Arnis Richters

Inhalation of NO2 and Blood Borne Cancer Cell Spread to the Lungs

An experimental model was designed where the frequency of blood-borne cancer cell metastases to the lungs of animals was used as an indicator to detect adverse effects of inhaled nitrogen dioxide (NO2). Animals were exposed to air containing 0.40 +/- 0.05 ppm or 0.80 +/- 0.05 ppm of NO2. After the appropriate exposure periods, the animals were infused intravenously with B16 mouse melanoma cells. At 3 wk post-infusion the animals were killed and the lungs were examined for melanoma nodule development. The lungs of the NO2-exposed animals contained a significantly higher number of melanoma nodules than the lungs of control animals (P less than .0025). These results indicate that inhalation of ambient or near ambient levels of NO2 influences the metastasis of blood-borne cancer cells. This raises the possibility that similar events may occur in the human population.

Surface immunoglobulin positive lymphocytes in human breast cancer tissue and homolateral axillary lymph nodes

Surface immunoglobulins were determined on human lymph node lymphocytes by the use of immunofluorescence technique in 59 breast cancer patients undergoing radical mastectomy. In 10 of these cases, lymphocyte surface immunoglobulins were also studied on lymphocytes infiltrating the primary cancer mass. The most outstanding finding was a difference between the IgM lymphocyte populations in the lymph nodes of patients with and without lymph node metastases. When cancer tissue was present in one or more lymph nodes, the tumor‐free as well as the tumor‐positive nodes showed a higher percentage of IgM positive lymphocytes than did lymph nodes from patients without nodal metastases. The greatest difference was found when IgM lymphocytes from tumor‐bearing lymph nodes were compared with those from the lymph nodes of patients without nodal metastases (p < .005). The lymphocyte populations infiltrating 5 of the 10 primary cancer masses studied showed no surface immunoglobulins; in the remainder, both IgG and IgM positive lymphocytes were found but in variable proportions. While the findings are not definitive, this is the first study dealing with the quantitation of immunoglobulin specific lymphocytes in the lymph nodes and tumor tissue of patients with breast cancer.

A new relationship between air pollutant inhalation and cancer.

Many studies have been conducted to investigate the effects of different air pollutants on health. Our studies have focused on the effects of nitrogen dioxide (NO2), and recently we reported that inhalation of low levels of NO2 can facilitate cancer cell metastasis. The study described herein utilized the same B16 mouse melanoma metastasis model of previous investigations, but under different NO2 exposure conditions. The results provide further evidence that inhalation of ambient level NO2 (0.4 ppm) or polluted urban ambient air play a role in facilitation of blood-borne cancer cell metastasis. In addition, results show different patterns of melanoma cell distribution in the lungs of NO2- and ambient-air exposed animals. They also indicate that extended periods of clean air between NO2 exposures may diminish the severity of the insult in the less sensitive animals. It is our conclusion that the results provide strong support for the need of improved air quality and for reduction of noxious pollutants in urban ambient air.

Reduction in T lymphocyte subpopulations following acute exposure to 4 ppm nitrogen dioxide

The effect of acute exposure to nitrogen dioxide (NO2) on splenic T lymphocyte subpopulations was studied in C57BL/6cum mice. The mice were exposed to 4 ppm NO2 for 8 hr. Monoclonal antibodies to T lymphocyte differentiation antigens and fluorescence-activated cell sorter (FACS) analysis were used to detect changes in T lymphocyte subpopulations. Percentages of total T lymphocytes (Thy-1.2-positive), T-helper/inducer lymphocytes (L3T4-positive), and T-cytotoxic/suppressor lymphocytes (Lyt-2-positive) were significantly lower in NO2-exposed animals than in filtered-air-breathing controls. Large T-cytotoxic/suppressor cells were found to be the most susceptible subpopulation. Spleen and body weights of the mice were also determined. There were no differences between body weights of control and exposed animals; however, exposed mice had significantly lower spleen weights. This is the first report providing evidence linking alterations in T lymphocyte subpopulations to acute NO2 exposure at occupational levels. T lymphocytes play a central role in regulatory and effector immunological functions such as mediating delayed hypersensitivity, regulating immunoglobulin production, and lysing virus-infected and neoplastic cells. The biological significance of these findings remains to be established, but it is very likely that functional impairment occurs since an optimal immune response depends upon a proper balance of the T lymphocyte subpopulations. Detection of alterations in T lymphocyte subpopulations using monoclonal antibodies and FACS analysis may provide an extremely sensitive means of demonstrating NO2-induced changes in the immune system.

The significance of autochthonous lymphocyte interactions with human breast cancer cells in primary tissue cultures

Short‐term primary tissue cultures of 16 human breast cancers were employed to study cancer cell interactions with autochthonous lymphocytes. Attention was given to 4 lymphocyte interactions, 1 random and 3 special forms, i.e., clustering, congregation, and emperipolesis. Stained tissue culture preparations were used to count the total number of cancer cells and the frequencies of the different lymphocyte interactions with the cancer cells. Comparisons were made of interactions of 2 groups of autochthonous lymphocytes—those already present in the explant of cancer tissue and those of homolateral axillary lymph node origin which were added to the nutrient media. Where lymphocytes were not added, only 29% of the cases had one or more preparations positive for interactions, whereas the corresponding figure for the group with added lymphocytes was 65%. In addition, the frequency of the interactions within each of the positive preparations was increased fourfold. Furthermore, in those preparations where an increased frequency was noted, the yield of viable cancer cells was significantly less than that found in the corresponding cultures without added lymphocytes. Conversely, an increase in cancer yield occurred in those cultures where the addition of lymphocytes failed to increase the frequency of interactions. These and other findings dealing with distinctive lymphocyte responses of an individual to his own cancer provide insight into host defense mechanisms not otherwise available.

Depression of stimulated arachidonate metabolism and superoxide production in rat alveolar macrophages following in vivo exposure to 0.5 PPM NO2

Alveolar macrophages (AM) have been found to suffer significant functional deficits in response to nitrogen dioxide (NO2) exposure. The present investigation examined changes in the activation of AM arachidonate metabolism and superoxide production in response to an environmentally relevant level of NO2. Rats were exposed to 0.5 ppm NO2 for periods of 0.5-10 d and AM were obtained by bronchoalveolar lavage (BAL). NO2 exposure produced complex effects upon both unstimulated and stimulated AM arachidonate metabolism. Unstimulated AM synthesis of leukotriene B4 (LTB4) was depressed rapidly within 1 d of exposure, and depressed again at 5 d. Alveolar macrophage production of thromboxane B2 (TxB2), LTB4, and 5-hydroxyeicosatetraenoate (5-HETE) in response to stimulation with the calcium ionophore, A23187, were acutely depressed within 1 d of exposure; however, generation of these compounds recovered to air-control levels with longer exposure, while 5-HETE was increased at 10 d. In contrast, AM production of LTB4 in response to another stimulus, zymosan-activated rat serum (ZAS), was not depressed until following 5 d of exposure and remained slightly lower than air-control levels at 10 d. Levels of TxB2, LTB4, prostaglandin E2 (PGE2), and prostaglandin F2 alpha (PGF2 alpha) measured in BAL fluid (BALF) were found to be depressed within 4 h of exposure, suggesting an acute decrease in the in vivo pulmonary arachidonate metabolism; however, production of these compounds generally recovered to air-control levels with longer exposure. The AM superoxide production stimulated by phorbol myristate acetate (PMA) was decreased rapidly and continuously throughout the study. Thus, exposure to a low concentration of NO2 acutely depresses activation of AM arachidonate metabolism and superoxide production in response to external stimuli, and may impede defense against pulmonary infection.

Ambient level ozone effects on subpopulations of thymocytes and spleen T lymphocytes

The effects of ozone on thymocyte and spleen T lymphocyte subpopulations were studied. Balb/c mice were exposed to clean air or to 0.3 +/- 0.05 ppm ozone for 1-3 wk. Thymocytes and spleen T cells were stained with fluorochrome conjugated monoclonal antibodies against surface differentiation markers and/or propidium iodide for deoxyribonucleic acid (DNA). The cells were then analyzed by fluorescence activated cell sorter. The percentages of certain thymocyte and spleen T lymphocyte subtypes and DNA synthesizing spleen T cells were lower following 1 wk of ozone exposure. After 3 wk exposure, the thymocyte percentages were higher in ozone-exposed mice, whereas the absolute number remained lower, and spleen T lymphocytes showed no changes. The findings suggest that short-term ozone inhalation can affect the T cell immune system adversely, particularly the CD4+ cells.

Spleen changes in animals inhaling ambient levels of nitrogen dioxide

The effects of ambient levels of NO2 on the spleens of adult and newborn Swiss Webster (S/W) mice were determined. Spleens were evaluated by the following criteria: (1) spleen weight, expressed as a percent of the body weight (% spleen weight), (2) size of the spleen lymphoid nodules as determined by computed image analysis, (3) spleen cell counts, and (4) histopathologic evaluation. Data for NO2-exposed animals were compared with data for control animals that inhaled filtered air. Totals of 217 control and 217 NO2-exposed animals were studied. After 6 wk of exposure to NO2 at ambient levels (0.35 +/- 0.05 ppm), the following significant changes were observed in the spleens of exposed mice: (1) increase in % spleen weight (p less than 0.0025), (2) increase in size of spleen lymphoid nodules (p less than 0.01), (3) smaller increase in spleen cell number per given weight increment of spleen as determined by correlation coefficients (p less than 0.0125) and linear regression analysis of spleen cell counts, and (4) an apparently greater predominance of red cells in the red pulp. It is concluded that inhalation of NO2 is associated with quantifiable spleen changes, which may prove to be useful indicators for assessing effects of inhaled NO2.

Centriacinar region inflammatory disease in young individuals: a comparative study of Miami and Los Angeles residents

Abstract Semiquantitative measurements of chronic inflammation of the centriacinar region (proximal acinus of lung) were compared between 20 Miami and 18 Los Angeles residents (ages 11–30 years) for whom smoking histories were available. Mean extent and severity scores of four lung sites were higher for Los Angeles than Miami residents, with effect of city statistically significant for extent (P=0.02). Also, maximum scores for extent and severity by city were significantly greater for Los Angeles residents (P=0.02, each), but not by smoking history. Smokers did have higher scores for mean extent and severity (by lung site and smoking history), but neither this nor inclusion of smoking and city in the model reached significance. With respect to maximum extent and maximum severity scores, a stratified comparison of cities by smoking history showed a trend (not significant) toward higher scores for Los Angeles residents. Mean extent and severity scores for the lower lobe were higher for basilar sections than for apical sections (each P<0.001). Cumulative data indicate that expanded pathologic studies are essential for efforts to complete a convergence of epidemiological and experimental data implicating exceedences of the Federal ozone standard as a contributor to human lung injury.

Human Lung Cancer in Tissue Culture

Most epithelial lung cancers are believed to originate from the bronchial mucosa, and these “bronchogenic carcinomas” have been subdivided into three major entities, epidermoid cancer, adenocarcinoma, and undifferentiated carcinoma. While more elaborate classifications have been proposed, in particular that by the World Health Organization (Kreyberg et al., 1967), criteria for distinguishing the subtypes have not been universally accepted or uniformly applied. As a consequence, there has been a tendency to overlook the great diversity of cancer cell types within the lung. At the root of the problem is the little attention being given to the numerous and distinctive normal cells of the “pneumothelium,” i.e., the respiratory tract lining from the bronchus into the alveolus. Some progress has been made with the advent of electron microscopic studies of both nonneoplastic and neoplastic tissues of the lung. Of special interest is the discovery that the “oat-cell” cancer is derived from the Kultschitsky cell of the bronchial mucosal lining and submucosal glands (Bensch et al., 1968). Also, it now appears that one type of “bronchioloalveolar” cancer originates from type 2 pneumocytes of the alveolus (Adamson et al., 1969; Coalson et al., 1970). However, these two types of lung cells are the only ones that have been identified as “parent cells” for human lung cancers.