood-flow following 6-10 min of forearm ischaemia. We conducted this study to find whether forearm skin was fully vasodilated by this procedure. Peak forearm blood-flow was measured by plethysmography in six healthy subjects following 10 min of ischaemia while the arm was at a neutral temperature (33 degrees C) and while the arm was locally warmed to 42 degrees C. Peak reactive hyperaemia blood-flow was significantly elevated by local heating (P less than 0.001) to 79.6 ml 100 ml-1 min-1 from a value of 50.2 ml 100 ml-1 min-1 during normothermia. Peak reactive hyperaemia blood-flow in the contralateral unheated forearm showed no significant change between the two periods of ischaemia (P greater than 0.05). These findings were confirmed in four subjects by laser Doppler velocimetry, which gives a linear index of skin blood-flow. In normothermic conditions, this index rose to 0.89 V following 10 min of ischaemia and to 1.26 V with local warming to 42 degrees C (P less than 0.001). Ischaemia plus local warming did not cause a further significant rise in this index of skin blood-flow (1.35 V, P greater than 0.05). These data suggest that 10 min of ischaemia during normothermia is insufficient to relax fully cutaneous resistance vessels and that maximal forearm blood-flow is underestimated by this procedure.

Adult↗
PubMed1985

Fecal blood levels in health and disease. A study using HemoQuant.

We tested HemoQuant, a quantitative assay of fecal blood based on the fluorescence of heme-derived porphyrin, in 106 healthy volunteers, 170 patients with gastrointestinal symptoms but with normal diagnostic studies, 44 patients with gastrointestinal cancer, 75 patients with benign polyps, and 374 patients with a variety of other benign gastrointestinal lesions, including ulcers and erosions. In 98 per cent of the healthy volunteers, fecal hemoglobin concentrations were less than 2 mg per gram of stool. Levels were similarly low in stools from patients with symptoms and normal studies and in patients with relatively minor benign lesions. Within these groups, levels were slightly higher in those who had ingested red meat or aspirin. The fecal hemoglobin concentration was higher in patients with gastrointestinal cancer than in any other group, and 97 per cent of those with colorectal cancer had levels above 2 mg per gram. The sensitivity of HemoQuant was significantly greater than that of the guaiac test Hemoccult, particularly when heme was degraded or stools were dry. Intestinal degradation of heme to porphyrin can be measured separately by HemoQuant, and was greater when bleeding was from proximal lesions rather than distal ones. We conclude that HemoQuant is a more sensitive measure of gastrointestinal bleeding than Hemoccult, and that its capacity to measure degraded heme may be useful in indicating the anatomic site of bleeding.

Evaluation Studies as Topic↗
PubMed1985

Is the BANS concept for malignant melanoma valid?

In this study of 427 patients with stage I malignant melanoma seen at the Mayo Clinic between 1973 and 1981, only those patients with complete data with respect to thickness and level of penetration of lesion, morphologic type, and anatomic site were included. Although supporting the widely accepted concept of the prognostic importance of thickness of the lesion, the level of penetration was of much lesser significance in our series, and prophylactic node dissection could not be shown to be of significant benefit. Likewise, the BANS concept proposed by Day et al [1] was not corroborated. The reasons for these discrepancies are not fully apparent, although a preponderance of thin and intermediate thickness lesions in our patients may have had some influence on our results.

Adolescent↗
PubMed1985

Intravesical thiotepa and mitomycin C treatment immediately after transurethral resection and later for superficial (stages Ta and Tis) bladder cancer: a prospective, randomized, stratified study with crossover design.

In a prospective, randomized, stratified study with crossover design the effect of thiotepa was compared to that of mitomycin C when each was instilled intravesically immediately at the end of complete removal of superficial bladder cancer (stages Ta and Tis) and later on tumor recurrence. The 3-month and 1-year rates free of recurrence were 93 and 78 per cent, respectively, for thiotepa (41 patients), and 97.6 and 67.1 per cent, respectively, for mitomycin C (42 patients) (p equals 0.6). On crossover (5 patients to thiotepa and 9 to mitomycin C) at 1 year 60 per cent of the patients receiving thiotepa secondarily and 51.9 per cent of those receiving mitomycin C secondarily were free of recurrence (p equals 0.52). Therefore, both drugs are equally effective in reducing bladder tumor recurrence. Future comparative studies should continue to include thiotepa as a standard by which the efficacies of other agents are judged.

Adult↗
PubMed1985

Trends and variability in survival among patients with osteosarcoma: a 7-year update.

This report is an update of a 1978 article on osteosarcoma in Mayo Clinic patients. It includes additional follow-up on previously reported cases and incorporates new cases treated since the time of that original study. From 1963 through 1981, 336 patients with classic, previously untreated osteosarcoma received their first definitive treatment at our institution. Survival of these patients was studied in detail. The most significant result was that survival in the 1960s was much worse than that in the 1970s. The first evidence of improvement in survival was noted in 1969; subsequently, further improvement occurred but was not consistent. This finding prevailed with respect to duration of survival to death, survival to detection of metastasis, and survival from occurrence of metastasis to death. On the basis of detailed regression analysis, several variables had independent prognostic value. From these findings, a prognostic score was developed, which was based on the number of the following unfavorable characteristics: age younger than 10 years, male sex, tumor diameter more than 15 cm, cell type osteoblastic or chondroblastic, duration of symptoms 2 months or less, and involvement of the femur or humerus. Patients with five or six of these unfavorable characteristics had a very poor survival; in contrast, patients with only one or two characteristics had a good outcome. Even when these scores were fairly constant, however, the calendar period had a strong influence on survival. Likewise, when treatment was considered and adjustments by score were made, no significant differences could be found between those patients treated by amputation only and those treated by amputation supplemented with chemotherapy or radiotherapy.

Adolescent↗
PubMed1985

Anaplastic carcinoma of the thyroid: a clinicopathologic study of 82 cases.

Anaplastic carcinoma of the thyroid accounts for about 10% to 15% of all thyroid carcinomas in the United States. Its lethality is evidenced by a 5-year survival rate of 3.6% and a median survival of 4 months. Rapid growth of a thyroid mass, frequently in a preexisting goiter, is the most common manifestation; the diagnosis should be considered and expeditiously pursued in all patients who present with this finding. Relatively favorable prognostic features seem to be unilateral tumors, a tumor diameter of less than 5 cm, no invasion of adjacent tissue, and absence of nodal involvement. For resectable lesions, thyroid lobectomy with wide margins of adjacent soft tissue on the side of the tumor seems to constitute a safe, appropriately aggressive surgical approach. Total thyroidectomy and radical neck dissection results in an increased complication rate and has no advantage over a more conservative approach. Radiotherapy, chemotherapy, immunotherapy, and combination radiotherapy and chemotherapy need further evaluation.

Adult↗
PubMed1985

Role of muscle mass and mode of contraction in circulatory responses to exercise.

The roles of the mode of contraction (i.e., dynamic or static) and the active muscle mass as determinants of the cardiovascular responses to exercise were studied. Six healthy men performed static handgrip (SHG), dynamic handgrip (DHG), static two-knee extension (SKE), and dynamic two-knee extension (DKE) to local muscular fatigue in approximately 6 min. Increases in mean arterial pressure were similar for each mode of contraction, 29 +/- 5 and 30 +/- 3 mmHg in SHG and DHG and 56 +/- 2 and 48 +/- 2 mmHg in SKE and DKE (P greater than 0.05) but larger for KE than HG (P less than 0.001). Cardiac output increased more for dynamic than for static exercise and for each mode more for KE than HG (P less than 0.001). Systemic resistance was lower for dynamic than static exercise and fell from resting levels by approximately 1/3 during DKE. The magnitude of the pressor response was related to the active muscle mass but independent of the contraction mode. However, the mode of contraction affected the circulatory changes contributing to the pressor response. Equalization of the pressor responses was achieved by proportionately larger increases in cardiac output during dynamic exercise.

Adult↗
PubMed1985

Mode of neural control mediating rat tail vasodilation during heating.

The purpose of this investigation was to delineate the mode of efferent neural control mediating rat tail vasodilation during body heating. Tail blood flow (venous occlusion plethysmography), tail skin temperature over the ventral vascular bundle, and arterial pressure were measured in Sprague-Dawley rats anesthetized with pentobarbital sodium (45 mg/kg). Three protocols were followed: anesthesia of the lumbar sympathetic chain, bilateral lumbar sympathectomy, and sympathetic nerve stimulation during varying degrees of alpha-adrenergic receptor blockade. Mean tail blood flow and tail vascular conductance (TVC) during body heating were 40.3 +/- 8.7 ml X 100 ml-1 X min-1 and 39.2 +/- 9.2 ml X 100 ml-1 X min-1 X 100 mmHg-1, respectively. Interruption of sympathetic nerve activity by sympathetic nerve anesthetization or sympathectomy during heat stress caused a nonsignificant increase in TVC to 112.7 +/- 1.8 and 121.12 +/- 6.3%, respectively, of the values achieved with body heating. Sympathectomy performed in normothermic animals that had recovered from prior heating caused an increase in TVC to 128.4 +/- 14.0% of the levels achieved during the previous heating period. In addition, sympathetic nerve stimulation after complete alpha-adrenergic receptor blockade failed to produce a vasodilation [control TVC = 10.2 +/- 3.9 vs. TVC during nerve stimulation = 10.4 +/- 3.9 (P greater than 0.05)]. It is concluded that the increase in TVC during body heating occurs solely via a reduction in vasoconstrictor nerve activity.

Animals↗
PubMed1985

Airline pilot disability: the continued experience of a major US airline.

This study details our continued experience with preemployment screening and medical disability in a large group of pilots from one airline from 1975 through 1982. During this period, 368 pilot applicants underwent preemployment screening and 73 of these were rejected for employment because of medical reasons. The majority (45) of these were unsuitable for psychological reasons. Medical disability accounted for approximately 20% of the pilots separated from the company during the period of study. Age-specific disability rates increased rapidly after age 45 years, with cardiovascular disease responsible for more than 50% of these medical losses. Disability rates of older pilots have decreased considerably compared with previous rates: the age-adjusted rate for pilots age 45 years or older has decreased from 27.50/1,000 person-years to 8.97/1,000 person-years (p less than 0.0001). The reasons for this reduction remain unclear, but changes in the interpretation of the Federal Aviation Administration regulations and changes in company policies may have contributed. The role of preventive medicine in the form of regular medical surveillance is uncertain, with no direct evidence of a beneficial effect.

Adult↗
PubMed1984

Antibody-dependent cellular cytotoxicity. Relation to stage and disease course in North American patients with nasopharyngeal carcinoma.

A prospective study of North American patients, mostly white, with different histopathologic types of nasopharyngeal carcinoma was initiated approximately five years ago. Several anti-Epstein-Barr virus (EBV) serologic tests are being evaluated; one is the antibody-dependent cellular cytotoxicity (ADCC) assay, which measures antibodies to an EBV-induced membrane antigen component. A low ADCC titer at diagnosis reflects a poor prognosis, and the determination of antibody titers by this assay identifies patients in whom recurrent disease is likely to develop after conventional radiation therapy for World Health Organization types 2 and 3 carcinomas. Of the patients who had high ADCC titers at diagnosis, 80% survived three years or longer, whereas 50% of the patients with low titers survived three years, and only 35% survived five years. High and low ADCC titers were seen in all stages (except in Ho stage V), and the distribution of patients by high and low ADCC titers was similar in each of the stage groupings. We conclude that the ADCC titer at the time of diagnosis is generally predictive of the prognosis. Clinical staging is the traditional approach for predicting prognosis, but determination of the ADCC titer can be used to segregate patients within the stage groups into those with "good" and "poor" prognoses. Serologic testing may eventually become one of the methods for staging patients with WHO types 2 and 3 nasopharyngeal carcinoma.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1984

Degradation of fenprostalene in polyethylene glycol 400 solution.

The kinetics of degradation of fenprostalene (I) in polyethylene glycol 400 solution was examined using HPLC. The degradation of I at 80 degrees C was shown to depend on the presence of oxygen and a large number of polar products were produced, as evidenced by using 3H-labeled I. Evidence that autoxidation of the polyethylene glycol 400 was concurrent with degradation of I was found from a drop in the apparent pH. Antioxidants were very effective in retarding the rate of degradation in the presence of oxygen. Degradation of I in polyethylene glycol 400 appears to arise from a reaction between the drug and reactive peroxide intermediates formed through air-oxidation of polyethylene glycol 400. This is supported by the finding that I reacts exclusively by a slow transesterification reaction in diethylene glycol, a solvent that is stable to autoxidation.

Chromatography, High Pressure Liquid↗
PubMed1984

Roentgenographically occult lung cancer: pathologic findings and frequency of multicentricity during a 10-year period.

During the first 10 years of the Mayo Lung Project, 68 roentgenographically inapparent ("occult") lung cancers were localized and apparently completely resected. A pathologic classification was developed based on depth of tumor infiltration. The five categories were (1) in situ carcinoma confined to surface epithelium or ducts of mucous glands or acini (23 cancers), (2) intramucosal invasion not greater than 0.1 cm from mucosal surface (12 cancers), (3) invasion to bronchial cartilages (11 cancers), (4) invasion to full thickness of bronchial wall (10 cancers), and (5) extrabronchial invasion (12 cancers). Multicentricity of lung cancer was studied in 54 patients, none of whom had a history of cancer of the respiratory tract, and all of whom had had "complete" surgical resection of the initial occult lung cancer (or cancers). Neoplasms that were initially multicentric occurred in 4 patients, and a subsequent primary lung cancer developed in 11. The rate of detection of second primary lesions was 42 per 1,000 person-years of observation. A high incidence of unresectable cancers and a low survival rate were noted among patients who had a subsequent primary tumor. These findings were primarily attributable to invasiveness of the subsequent primary cancer or to respiratory insufficiency that resulted from obstructive lung disease or previous pulmonary resection. Because of the high risk of development of a second primary cancer after initial surgical resection, it is important to treat the initial occult cancer as conservatively as possible consistent with "cure."

Aged↗
PubMed1984

Invasive Hürthle cell carcinoma of the thyroid: natural history and management.

Debate surrounds the natural history and appropriate management of Hürthle cell neoplasms of the thyroid. Some of the uncertainty stems from difficulty in the differentiation of benign from malignant lesions. We report the presentation, management, and outcome of patients with invasive Hürthle cell carcinoma who were examined at this institution between 1946 and 1971. We believe that our review allows us to make reasonable recommendations concerning the management of patients with this type of carcinoma.

Adult↗
PubMed1984

Laser-Doppler measurement of skin blood flow: comparison with plethysmography.

We compared laser-Doppler velocimetry with plethysmographically determined changes in skin blood flow (SkBF) in five studies on four men. Increments in SkBF were induced by raising whole-body skin temperature to 39 degrees C for 50-70 min. We found laser-Doppler blood flow (LDF) to correlate well with total forearm blood flow (FBF) within each study (r = 0.94-0.98), but the relationship varied among studies. Thus the slopes for the LDF vs. FBF relationship varied from 40 to 122 mV X ml-1 X 100 ml X min. The value for LDF at zero FBF, extrapolated from the regression relationships, ranged from 246 to 599 mV above the value for LDF set with the probe on a stationary object. The value for LDF when blood flow to the arm was mechanically occluded ranged from 110 to 230 mV. In a second series, we measured the LDF values from six sites on forearms of each of four normothermic men. There was marked regional variation, with 1.8- to 5.7-fold ranges in LDF within a given subject. Values for LDF during occlusion of the forearm were more consistent within and between subjects. Thus LDF appears to provide a good indicator of the response pattern of SkBF from the region of illuminated skin. However, variability in the relationship to total SkBF (probably arising from variation in the number of perfused capillaries in the small volume of tissue) and uncertainties in the value of LDF at zero SkBF make quantitative use difficult.

Adult↗
PubMed1984

Reflex regulation of sweat rate by skin temperature in exercising humans.

To find whether sweat rate (SR) and forearm skin blood flow ( SkBF ) were reflexly affected by skin temperature (Tsk) we used water-perfused suits to rapidly elevate Tsk during exercise. With this elevation in Tsk, there was a period of little net change in esophageal temperature (Tes) but marked responses in SR and SkBF . During this period a rise in Tsk of 4.2 +/- 0.3 degrees C was associated with an increase in SR of 0.44 +/- 0.09 mg X cm-2 X min-1 and an increase in SkBF of 3.27 +/- 0.42 ml X 100 ml-1 X min-1. Multiple linear regression analysis as well as comparison with control studies in which Tsk was kept cool also reveal a consistent role for Tsk in the reflex regulation of SR and SkBF . Responses in SR and FBF were much more marked at levels of Tsk below 33 degrees C. Below a Tsk of 33 degrees C, SR rose 0.30 +/- 0.06 mg X cm-2 X min-1 per degrees C rise in Tsk, whereas above 33 degrees SR rose only 0.05 +/- 0.01 mg X cm2 X min per degrees C. FBF rose 2.81 +/- 0.60 and 0.77 +/- 0.18 ml X 100 ml-1 X min-1 per degrees C rise in Tsk at the lower and upper ranges of Tsk, respectively.

Adult↗