Association of polymorphonuclear leukocytes with sites of aortic catheter-induced injury in rabbits

The kinetics of the association of polymorphonuclear leukocytes (PMNs) with arterial balloon catheter-induced injury have been examined. An average of 6 X 10(7) PMNs were isolated from 20 ml of blood and labelled with 111In-oxine for reinfusion into the donor rabbit. The cells remained viable as demonstrated by both in vitro and in vivo tests of cell function. The abdominal aorta of rabbits was denuded of endothelium and immediately, 24 h, or 5 weeks later, exposed to autologous radiolabelled PMNs for 1 h. The presence of PMNs at sites of denudation was demonstrated by detection of the radioactive label and was confirmed by light and electron microscopy after 24 h, but not at 5 weeks. Immediately following denudation radioactivity was 2.44 +/- 0.33 times control (P = 0.006); 2.52 +/- 0.18 at 24 h (P = 0.005); and 1.88 +/- 0.32 times control at 5 weeks (P = 0.045). The presence of PMNs, or their products, 5 weeks after denudation suggests a more complex role of PMNs and possibly a direct involvement in the long term changes resulting from arterial balloon catheter injury.     

The fluosol-perfused isolated canine pancreas: a model for the study of blood component effects in acute pancreatitis

Blood components have been implicated as factors which modulate organ injury in acute pancreatitis. To isolate these effects we compared a standardized isolated, blood-perfused, canine pancreas model as described by Herman-Taylor and modified by Cameron with a model using fluosol, a fluorocarbon, as the perfusate. Pancreatitis was induced using partial pancreatic duct obstruction with secretin induced hypersecretion. Twenty-four dogs were randomized into four groups; (1) blood-perfused control (BPC), (2) fluosol-perfused control (FPC), (3) blood-perfused injury (BPI), (4) fluosol-perfused injury (FPI). All glands were observed for 4 h for mean arterial pressure (MAP), weight gain, gross appearance, and venous amylase. Stability was monitored with blood gases and glucose. Specimens were taken at 4 h for light and electron microscopy. Results: BPI preps had a significantly higher vascular resistance at 3 and 4 h compared to FPI preps (3.85 vs 3.26 PRU and 4.8 vs 3.9 PRU, respectively) (P less than 0.002). Edema formation (3+ vs 1+) and venous amylase (18,543 vs 1961) (P less than 0.001) were greater in BPI than FPI preps. Light and electron microscopy confirmed injury but could not quantify it between injury groups. Summary: Hypersecretion and partial ductal obstruction causes a more severe injury in the blood than the fluosol perfused preparation. Changes in the peripheral resistance seen in the blood perfused model lend support to the theory that the primary injury in this model is at the capillary level and is modulated by a blood component.     

Longitudinal,population-based study of racial/ethnic differences in colorectal cancer survival: impact of neighborhood socioeconomic status,treatment and comorbidity

Background  

Colorectal cancer, if detected early, has greater than 90% 5-year survival. However, survival has been shown to vary across racial/ethnic groups in the United States, despite the availability of early detection methods.     

Period, age, and cohort effects on substance use among young Americans: a decade of change, 1976-86

In an earlier article in this Journal, we reported analyses that differentiated among period, age, and cohort effects on substance use among American youth 18 to 24 years old, from the high school classes of 1976 to 1982 during the period of 1976 to 1982. The present analyses extend the classes and years to 1986, and the age range to 18-28. A cohort-sequential design is employed, based on annual surveys of nationally representative samples of high school seniors, plus annual follow-up surveys of each senior class. Twelve different classes of drugs, both licit and illicit, are examined. Several different types of period, age, and cohort effects over the last decade are identified. Alcohol use (monthly and occasions of heavy use), and the use of marijuana, cocaine, amphetamines, methaqualone, barbiturates, LSD, psychedelics other than LSD, and tranquilizers all showed period effects. Occasions of heavy drinking, cigarette smoking, monthly and daily use of alcohol, and annual prevalence of cocaine, amphetamines, barbiturates, LSD, and narcotics other than heroin showed age effects. Class effects were seen for cigarette smoking and daily marijuana use.     

Race and mammography use in two North Carolina counties.

OBJECTIVES: This study investigated racial differences in mammography use and their association with physicians' recommendations and other factors. METHODS: The study used 1988 survey data for 948 women 50 years of age and older from the New Hanover Breast Cancer Screening Program. Racial differences in terms of physician recommendation, personal characteristics, health characteristics, and attitudes toward breast cancer and mammography were examined. Factors at least minimally associated with race and use were included in multivariate logistic regression analyses to examine the effect of race while controlling for other factors. RESULTS: In comparison with White women. Black women were half as likely to report ever having had a mammogram (27% vs 52%) and having a mammogram in the past year (17% vs 36%). Black women also significantly less often reported physician recommendation (25% vs 52%). Although Black and White women differed significantly in other characteristics, multivariate logistic regression analyses indicated that physician recommendation accounted for 60% to 75% of the initial racial differences in mammography use. CONCLUSIONS: Understanding physicians' recommendations for breast cancer screening is a critical first step to increasing mammography use in disadvantaged populations.     

Nitrates in the elderly. Pharmacological considerations.

Although a significant proportion of patients receiving nitrates are elderly, surprisingly little published work is available describing the pharmacokinetics and pharmacodynamics of these agents in elderly patients. The lack of pharmacokinetic data is related to the difficulty in assaying nitrates and there are at present no definitive data describing the effect of aging on their bioavailability or elimination. A common finding in old age is of decreased hepatic first-pass metabolism. This would affect isosorbide-2-mononitrate and isosorbide-5-mononitrate less than isosorbide dinitrate and nitroglycerin (glyceryl trinitrate). Venous responsiveness to nitrates does not appear to alter with age, so that pharmacodynamic properties would not be expected to alter. However, decreased baroreflex function causes an increased tendency for posturally related side effects to occur. Mechanisms of tolerance are likely to be unaltered but any possible alteration in quantitative aspects of tolerance has not been studied. Nitrate therapy in the elderly would benefit from systematic investigation. At the moment, therapy needs to be titrated to the individual patient, with care taken to avoid age-related side effects by careful initiation of therapy and appropriate reviews of each patient.     

Solitary bronchioloalveolar carcinoma: CT criteria

The computed tomographic (CT) scans of 30 patients with solitary bronchioloalveolar carcinoma were reviewed. Common features at CT included the peripheral or subpleural location of a pulmonary mass (25 cases), pseudocavitation (18 cases), heterogeneous attenuation (17 cases), irregular margins forming a star pattern (22 cases), and pleural tags (21 cases). Using these CT criteria, four independent observers attempted to identify cases of bronchioloalveolar carcinoma from a larger sample of lung cancers and benign lesions by categorizing a series of test cases into four probability categories. Although the bronchioloalveolar carcinomas were correctly ranked in the two highest probability categories 75% of the time (in 45 of 60 cases), there was considerable overlap with other lung lesions, particularly with adenocarcinoma and large cell undifferentiated carcinoma. However, even though the typical features of bronchioloalveolar carcinoma are not invariable or highly specific, they are characteristic enough to suggest the diagnosis.