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Biomedical subjects

H Evans

Publications and source records attributed to H Evans.

At least 19 recordsLinked to original sources
PubMed1990

Treatment of patients with isolated axillary nodal metastases from an occult primary carcinoma consistent with breast origin.

The records of 42 patients who had axillary metastases compatible with a clinically occult breast primary were reviewed. Forty patients had mammography performed as part of their evaluations. Mastectomy yielded the primary tumor in one of 13 patients; biopsy yielded positive results in one of five. Among the 29 patients who did not undergo mastectomy, 16 received breast irradiation, and 13 were simply observed for signs of the primary tumor. For the patients who did not undergo mastectomy, the 5-year actuarial risk for appearance of a primary was 17% in the irradiated group versus 57% in the nonirradiated group (P = 0.06). Patterns of failure are correlated with stage and local and systemic therapy. The results affirm our belief that patients with axillary metastases histologically consistent with breast tumor should be treated identically to patients with similar nodal stages and proven breast primaries.

Adult↗
PubMed1990

Clear cell carcinoma of the sigmoid mesocolon: a tumor of the secondary müllerian system.

Clear cell carcinoma was found in the sigmoid mesocolon of a 54-year-old woman, 6 years after the removal of all ovarian tissue. This tumor is of müllerian origin. In addition to the müllerian structures proper--the fallopian tubes, uterus, cervix, and upper vagina--a "secondary müllerian system" is present diffusely throughout the pelvis and lower abdomen. This case represents a tumor of the secondary müllerian system.

Adenocarcinoma↗
PubMed1990

Desmoid tumors: a 20-year radiotherapy experience.

From 1964 through 1984, 45 patients were referred for radiation therapy for desmoid tumor. Fourteen patients had inoperable lesions, or gross residual disease after incomplete resection. Thirty-one patients received postoperative XRT for positive margins or concern about the adequacy of the margin. The minimum follow-up was 2 years, maximum 22 years, median 7.6 years. No patient was lost to follow-up. The primary site was head and neck in 5, upper extremity in 10, chest wall and back in 8, abdomen 2, pelvis 4, and lower extremity 16. All patients were treated with megavoltage radiation therapy using shrinking field techniques. Large fields received a median dose of 50 Gy in 25 fractions. Boost fields were used in the majority of patients to deliver an additional dose of 7 to 27 Gy. The range of total doses was 50 to 76.2 Gy. Three patients received a boost with neutrons. Analysis of patients with inoperable or gross residual showed tumor control in 10 of 14 with a median follow-up of 9.4 years. Resolution of gross disease occurred at a range of 1/2 to 64.3 months with a median of 9 months. There was no evidence of a higher probability of ultimate control at higher doses. Tumor control was equal for men and women. The ten patients with local control had doses from 50 to 76.2 Gy whereas the four patients with in field failures had tumor doses of 57 to 66.4 Gy. There was no difference in median dose for patients with local control (60.3 Gy) versus those with tumor recurrence (60 Gy). For subclinical disease, 31 patients receiving postoperative or preoperative XRT had a 77 percent probability of local control in spite of the history of multiple tumor recurrences; local control was achieved in 8 of 9 with negative or uncertain margins and 16 of 22 with positive margins. An analysis of local control as a function of the number of operations revealed that patients referred for adjuvant radiotherapy with no more than two operative procedures had an 88 percent probability of local control, versus 66 percent for more than two operative procedures. All grade 3 complications (defined as requiring surgical intervention or prolonged hospitalization) occurred with doses above 60 Gy. Management of recurrences was successful in 8 of the 11 patients and no patient has died of tumor.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1990

Occurrence of 222Rn and progeny in natural gas processing plants in western Canada.

In Western Canada, there are many plants that process natural gas to remove impurities (CO2, H2S, H2O) and recover natural gas liquids (propane, butane, etc.). Trace quantities of 222Rn present in the inlet stream are concentrated in streams rich with propane. Potential hazards to plant operators include direct inhalation of 222Rn and progeny; exposure to gamma radiation from short-lived progeny deposited inside equipment; or inhalation of 210Pb when contaminated equipment is opened for repair. Twenty-four plants operated by seven companies cooperated to assess these potential hazards. The findings indicate a substantial flux of 222Rn and progeny passing through the plants, but little accumulation of radionuclides. In no case was there evidence of significant exposure of plant operators or maintenance personnel to ionizing radiation. Further investigation of pipeline operations, and chemical operations using natural gas liquids as feed stock, is recommended.

Bismuth↗
PubMed1990

Energy absorption, lean body mass, and total body fat changes during 5 weeks of continuous bed rest.

Inactivity causes profound changes. We determined the nature of the body composition changes due to inactivity, and sought to determine if these changes are secondary to changes in energy absorption. Volunteers were 15 healthy males who lived on a metabolic research ward under close staff supervision for 11 weeks. Subjects were ambulatory during the first 6 weeks and remained in continuous bed rest for the last 5 weeks of the study. Six male volunteers (age 24-61 years, height 175.7 +/- 4.2 cm) were selected for body composition measurements. Nine different male volunteers (age 21-50 years, height 177.7 +/- 5.0 cm) were selected for energy absorption measurements. The volunteers were fed weighed conventional foods on a constant 7-d rotation menu. The average daily caloric content was 2,592 kcal. Comparing the 5 weeks of continuous bed rest with the previous 6 weeks of ambulation we observed: no change in energy absorption or total body weight during bed rest, but a significant decrease in lean body mass and a significant increase in total body fat (p less than 0.05).

Adipose Tissue↗
PubMed1989

Expression of Epstein-Barr virus transformation-associated genes in tissues of patients with EBV lymphoproliferative disease.

Epstein-Barr virus (EBV) has been associated with serious or fatal lymphoproliferative disease in immunocompromised patients. EBV nuclear protein 2 and latent membrane protein are characteristically expressed in B lymphocytes proliferating in vitro in response to growth transformation by EBV. These two proteins are thought to be effectors of lymphocyte growth since they increase the expression of B-lymphocyte activation (CD23) and cell-adhesion (LFA 3 and ICAM 1) molecules in vitro. Using monoclonal antibody-immune microscopy, we have demonstrated that these two EBV proteins and their associated B-lymphocyte activation or adhesion molecules are expressed in the infiltrating B lymphocytes in immunocompromised patients with EBV lymphoproliferative disease. These monoclonal antibodies should be useful in the early diagnosis of EBV lymphoproliferative disease and in distinguishing it from other B-lymphocyte cancers associated with EBV, such as Burkitt's lymphoma. The finding of EBV nuclear protein 2 and latent membrane protein and their associated activation or adhesion molecules provides a further pathophysiologic link between EBV and the proliferation of B lymphocytes in immunocompromised patients.

Adult↗
PubMed1989

Severely heated therapeutic factor VIII concentrate of high specific activity.

A new method for the manufacture of a heated factor VIII concentrate of high specific activity (2-6 IU factor VIII:C/mg protein) has been developed. Addition of heparin to cryoprecipitate extract at acid pH precipitated fibrinogen and fibronectin. Factor VIII was then recovered from the supernatant by precipitation with glycine and sodium chloride. After re-solution and desalting on Sephadex G-25, the concentrate was sterile-filtered and lyophilised. The dried product was stable to heating in the final container at 80 degrees C for 72 h. Data from 25 consecutive batches of concentrate prepared from 1,200-1,500 kg plasma pools are presented. The mean final yield of heated product was 190 IU factor VIII:C/kg plasma. The concentrate has been found to be safe and effective in clinical use.

Chemical Precipitation↗
PubMed1988

Hepatocellular carcinoma: importance of histologic classification as a prognostic factor.

The characteristics and clinical courses of 15 patients with fibrolamellar carcinoma have been compared to 62 patients with hepatocellular carcinoma treated over the same time period. Marked differences were found in patient, tumor, and treatment characteristics. Survival rates in these two groups of patients have been compared by univariate analysis of the subsets of those patient, tumor, and treatment characteristics. The longer survival of the group of patients with fibrolamellar carcinoma could not be accounted for by the prevalence or absence of any of these characteristics. Comparison of subsets of patients with documented noncirrhotic livers or those having complete resection of their tumors revealed a significantly prolonged survival in patients with the fibrolamellar variant. The 5 year survival rate of the patients with fibrolamellar carcinoma who had complete tumor resection was 45 percent, with a median survival time of 50 months. The 5 year survival of patients with hepatocellular carcinoma who had complete tumor resection was 0 percent, with a median survival time of 22 months.

Adolescent↗
PubMed1987

Changes in nuclear magnetic resonance (T2) relaxation of limb tissue with bed rest.

Bed rest is used to simulate the effects of weightlessness on human physiology. A spin-echo procedure was used to image the lower leg of 15 normal male volunteers before and after 5 weeks of horizontal bedrest. In addition to noninvasively measuring muscle size changes, accurate T2 images were produced to investigate possible relaxation time changes immediately (2-4 h) and 1-2 days after bed rest. Subcutaneous fat showed no change in T2, bone marrow showed a decrease, and muscle showed no change immediately after bed rest but increased 1-2 days following reambulation.

Adipose Tissue↗
PubMed1987

Spinal bone mineral after 5 weeks of bed rest.

Patients put at bedrest for medical reasons lose 1-2% of spinal bone mineral per week. Losses of this magnitude during even short-term space flights of a few months would pose a serious limitation and require countermeasures. The spinal bone mineral (L2-L4) was determined in 6 healthy males (precision = 2%) before and after 5 weeks of complete bed rest. Only one individual had a significant loss (3%) and the -0.9% mean change for the 6, was not significant (P = 0.06). The average negative calcium balance during the 5 weeks was 4 g or 0.36% of total body calcium, similar to that reported in other bed-rest studies. Spinal bone loss, however, in healthy bed-rested males is significantly less than reported for bed-rested patients, suggesting that a large loss of spinal bone mineral does not occur during space flight missions lasting 5 weeks or less.

Adult↗
PubMed1986

Serial trypsin inhibitory capacity and ceruloplasmin levels in prematures at risk for bronchopulmonary dysplasia.

Oxidant injury and release of proteolytic enzymes in prematures with respiratory distress syndrome (RDS), who are treated with ventilators and oxygen, have been postulated as possible causes of bronchopulmonary dysplasia (BPD). The premature may be at particular risk due to low levels of antiproteases, such as alpha-1-proteinase inhibitor (alpha 1PI), and antioxidants, such as ceruloplasmin (CER). Both alpha 1PI and CER deficiencies have been correlated with the severity of RDS. We studied serial alpha 1PI activity as measured by trypsin inhibitory capacity (TIC) and CER in the serum 27 prematures who required ventilator therapy for RDS. Serum TIC values for day 1 were significantly lower (0.34 vs. 0.92 mg inhibited/ml of sample) in the 13 patients who developed BPD compared to the 14 who did not. No significant differences were seen on succeeding days. No significant differences in CER were seen, although both groups had levels 33-50% of adult normals (11.3 vs 9.3 mg/dl). Other significant variables included birthweight (p less than 0.005), severity of RDS (p less than 0.03), and gestational age (p less than 0.03). One way analysis of variances demonstrated day 1 TIC to be the most significant variable (p less than 0.0001), followed by weight (p less than 0.007), severity RDS (p less than 0.04), and gestational age (p less than 0.03). CER levels were not a significant variable. A formula utilizing unstandardized canonical discriminant function including day 1 TIC, birthweight, severity of RDS, and gestational age was 100% sensitive and 85% specific in the prediction of BPD for the original study group. In an additional 25 consecutive admissions with severe RDS of whom 18 survived, the formula was 100% sensitive (6/6) and 75% specific (9/12).(ABSTRACT TRUNCATED AT 250 WORDS)

Birth Weight↗
PubMed1985

A rapid luminescently monitored enzyme immunoassay for IgE.

A novel halophenol-enhanced luminol-peroxide luminescent detection method for horseradish peroxidase has been tested in an enzyme immunoassay for IgE. The luminescent enzyme immunoassay was reproducible (within-batch CV, 3.9-13.2%) and values obtained on serum samples showed good agreement with those obtained by colorimetric enzyme immunoassay. The major advantages of the luminescent detection method are that it is rapid, 30 s compared with 30 min for the colorimetric assay using o-phenylenediamine, and the luminescent signal is intense and stable for several minutes.

Colorimetry↗
PubMed1985

Bone and muscle atrophy with suspension of the rat.

A modification of the Morey tail suspension model was used to determine atrophic responses of rat bone and muscle with 14-90 days unloading of the hindlimbs. Bone uptake of methylene diphosphonate followed a phasic pattern similar to changes in bone formation rate in immobilized dogs and rats. Increased uptake at 60 days (P = 0.01, femur) indicated an increased bone metabolism. Regional densitometry demonstrated a preferential loss of bone mineral in the trabecular mass (P = 0.02) at 30 days and in the cortical shaft by 90 days (P = 0.03). Maximal muscle atrophy occurred within 14-30 days. The gastrocnemius was less severely affected by suspension than by immobilization techniques, whereas the soleus atrophied (by weight) similarly, suggesting that muscle atrophy in the suspension model is distinctly different from immobilization atrophy. One significant response of skeletal muscle to suspension was an altered blood distribution. Muscle blood distribution changes reflect the hypodynamic state of muscle that continues to contract but probably at an altered rate in response to altered functional demands.

Animals↗