Radioresistance of the Enhancing Effect of Cells from Carrier-Immunized Mice in an In Vitro Primary Immune Response

The in vitro primary response of mouse spleen cell suspensions to 2,4,6-trinitrophenyl(Tnp)-erythrocytes has been studied. The number of anti-Tnp plaque-forming cells that arise after antigenic stimulation in vitro is greatly enhanced by prior immunization in vivo with the carrier erythrocyte. The enhancement is antigen specific. The priming for an enhanced response can be elicited with very low antigen doses and is often apparent 24 hr after immunization. It is marked from day 3 to day 14. Spleen cells from carrier-primed mice will enhance the anti-Tnp response of normal cells when mixed cultures of the two cell populations are challenged with Tnp-erythrocytes in vitro. The carrier-primed cells mediating this enhancing effect are thymus derived.The development of the thymus-derived, carrier-specific cell population has been generally assumed to involve the antigenic stimulation of cell proliferation. It was, therefore, somewhat surprising to find that the enhancing effect of the carrier-primed cells, once they had been generated, is not inhibited by x-irradiation.     

A Platelet-Dependent Serum Factor That Stimulates the Proliferation of Arterial Smooth Muscle Cells In Vitro

Dialyzed serum from clotted monkey blood ("blood serum") promotes the proliferation of monkey arterial smooth muscle cells in culture, but dialyzed serum prepared from recalcified platelet-poor plasma ("plasma serum") is much less effective. Addition of platelets and calcium to platelet-poor plasma increases the activity of plasma serum to the same level achieved with blood serum. Furthermore, addition to plasma serum of a platelet-free supernatant prepared by exposing purified platelets to thrombin also stimulates the proliferation of smooth muscle cells. Thus, much of the growth-promoting activity of dialyzed serum is directly or indirectly derived from platelets. This finding has important implications for the response of arteries to localized injury and provides a key to further understanding of the role of factors derived from blood serum in promoting cell proliferation in vitro.     

Immune Response and the Tumor Microenvironment: How They Communicate to Regulate Gastric Cancer

Gastric cancer is the second most common cause of cancer-related death in the world. A growing body of evidence indicates that inflammation is closely associated with the initiation, progression, and metastasis of many tumors, including those of gastric cancer. In addition, approximately 60% of the world''s population is colonized by Helicobacter pylori, which accounts for more than 50% of gastric cancers. While the role of inflammation in intestinal and colonic cancers is relatively well defined, its role in stomach neoplasia is still unclear because of the limited access of pathogens to the acidic environment and the technical difficulties isolating and characterizing immune cells in the stomach, especially in animal models. In this review, we will provide recent updates addressing how inflammation is involved in gastric malignancies, and what immune characteristics regulate the pathogenesis of stomach cancer. Also, we will discuss potential therapeutics that target the immune system for the efficient treatment of gastric cancer.     

In Primary Aldosteronism the Circadian Blood Pressure Rhythm is Similar to That in Primary Hypertension

To investigate whether the 24-hour blood pressure (BP) profile of primary aldosteronism differs from that of primary hypertension, ambulatory BP monitoring was performed in 11 patients with primary aldosteronism (9 with an adrenal adenoma and 2 with idiopathic hyperaldosteronism) and in 11 primary hypertensives, matched for sex (5M,6F), age (mean: 52 vs 49 yrs) and casual BP. We found no difference in 24-hour BP, nocturnal BP fall, BP variability (standard deviation and peaks of pressure) response to postural changes (lying-standing BP) between the two groups (all p values n.s.). Within the patients with primary aldosteronism no correlation was observed between BP, plasma renin activity, blood and urine aldosterone levels, blood and urine K⁺, and size of the tumour. Thus, at variance with previous reports, these results show that diurnal rhythm of BP and BP variability are similar in primary aldosteronism and primary hypertensives with similar demographic features and casual BP levels. They also show that an orthostatic fall of BP is not a common feature in this disease.     

Immunoglobulin Synthesis In Vitro by Lymphocytes from Patients with Immune Deficiency: Requirement for a Special Serum Factor

Certain patients with immune deficiency were encountered whose peripheral blood lymphocytes included no immunoglobulin-bearing cells. However, other markers of B type lymphocytes were observed; lymphocytes isolated free of macrophages showed the presence of receptors for the Fc fragment of IgG and for the third component of complement. One patient with a syndrome of thymoma and severe hypogammaglobulinemia was studied in special detail. In vitro the patient's cells were able to develop surface Ig in media supplemented with fetal-calf serum or normal human serum; in media supplemented with autologous serum, the cells developed no surface Ig. During culturing antigenic determinants of immunoglobulin became detectable in the medium, and both medium and cell-surface immunoglobulin underwent a shift from specific IgM determinants early in the culture period to IgG and IgA determinants later. Normal lymphocytes and thymocytes activated by concanavalin A repaired the deficiency in the patient's serum. These data support the concept that a factor possibly derived from T cells is missing from this patient's serum and that this factor is required for the maturation of the B cell for immunoglobulin synthesis.A patient with X-linked agammaglobulinemia had a population of circulating lymphocytes with some surface characteristics that appeared similar to those of the B cells from the patient with thymoma. In contrast, however, no Ig synthesis by this patient's cultured cells could be demonstrated. The possible nature of the lymphocytes reacting with aggregated IgG in this case is discussed.     

Rhythmic Melatonin Response of the Syrian Hamster Pineal Gland to Norepinephrine In Vitro and In Vivo

Norepinephrine (NE, 10(-6) M) stimulated melatonin accumulation in the incubation medium of rat (but not Syrian hamster) pineals taken at the end of the light phase. However, NE elevated melatonin accumulation in the medium of pineals taken after 20 min of light exposure of animals of either species at 6 h into the 10-h dark phase. A dose response to 10(-7)-10(-5) M NE was observed in both the medium and pineals upon incubation of pineals taken from rats at 4 h into the light phase and from hamsters after 20 min light exposure at 6 h into the dark phase. Approximately 95% of the melatonin present was in the medium. The incubation time was 4 h in all cases. Subcutaneous injection of 1 microgram/g NE (either at the end of the light phase or after 30 min of light at 6 h into the dark phase) did not stimulate in vivo Syrian hamster pineal melatonin content determined 1 or 2 h after injection, whether the hamsters were placed in light or darkness after the injection. However, after 30 min of light beginning at 6 h into dark, injection of 5 micrograms/g desipramine (DMI, a blocker of catecholamine uptake into nerve endings) allowed a dramatic hamster pineal melatonin response to additional injection of 1 microgram/g NE, observed at 1 and 2 h in light after injection. A small effect of DMI alone was seen. DMI also potentiated the effect of NE (each 10(-6) M) on melatonin accumulation in the medium of incubated hamster pineals taken after a short light exposure at night. No significant stimulatory effect of NE and/or DMI was seen in vivo or in vitro near the middle of the light phase. Measurement of melatonin in the incubation medium is a useful method for studying pineal function. The Syrian hamster pineal has rhythm of sensitivity to NE (sensitivity evident at night) and even at night is protected by neuronal uptake from circulating NE-induced stimulation of melatonin production. NE appears to be the neurotransmitter for stimulation of pineal melatonin production in the Syrian hamster. The sensitivity rhythm and uptake protection might provide specificity of control of the nightly melatonin signal by reducing the chance of a melatonin response during the day or a response to circulating catecholamines from general sympathetic stimuli.     

Effect of Dietary Calcium on In Vitro Aortic Tissue Responsiveness to a Hypertensive Factor

It has been proposed that calcium supplementation in the diet is associated with a reduction in blood pressure. In the present study, we investigated vascular tissue sensitivity to a hypertensive factor (HF) in spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY) fed a high calcium diet, a low calcium diet and a food restricted diet. HF, which has been isolated from erythrocytes, increases blood pressure when injected into normotensive rats and stimulates calcium uptake by aortic rings in vitro. Five-week-old rats were divided into the following groups: SHR and WKY fed a regular diet (1% calcium), SHR and WKY fed a high calcium diet (4% calcium), SHR and WKY fed a low calcium diet (0.02% calcium) and SHR and WKY fed a regular diet (1% calcium) in which food intake was restricted to 65% of ad libitum intake. Food intake, body weight, urine phosphate excretion and blood pressure development were followed for 8 weeks. At sacrifice, plasma levels of calcium and phosphate were determined. Tissue responsiveness to HF was calculated by incubating aortic rings from the rats in the different groups with HF and measuring lanthanum-resistant calcium uptake. A 4-fold increase in dietary     

Antibody Response In Vitro to an Animal Virus: Production of Rabies Virus Neutralizing Antibodies by Mouse Cells in Culture

Rabies virus neutralizing antibodies were produced in vitro by the exposure of mouse spleen cells to live and inactivated rabies virus suspensions and to sheep erythrocytes coated with rabies virus. These antibodies did not neutralize two other rhabdoviruses: Kern Canyon and vesicular stomatitis viruses, and were precipitable by treatment with an antiserum to mouse IgG. Removal of "glass-adhering" cells from mouse spleen cell suspensions abolished the antibody response, which could be restored by the addition of mouse peritoneal exudate cells, rich in macrophages.     

Role of Tissue Factor in Adhesion of Mononuclear Phagocytes to and Trafficking Through Endothelium In Vitro

An in vitro model consisting of endothelium grown oncollagen was used to investigate how mononuclear phagocytes traverse endothelium in the basal-to-apical direction (reverse transmigration), a process that mimics their migration across vascular and/orlymphatic endothelium during atherosclerosis and resolution ofinflammation, respectively. Monoclonal antibody (MoAb) VIC7 againsttissue factor (TF) inhibited reverse transmigration by 77%.Recombinant tissue factor fragments containing at least six amino acidsC-terminal to residue 202 also strongly inhibited reversetransmigration. TF was absent on resting monocytes but was induced onthese cells after initial apical-to-basal transendothelial migration.Two additional observations suggest that TF is involved in adhesion between mononuclear phagocytes and endothelium: (1) when monocytes wereincubated with lipopolysaccharide (LPS) to stimulate expression of TFbefore they were added to endothelium, VIC7 or soluble TF modestlyinhibited their adhesion to the apical endothelial surface, each byabout 35%; and (2) endothelial cells specifically bound to surfacescoated with TF fragments containing amino acids 202-219. This bindingwas blocked by anti-TF MoAb, suggesting that endothelial cells bear areceptor for TF. These data suggest that mononuclear phagocytes use TF, perhaps as an adhesive protein, to exit sites ofinflammation.