The use of asymmetric-field inversion gel electrophoresis to predict tumor cell radiosensitivity

The success of a predictive assay for radiotherapy relies on the use of one or more tumor cell traits that equate with tumor radioresistance or radiosensitivity. These traits can be divided into intrinsic (genetic) and extrinsic (epi-genetic) factors. Most probably, a tumor's response to radiotherapy will be influenced by both of these sets of traits. Radiobiological analysis of cultured cells derived from explanted tumors of head and neck patients has shown that in vitro survival of tumor cells is not the only factor affecting tumor radiocurability. Two possible reasons are the high degree of selection involved in growing the cells in vitro and the inability to assess the contribution of the cell-cell contact effect with cultured cells. A possible means of overcoming both of these problems would be an assessment of the radiosensitivity of the cell population immediately after removal from the tumor. Since a good correlation exists between intrinsic cellular radioresistance and DNA double-strand break repair (DSBR) as assayed by the Neutral Elution technique [21], we have investigated the feasibility of using asymmetric field inversion gel electrophoresis (AFIGE) in identifying resistant tumor cells in vitro. AFIGE has several advantages over neutral elution in that it is faster (approximately 60-80 samples can be run on the same agarose gel) and, most importantly, one can visualize DNA damage and repair by staining the DNA with ethidium bromide.(ABSTRACT TRUNCATED AT 250 WORDS)

Nightmare prevalence in the healthy elderly

Fifty-one healthy elderly subjects (median age = 65) gave retrospective estimates of nightmare frequency in questionnaires and recorded the occurrence of nightmares in daily logs over a 2-week period. (a) Mean annual nightmare frequency as estimated from logs was only 65% as high among college student controls. (b) Elderly subjects were about 1/5 as likely as college students to report a problem with nightmares. (c) Frequency estimates on the basis of logs were over 10 times higher than retrospective estimates.

A genetic system for studying the activity of a proteolytic enzyme

We describe a genetic system for monitoring the activity of a specific proteolytic enzyme by taking advantage of the properties of the yeast transcriptional activator GAL4. The GAL4 protein contains two separable and functionally essential domains: the amino-terminal DNA binding domain and the carboxyl-terminal transcriptional activating domain. We constructed two hybrid proteins by inserting between the DNA binding domain and the activation domain of GAL4 either (i) a self-cleaving protease (3C protease of a picornavirus, coxsackievirus B3) or (ii) a mutant form of the protease that is unable to cleave. We show that, although the hybrid protein containing the mutant protease activates transcription of GAL1-lacZ reporter gene, the hybrid protein bearing the wild-type protease is proteolytically cleaved and fails to activate transcription. Our approach to monitor the proteolytic activity could be used to develop simple genetic systems to study other proteases.

Hypernatremic dehydration complicated by peripheral gangrene in elderly--case reports

The authors describe the association of hypernatremic dehydration and peripheral gangrene in elderly patients. This association is known in infancy but hitherto has not been described in the elderly.

Daily mortality and PM10 pollution in Utah Valley

The association between daily mortality and respirable particulate pollution (PM10) in Utah County was assessed from April 1985 through December 1989. Poisson regression analysis was used to regress daily death counts on PM10 pollution levels, controlling for variability in the weather. A significant positive association between nonaccidental mortality and PM10 pollution was observed. The strongest association was with 5-d moving average PM10 levels, including the concurrent day and the preceding 4 d. An increase in 5-d moving average PM10 levels, equal to 100 micrograms/m3, was associated with an estimated increase in deaths per day equal to 16%. The association with mortality and PM10 was largest for respiratory disease deaths, next largest for cardiovascular deaths, and smallest for all other deaths. Mean PM10 concentrations during the study period equaled 47 micrograms/m3. The maximum 24-h and 5-d moving average PM10 levels equaled 365 and 297 micrograms/m3, respectively. Relatively low levels of sulfur dioxide, aerosol acidity, and ozone suggested an independent association between mortality and PM10. The relative risk of death increased monotonically with PM10, and the relationship was observed at PM10 levels that were well below the current National Ambient Air Quality Standard of 150 micrograms/m3.

Profuse diaphoresis as the presenting symptom of myocardial ischemia with normal appearance of coronary arteriogram--a case report

The authors present a case of a patient suffering from profuse diaphoresis as the sole manifestation of myocardial ischemia (syndrome x or coronary vasospasm). The diagnosis was established by positive exercise thallium 201 imaging and normal-appearing coronary arteriogram.

Growth hormone induces c-fos and c-jun expression in cells with varying requirements for differentiation

GH is one of the major factors required for the differentiation of 3T3-F442A preadipocyte fibroblasts into adipocytes. An early event following the addition of GH to 3T3-F442A preadipocytes is induction of the expression of c-fos and c-jun. Although c-fos and c-jun expression has been observed in conjunction with growth factor-stimulated differentiation in several cell types, it is not clear whether protooncogene expression and differentiation are necessarily related. In this study the relationship between the induction of these protooncogenes and differentiation was evaluated by taking advantage of several cell lines that are related to 3T3-F442A cells but have varying GH requirements for differentiation. Adipose differentiation in the adipogenic cell lines 3T3-L1 and 3T3-GI-16 is known to be GH independent, requiring insulin or insulin-like growth factor-I. In both 3T3-L1 and 3T3-GI-16 preadipocytes, GH, nevertheless, induced the expression of mRNA for both protooncogenes. GH (2.2 nM) was more effective than insulin (1 microM) in inducing c-fos expression in these two adipogenic cell lines, suggesting that induction of the protooncogenes is not sufficient to induce adipogenesis. 3T3-C2 fibroblasts do not differentiate in response to any of the stimuli that convert 3T3-F442A fibroblasts to adipocytes. However, GH (2.2 nM) as well as calf serum induced the expression of c-fos and c-jun in 3T3-C2 cells. NIH-3T3 fibroblasts, which do not undergo differentiation, also showed induction of c-fos by GH. Thus, GH-induced expression of c-fos and c-jun occurs in nondifferentiating cells. Furthermore, in differentiated 3T3-F442A adipocytes, GH stimulated the expression of c-fos and c-jun as it does in the preadipocytes. Since GH elicits a variety of metabolic responses in 3T3-F442A adipocytes, the present findings raise the possibility that induction of c-fos and c-jun expression might be associated with multiple events in GH-stimulated 3T3-F442A adipocytes. The lack of requirement for GH in GH-independent and nondifferentiating cells compared to 3T3-F442A cells does not appear to reflect the lack of GH receptors, since expression of mRNA for the GH receptor was evident in all of the cell types tested and, thus, corresponds with the ability of GH to induce protooncogene expression. Although GH-induced c-fos expression was relatively invariant, since it was evident in all of the cell types studied, this response could clearly be regulated, since it was attenuated by prior exposure to GH or serum in 3T3-F442A preadipocytes.(ABSTRACT TRUNCATED AT 400 WORDS)

The selective cytotoxic effect of carotenoids and alpha-tocopherol on human cancer cell lines in vitro

This study compares the toxic effects of the carotenoids, beta-carotene and canthaxanthin, and alpha-tocopherol (vitamin E) on human tumor cells and their normal counterparts in vitro. Seven different malignant cell lines were examined: oral carcinoma (two cell lines), breast (two cell lines), lung carcinoma (two cell lines), and malignant melanoma. The in vitro cell culture assays showed a consistent morphologic change in the affected tumor cells following treatment with carotenoid or vitamin E. A rounding of the tumor cells and eventual lifting off the tissue culture plate were observed. These changes were apparent after 1 to 5 hours of treatment depending on the tumor cell line. Associated with these observable cellular changes were quantitative reductions in proliferation (3H-thymidine proliferation) and succinic dehydrogenase activity (MTT assay). In addition, there was a noticeable change in protein expression, with an increased expression of a 70-kD protein following treatment with beta-carotene. This protein was associated with tumor cells showing a decrease in proliferation (oral carcinoma, malignant melanoma) but not with normal keratinocytes or melanocytes. These studies substantiate a selective cytotoxic effect on human tumor cell growth by carotenoids and alpha-tocopherol in vitro, and may provide an explanation of the therapeutic activity of these agents and their possible use in the treatment of premalignancy or early oral carcinoma.

Methylphenidate in Aggressive Hyperactive Boys: II. Indirect Effects of Medication Treatment on Peer Behavior

ABSTRACT The present study examines the indirect "spillover" effects of methylphenidate on the behavior of the classmates of drug-treated children in public school settings, and it measures the extent to which medication normalizes hyperactive and noncompliant-aggressive behaviors. Eleven aggressive hyperactive boys, who met DSM-III diagnostic criteria for attention deficit disorder, received placebo and methylphenidate in a double-blind crossover design. Medication effects were assessed by conducting observations of the drug-treated boy and his peers in the classroom and lunchroom settings. In most classrooms, a spillover effect did not occur for most of the behaviors assessed, but there was a decrease in the rate of nonphysical aggression exhibited by peers as a function of the hyperactive child's methylphenidate dose. Peers were generally less aggressive when the hyperactive boys were receiving methylphenidate than when they received placebo. In the lunchroom, in contrast, peers appeared slightly more noncompliant and aggressive when the aggressive hyperactive boys were receiving medication compared with placebo, but these differences did not attain statistical significance. Methylphenidate effectively normalized the negativistic behaviors of the aggressive hyperactive boys in the classroom. In some cases, the frequency of occurrence of certain behaviors dropped significantly below the level of the hyperactive child's peers. This "supranormalization" may reflect behavioral toxicity of the psychostimulant.

Cessation of recurrent bleeding from gastrointestinal angiodysplasia, after beta blocker treatment in a patient with hypertrophic subaortic stenosis--a case history

The authors present the case of an elderly patient suffering from obstructive cardiomyopathy and bleeding colonic angiodysplasia. After treatment with propranolol, the bleeding stopped without recurrence.

Air pollution and the duration of acute respiratory symptoms

The possibility that air pollution exposure can extend the duration of respiratory symptoms was examined in a diary study of student nurses. This diary study has already shown associations between air pollution and incidence rates of respiratory symptoms. After individual risk factors and temperature were controlled for, photochemical oxidants were significantly (p less than .0001) associated with the duration of episodes of coughing, phlegm, and sore throat. Some heterogeneity of response to oxidants was seen; there was little effect on asthmatics, but the impact increased as family income increased. Plots of the mean duration of symptoms, by quintiles of oxidants, for which the other covariates were controlled, showed strong signs of a dose-response relationship for coughing and phlegm and moderate signs of a monotonic dose-response relationship for sore throat. The relationships continued for concentrations below the current ambient standard for ozone. Chest tightness or discomfort was significantly associated with sulfur dioxide (p = .016), but the effect seemed mainly restricted to asthmatics. However, evidence for a dose-dependent increase was weak.

Increased mortality in Philadelphia associated with daily air pollution concentrations

Cause-specific deaths by day for the years 1973 to 1980 in Philadelphia, Pennsylvania, were extracted from National Center for Health Statistics mortality tapes. Death from accidents (International Classification of Disease, Revision 9 greater than or equal to 800) and deaths outside of the city were excluded. Daily counts of deaths were regressed using Poisson regression on total suspended particulate (TSP) and/or SO2 on the same day and on the preceding day, controlling for year, season, temperature, and humidity. A significant positive association was found between total mortality (mean of 48 deaths/day) and both TSP (second highest daily mean, 222 micrograms/m3) and SO2 (second highest daily mean, 299 micrograms/m3). The strongest associations were found with the mean pollution of the current and the preceding days. Total mortality was estimated to increase by 7% (95% CI, 4 to 10%) with each 100-micrograms/m3 increase in TSP, and 5% (95% CI, 3 to 7%) with each 100-micrograms/m3 increase in SO2. When both pollutants were considered simultaneously, the SO2 association was no longer significant. Mortality increased monotonically with TSP. The effect of 100 micrograms/m3 TSP was stronger in subjects older than 65 yr of age (10% increase) compared with those younger than 65 yr of age (3% increase). Cause-specific mortality was also associated with a 100-micrograms/m3 increase in TSP: chronic obstructive pulmonary disease (ICD9 490-496), +19% (95% CI, 0 to 42%), pneumonia (ICD9 480-486 & 507), +11% (95% CI, -3 to +27%), and cardiovascular disease (ICD9 390-448), +10% (95% CI, 6 to 14%). These results are somewhat higher than previously reported associations, and they add to the body of evidence showing that particulate pollution is associated with increased daily mortality at current levels in the United States.

Nightmare prevalence in the healthy elderly

Fifty-one healthy elderly subjects (median age = 65) gave retrospective estimates of nightmare frequency in questionnaires and recorded the occurrence of nightmares in daily logs over a 2-week period. (a) Mean annual nightmare frequency as estimated from logs was only 65% as high among college student controls. (b) Elderly subjects were about 1/5 as likely as college students to report a problem with nightmares. (c) Frequency estimates on the basis of logs were over 10 times higher than retrospective estimates.

The impact of anticipation of job loss on psychological distress and worksite blood pressure

The impact of occupational stressful life events on psychological distress and blood pressure was examined among employees of a major New York City brokerage firm undergoing massive layoffs. One hundred thirty-nine employees of the firm, who had participated in a blood pressure screening in 1986, were rescreened during the period of layoffs within their company in 1989. About two-thirds of the 139 employees reported being "somewhat" or "very" anxious or upset in 1989 during the period of layoffs, and psychological distress was significantly elevated among those employees reporting possible or definite layoff or job change and/or difficulty in obtaining a comparable job. However, we found no increase in overall blood pressure level, and no effect of anticipation of job loss on 1989 blood pressure when controlling for 1986 blood pressure level, age, body mass index, work hours, and other demographic variables. On the other hand, employment in a department sold to another employer on the day of screening, as well as employment in a clerical job title, were both associated with significant increases in diastolic blood pressure of about 5 mm Hg.

Air pollution and respiratory symptoms in preschool children

A diary study on a random sample of 625 Swiss children aged 0 to 5 yr was conducted in two cities in Switzerland to investigate the association between air pollution and respiratory symptoms. Total suspended particulates (TSP), SO2 and NO2 were measured by city monitor. In addition, passive samplers inside and outside the home measured NO2 concentration during the 6 wk each child was on the diary. Diaries were filled out by parents, and 20% were validated with the attending pediatrician's case notes. Incidence and duration of symptom episodes were examined separately. The study included any episode, episodes of coughing without runny nose, upper respiratory episodes, and episodes of breathing difficulty. In regressions using 6-wk average pollution that controlled for medical history, NO2 measured outdoors but not indoors was associated with the duration of any symptom. Total suspended particulates were a more significant predictor of duration of any symptom than NO2. The 6-wk average TSP was significantly associated with incidence of coughing episodes and marginally significant as a predictor of upper respiratory episodes. Previous day's TSP was a significant predictor of incidence of upper respiratory symptoms. Annual average of NO2 was associated with the duration of any episode and of upper respiratory episodes. We conclude that the incidence and duration of respiratory symptom episodes are likely associated with particulate concentrations and duration may be associated with NO2.

Particulate air pollution and daily mortality in Steubenville, Ohio

Particulate air pollution has been associated with daily mortality in London, England, both in the smog episodes of the 1950s and at the lower pollution levels of the late 1960s and early 1970s. Replicating these findings in the United States has been difficult, because particulates are usually sampled every sixth day. Replication, particularly with a gravimetric measure of particulates, is important in assessing the causality of the relation. Daily measurements of total suspended particulates by high volume gravimetric sampler are available for the Steubenville, Ohio, metropolitan area. These were matched to daily mortality counts from the detail mortality tapes of the National Center for Health Statistics. Deaths of residents which occurred outside the Steubenville Standard Metropolitan Statistical Area were excluded. Because of the much smaller population, the average total number of deaths per day in the Steubenville Standard Metropolitan Statistical Area over the 11-year period 1974-1984 was about 1% of the deaths in a typical London winter. Despite this reduced statistical power, total suspended particulate count was significantly associated with increased daily mortality in Poisson regression analyses controlling for season and temperature. An increase in particulates of 100 micrograms/m3 was associated with a 4% increase in mortality on the succeeding day. Associations with sulfur dioxide were not significant after adjustment for particulates. The relation appeared to continue at levels well below the current National Ambient Air Quality Standard.

Host and environmental factors influencing the peripheral blood leukocyte count

The peripheral leukocyte count is an important predictor of mortality. Hence, host and environmental factors influencing the peripheral leukocyte count are of interest. The authors studied 8,635 subjects, aged 30-74 years, who were seen as part of the National Health and Nutrition Examination Survey II in 1976-1980, and sought to assess the relation of age, sex, obesity (body mass index), alcohol use, and various parameters of cigarette smoking to the peripheral leukocyte count using multiple regression analysis. Various parameters of cigarette smoking were statistically significant independent predictors of the peripheral leukocyte count with higher leukocyte counts seen among current smokers, relative to former or never smokers. Among current smokers, a dose-response relation was seen for cigarettes/day and total pack-years smoked. A dose-response relation with pack-years and years since quitting was seen in former smokers. Other variables that were statistically significant independent predictors of a higher peripheral blood leukocyte count were younger age, male sex, increased body mass index, and decreased alcohol consumption. Although the specific cell or cells responsible for these relations are not defined by this analysis, the results support the suggestion that a number of host and environmental factors can influence cellular markers of inflammation.