Expression of the glutamine metabolism-related proteins glutaminase 1 and glutamate dehydrogenase in canine mammary tumours.

Glutamine metabolism is an important metabolic pathway for cancer cell survival, and there is a critical connection between tumour growth and glutamine metabolism. Because of their similarities, canine mammary carcinomas are useful for studying human breast cancer. Accordingly, we investigated the correlations between the expression of glutamine metabolism-related proteins and the pathological features of canine mammary tumours. We performed immunohistochemical and western blot analysis of 39 mammary tumour tissues. In immunohistochemical analysis, the expression of glutaminase 1 (GLS1) in the epithelial region increased according to the histological grade (P < .005). In the stromal region, complex-type tumours displayed significantly higher GLS1 intensity than simple-type tumours. However, glutamate dehydrogenase expression did not show the same tendencies as GLS1. The western blot results were consistent with the immunohistochemical findings. These results suggest that the expression of GLS1 is correlates with clinicopathological factors in canine mammary tumours and shows a similar pattern to human breast cancer.

Electroporation markedly improves Sleeping Beauty transposon-induced tumorigenesis in mice.

The Sleeping Beauty (SB) transposon system is an important tool for genetic studies. It is used to insert a gene of interest into the host chromosome, thus enabling permanent gene expression. However, this system is less useful in higher eukaryotes because the transposition frequency is low. Efforts to improve the efficacy of the SB transposon system have focused on the method of gene delivery, but although electroporation has recently attracted much attention as an in vivo gene delivery tool, the simultaneous use of electroporation and the SB transposon system has not been studied for gene transfer in mice. In this study, electroporation was used in a model of SB transposon-induced insertional tumorigenesis. Electroporation increased the rate of tumor development to three times that of the control group. There was no difference in phenotype between tumors induced with the SB transposon system alone and those induced by the SB transposon and electroporation. Electroporation therefore may be an efficient means of improving the efficacy of gene transfer via the SB transposon system.

Relationship of intraabdominal fat as measured by magnetic resonance imaging to postprandial lipemia in middle-aged subjects.

Adipose distribution has been associated with coronary artery disease and its risk factors. We previously described an association between postprandial triglyceride response (pptg response) to a standard high-fat meal and extracranial carotid atherosclerosis. This study was designed to evaluate the association between intraabdominal fat and pptg response. Twenty-nine subjects were recalled for determination of intraabdominal fat by magnetic resonance imaging (MRI). Fat was quantified according to an inversion recovery protocol previously validated and the cross-sectional area of intraabdominal fat at the umbilicus was analyzed as an independent variable. We observed a strong independent correlation between intraabdominal fat and pptg response to a fatty meal (r = 0.521, P < 0.05). Baseline triglyceride was also independently correlated with postprandial triglycerides (r = 0.631, P < 0.05). In univariate analysis, intraabdominal fat was correlated with age, sex, body mass index (BMI), waist-to-hip ratio (WHR), and dietary saturated fatty acids. The association with age and BMI persisted in multivariate analyses.

A prospective reevaluation of transient ischemic attacks as a risk factor for death and fatal or nonfatal cardiovascular events.

BACKGROUND AND PURPOSE: Transient ischemic attack (TIA) is generally considered a risk factor for death and cardiovascular events. This assumption is based on comparisons of the survival of the TIA population with that of the general population. Such comparisons may provide biased estimates of the risk associated with TIA because the general population is usually more healthy than TIA patients. METHODS: Using a prospective case-control study design, we report the comparison of a TIA population (n = 280) and a control group (n = 399) with a comparable cardiovascular risk factor burden. Proportional hazards analysis was used to compare survival time and time to fatal or nonfatal stroke and/or myocardial infarction for the two study groups. Comparisons were made without adjustment for risk factors and after adjustment for age, race, sex, and major cardiovascular risk factors. RESULTS: Before adjustment for age-race-sex or risk factors, TIA proved to be a risk factor for early mortality, stroke, and myocardial infarction (P < .05). Adjustment for age-race-sex disparities between the case and control groups explained much of the differences in mortality, as the hazard ratio was reduced from 2.2 to 1.4. However, adjustment for age-race-sex or age-race-sex and risk factors did not markedly reduce the role of TIA as a risk factor for stroke or myocardial infarction. CONCLUSIONS: Although TIA proved to be a risk factor for stroke or myocardial infarction, it apparently plays a smaller role in the risk of death.

Postprandial triglyceridemia and carotid atherosclerosis in middle-aged subjects.

BACKGROUND AND PURPOSE: It has been suggested that a postprandial accumulation of triglyceride-rich lipoproteins promotes the development of atherosclerosis. This study was designed to test the hypothesis that postprandial lipemia is independently associated with intima-media thickening of the extracranial carotid arteries. METHODS: Forty-seven middle-aged, moderately hypercholesterolemic individuals were recruited for a 1-day study of the lipemic response to a standard high-fat test meal. The formula was fed at a dose of 65 g fat/m2 body surface area, after a 14-hour fast, and blood was obtained for triglyceride analysis hourly for 8 hours. A baseline lipid profile was obtained. Each subject underwent a carotid ultrasound examination. The extent of alimentary lipemia (peak triglyceride response) was correlated with the carotid artery wall thickness as measured by B-mode ultrasound. RESULTS: Univariate analyses indicated an inverse correlation between peak triglyceride response and high density lipoprotein cholesterol concentration and a direct correlation with male sex, baseline triglyceride concentration, background fat intake, and waist-to-hip ratio. Of these, the only variable that showed a univariate correlation with B-mode score was peak triglyceride response. Age and cigarette smoking were also correlated with B-mode score in univariate analyses. The correlation coefficient (r = 0.52) between peak triglyceride response to a fat-rich meal and B-mode score was significant (p less than 0.002) and remained so in multivariate analysis. Forward-selection stepwise regression resulted in the inclusion of only peak triglyceride response (p = 0.001) and smoking history (p = 0.005) as important predictors of carotid wall thickness in a linear model. CONCLUSIONS: The association between lipemic response and carotid wall thickness suggests that prolonged exposure of arterial wall cells to triglyceride-rich chylomicron remnants enhances the atherogenic process.

Reevaluation of transient ischemic attacks as a risk factor for early mortality.

The prevailing belief that transient ischemic attack is a risk factor for cardiovascular morbidity and mortality is based primarily on comparisons of survival of patients after transient ischemic attacks to that of an age-, race-, and sex-adjusted general population. Concomitant conditions that carry a high risk of premature mortality or morbidity, such as ischemic heart disease, hypertension, and diabetes, are very prevalent among patients with transient ischemic attacks. Hence, the poor prognosis of such patients may be attributable to these factors rather than their transient ischemic attack per se, which may only serve to bring patients into the medical system. We compared the survival of 336 patients after transient ischemic attack to that of a control group with a similar risk factor profile consisting of 6,710 patients evaluated for cardiac catheterization. Survival estimates, both unadjusted and adjusted for risk factors, did not differ between the two groups. Three-year survival estimates, after adjustment to the mean value of covariates, were 94% for the patients with transient ischemic attacks and 91% for the controls. These results suggest that the transient ischemic attack may not be an independent risk factor for mortality, although it may identify patients already at increased risk from coexisting conditions.

Central adipose distribution is related to coronary atherosclerosis.

A "male" distribution of adipose tissue in women (excess of fat in the abdomen compared with that in the hips; i.e., elevated waist/hip ratio) has been related to symptomatic cardiovascular disease. An elevated waist/hip ratio has also been related to symptomatic cardiovascular and cerebrovascular diseases in men, as well as to risk factors for these diseases and various metabolic conditions. To determine whether adipose distribution was related to coronary atherosclerosis, we performed a case-control study in patients with angiographically documented coronary atherosclerosis (cases) and in angiographically normal hospital and neighborhood controls. The data show that distribution of adiposity as assessed by waist/hip ratio is significantly related to coronary atherosclerosis in both females and males. Waist/hip ratio is significantly greater in female cases compared with either control group; in males, waist/hip ratio is significantly greater in cases compared with asymptomatic neighborhood controls but not compared with patients with normal coronary arteries. These results persist after control for age, plasma concentrations of lipids and lipoproteins, body mass index, history of hypertension, history of diabetes, and smoking status. The connection between the male adipose distribution in females and coronary atherosclerosis partly explains the greater likelihood of symptomatic cardiovascular disease in them. Males with excess deposition of fat in the abdominal region are also likely to experience increased risk.

Comparison of hospital and neighborhood controls in a study of coronary artery disease.

Case-control studies of risk factors for coronary artery disease (CAD) have almost invariably employed hospital controls, with minimal or no coronary artery stenosis. Although there is an important advantage in knowing the CAD status of controls, such groups are subject to bias related to hospitalization. To evaluate the generalizability of results obtained from studies using hospital controls, we compared risk factors in 342 hospital controls free of angiographic evidence for CAD, 168 neighborhood controls without symptoms of CAD, and 450 CAD patients. Coronary artery disease in cases and hospital controls was established arteriographically. No significant differences were found between the male control groups for total and low density lipoprotein (LDL) cholesterol, LDL apo-B, pack-years of smoking, body mass index, proportion with hypertension, diabetes and family history of coronary heart disease. Compared with neighborhood controls, male hospital controls had significantly lower high density lipoprotein (HDL) cholesterol, higher triglycerides and uric acid and scored higher on the Framingham Type A behavior pattern scale. Among women, the hospital control group had significantly lower LDL cholesterol and fewer pack-years of smoking, and a greater prevalence of hypertension than the neighborhood group. A greater proportion of both male and female hospital controls had left ventricular hypertrophy, and there were more current smokers among the neighborhood controls in both sexes. Age adjustment did not change these comparisons. While very few neighborhood controls were treated with beta-blockers, 32.7% of male and 41.4% of female hospital controls were so medicated. Control for beta-blocker use eliminated the difference in HDL cholesterol and triglycerides between the two male control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the associations between carotid artery atherosclerosis and coronary artery stenosis. A case-control study.

To evaluate the consistency, strength, and independence of the relation of carotid atherosclerosis to coronary atherosclerosis, we quantified coronary artery disease risk factors and extent of carotid atherosclerosis (B-mode score) in 343 coronary artery disease patients and 167 disease-free control patients. In univariable analyses, there was a strong association between coronary status and extent of carotid artery disease in men and women older than and younger than 50 years (p less than 0.001 for men and women greater than 50 years, p less than 0.001 for women less than or equal to 50 years, p = 0.045 for men less than or equal to 50). The relation remained strong after control for age in men and women older than 50 years and in women younger than 50 (p less than 0.001 for men and women greater than 50 years, p = 0.003 for women less than or equal to 50) but did not persist after control for age in men younger than 50. Logistic models that included coronary disease risk factors, with or without B-mode score, as independent variables and presence or absence of coronary disease as the outcome variable indicated that the extent of carotid atherosclerosis was a strong, statistically significant independent variable in models for men and women older than 50 years of age. Next, we examined the usefulness of B-mode score as an aid in screening for coronary artery disease in men and women older than 50 years. Classification rules, both including and excluding B-mode score, were developed based on logistic regression and, for comparison, recursive partitioning (decision trees). The performance of these rules and the bias of their performance statistics were estimated. The improved classification of the study sample when B-mode score was incorporated in the rule was statistically significant only for men (p = 0.015). However, the addition of B-mode score was found to 1) increase the median discrimination score for both sex groups based on the logistic model, and 2) yield better sensitivities and specificities for rules based on recursive partitioning. Thus B-mode score is strongly, consistently, and independently associated with coronary artery disease in patients older than 50 and is at least as useful as well-known risk factors for identifying patients with coronary artery disease.

Extracranial carotid atherosclerosis in patients with and without transient ischemic attacks and coronary artery disease.

We examined the extent of extracranial carotid atherosclerosis as evaluated by a B-mode ultrasound score in four groups of hospitalized patients: hospital controls free of both cerebrovascular symptoms and coronary atherosclerosis (HC, n = 245); patients with coronary atherosclerosis but without cerebrovascular symptoms (CAD, n = 382); patients with transient ischemic attacks but asymptomatic for coronary atherosclerosis (TIA, n = 107); and patients having both transient ischemic attacks and symptomatic coronary events (TIA + CAD, n = 39). The unadjusted B-mode scores were lowest for the HC group, intermediate for the CAD group, and highest for the TIA or TIA + CAD groups (no difference between these two groups). However, after adjustment for age (or age and other risk factors), we could find no significant differences among the CAD, TIA, and TIA + CAD groups, while the HC group had significantly lower adjusted scores. These data suggest that 1) accentuated development of carotid atherosclerosis is associated with both TIA and CAD and 2) the apparent differences in extracranial carotid atherosclerosis between coronary and cerebrovascular patients are partly attributable to differences in risk factor profiles (most notably age). The potentially accentuated rate of development of extracranial atherosclerosis in patients with CAD mandates a low threshold for cerebrovascular evaluation in CAD patients.

Extracranial carotid atherosclerosis in black and white patients with transient ischemic attacks.

To evaluate the association between extracranial carotid atherosclerosis, race, and transient ischemic attack, we carried out a retrospective hospital chart review and quantified the extent of noninvasively determined extracranial carotid atherosclerosis in 25 black patients greater than 45 years old with transient ischemic attacks. Two sex- and age-matched white patients with transient ischemic attacks were similarly studied for each black patient. Extent of extracranial carotid atherosclerosis (expressed as B-mode score) was similar for blacks and whites. B-mode score was only slightly less in patients with posterior- than in those with anterior-circulation transient ischemic attacks. Fifty-six patients (35 white, 21 black) had unilateral anterior-circulation transient ischemic attacks. Of the 32 patients with more extensive extracranial carotid atherosclerosis ipsilateral to the affected hemisphere, 23 (66% of 35) were white; only nine (43% of 21) were black. In the 35 white patients, the extent of disease in the ipsilateral carotid artery was significantly greater (p less than 0.03) than that in the contralateral carotid artery. When B-mode scores in the left and right carotid arteries were combined for the subgroup of patients with unilateral anterior-circulation transient ischemic attacks, blacks had slightly more atherosclerosis in the extracranial arteries than whites.

Changes in pharmacologic treatment of hyperlipidemia.

We evaluated the changes in frequency of pharmacologic treatment of hyperlipidemia in 345 hyperlipidemic patients with symptomatic cardiovascular disease requiring cardiac catheterization between 1982 and 1987. The frequency of pharmacologic treatment increased from 13% (1982) to 59% (1987), with the major increase occurring in 1984. Increases in the frequency of treatment were paralleled by increases in prescriptions for lipid-lowering drugs nationwide. During this period the percentage of hyperlipidemic patients we evaluated who were treated with various agents changed, and at the end of the study the use of gemfibrozil, bile acid-binding resins, and nicotinic acid had increased, whereas clofibrate and probucol use decreased. Although the data showed an increase in prevalence of treatment, almost half the patients remained untreated, and of those treated over half remained hypercholesterolemic despite treatment. The results suggest increasing but incomplete physician awareness of hyperlipidemia as a cardiovascular disease risk factor and the need for further physician education in the pharmacologic management of hyperlipidemia.

Selection of neighborhood controls for a study of coronary artery disease.

This report describes the selection process for a neighborhood control group recruited between February 1985 and July 1986 to augment a hospital-based case-control study investigating the relation of traditional and nontraditional risk factors to coronary artery atherosclerosis. A total of 219 cases with angiographically defined coronary artery disease residing within a 60-mi (96-km) radius of Winston-Salem, NC, were assigned to surveyors to be matched. Thirty-seven per of the study population were rural, 92% were white, 58% were male, and 52% were older than 50 years of age. One hundred and eighty-seven controls were age-(+/- five years), sex-, and race-matched pairwise to cases. After locating the residence of the case, the surveyor systematically visited neighboring households to ascertain eligibility status of residents. To achieve a match, a maximum of three visits was made to the neighborhood; up to 25 households were surveyed per visit. Refusal rate was less than 5% of eligible matches. Young white urban males were the easiest to match, while rural females, especially older persons, were the most difficult. Average time to complete an assignment included 129 minutes for travel, 237 minutes for surveying the neighborhood, and 62 minutes for clerical tasks. Average distance traveled was 85 mi (136 km) per case. As expected, the time and distance to complete a case were greater in rural than urban areas. The average cost per case was $122.97.

Caffeine in human milk and in serum of breast-fed infants.

A study was carried out to determine the caffeine concentration in milk of lactating women ingesting known amounts of caffeine and to determine serum concentration of caffeine of their infants. 9 lactating women and their infants were studied for 9 days. For the first 5 days, the women ingested 750 mg of caffeine daily, and for the next 4 days they ingested no caffeine and avoided coffee and other caffeine-containing products. The concentration of caffeine in samples of milk obtained by pooling aliquots from each feeding on day 5 averaged 4.3 micrograms/ml for 7 mothers who were 11-22 days after delivery on the 1st day of study. Values ranged from nondetectable (less than 0.25 micrograms/ml) to 15.7 micrograms/ml. No caffeine was detected in milk samples obtained on day 9. The mean concentration of caffeine in sera of the infants on day 5 was 1.4 micrograms/ml (range: nondetectable to 2.8 micrograms/ml). Caffeine was still detectable in 2 infants' sera obtained on day 9. Concentrations had decreased only slightly since day 5. 2 older infants and their mothers were studied as described except that on days 5 and 9 samples of milk were obtained from each feeding and analyzed individually. The average caffeine concentrations in milk consumed on day 5 were 13.4 and 28.6 micrograms/ml, respectively. The concentrations of caffeine in infants' sera on day 5 were less than 0.25 and 3.2 micrograms/ml. On day 9 milk and serum caffeine levels were below the limits of detectability.

Effect of maternal caffeine consumption on heart rate and sleep time of breast-fed infants.

Eleven mother-infant pairs were studied to determine the effect of maternal caffeine ingestion (500 mg/day) on heart rate and sleep time of the infants. In a balanced cross-over design, mothers ingested 5 cups of decaffeinated coffee daily during one 5-day period and 5 cups of decaffeinated coffee with added caffeine (100 mg/cup) during another 5-day period. Concentrations of caffeine in milk on the last day of the caffeine period ranged from 1.6 to 6.2 micrograms/ml and the intake of caffeine by the infants was estimated to be 0.3-1.0 mg/kg/day. Infant serum did not contain detectable amounts of caffeine on the last day of either experimental period. Performance during the caffeine and no-caffeine periods was not significantly different with respect to either 24-hour heart rate or sleep time.