Cytotoxic reaction, allergic reactions

Mean arterial pressure and cardiac output, an expression of the amount of blood that the heart pumps each minute, are the key Indicators of the normal functioning of the cardiovascular system. Mean arterial pressure is strictly controlled, but by changing the cardiac output, a person can adapt, e.g., to increased oxygen requirement due to increased workload. Blood flow in vital organs may vary for many reasons, but is usually due to decreased cardiac output. However, there can be very dramatic changes in blood pressure, e.g., blood pressure plummets during an anaphylactic allergic reaction. Also cytotoxic chemicals, such as heavy metals, may decrease the blood pressure. 

In this type of reaction an antigen elicits the generation of cytotoxic T-lymphocytes ( immune defense). Cytotoxic T-lymphocytes (Tc) destroy antigen bearing cells by inducing apoptosis. This reaction can be viewed as the cellular counterpart to the humoral Type II reactions. They play an important physiological role in the defense of viruses, and can become allergic reactions under the same conditions as described for Type II reactions. 

Leucovorin (folinic acid) - enzyme cofactor for thymidylate synthase rescues from methotrexate toxicity potentiates cytotoxicity of fluoro— pyrimidines -occasional nausea -skin rash -headache -rare allergic reactions... 

Most anaphylactoid reactions are due to a direct or chemical release of histamine, and other mediators, from mast cells and basophils. Immune-mediated hypersensitivity reactions have been classified as types I-IV. Type I, involving IgE or IgG antibodies, is the main mechanism involved in most anaphylactic or immediate hypersensitivity reactions to anaesthetic drugs. Type II, also known as antibody-dependent hypersensitivity or cytotoxic reactions are, for example, responsible for ABO-incompatible blood transfusion reactions. Type III, immune complex reactions, include classic serum sickness. Type IV, cellular responses mediated by sensitised lymphocytes, may account for as much as 80% of allergic reactions to local anaesthetic. 

The four types of allergic reactions are anaphylactic, cytotoxic, immune complex, and cell mediated. 

There is normally a delay of several hours between the exposure to ricin and the onset of clinical symptoms, but the cytotoxic effects may not occur until two to five days after ingestion. In contrast, certain individuals may display allergic reactions almost immediately after exposure, and this is presumed to be related to the glycoproteins that the beans contain. Episodes of asthma have been linked to the inhalation of ricin dust at castor bean mills — in one incident in 1952 at Bauru in Brazil, 150 people living close to a bean mill were affected by sudden asthma attacks. 

Allergic reactions are characterized by the production of allergen-specific IgE with a predominant Th2 response [25-26]. Helper T cells can be divided largely into two subgroups, Thl and Th2, on the basis of their cytokine production patterns. Thl cells, which produce IL-2 and IFNy, induce cell-mediated immunity characterized by macrophage activation and cytotoxic T lymphocyte (CTL) induction, while Th2 cells, which produce IL-4, IL-5, IL-6, and IL-10, help for antibody production. 

Nanoscale debris from CoCrMo, which is also a widely used orthopedic implant material, may also induce DNA and chromosome damage as well as cytotoxicity. For instance, CoCr nanoparticles demonstrated more severe DNA damage, chromosomal damage, and toxic effects compared to micron-sized CoCr particles [8,9]. For orthopedic implants made of stainless steels, Fe or Ni nanoparticles are also possible sources for triggering toxicity and adverse effects at local or systemic levels. For example, Ni particles implanted in rat soft tissues were found to cause just allergic reactions when... 

Azelaic acid is a non-phenoUc derivative (1,7-heptanedi-carboxyUc acid) acting as a weak tyrosinase inhibitor and producing antiproliferative and cytotoxic effects on abnormal melanocytes. It has anti-inflammatory, antibacterial, and anti-keratinizing activities. At 10-20% concentration, twice-daily application may treat melasma with minimal side effects (allergic reactions). Its efficacy is comparable if not better than HQ 2-4%,... 

Despite their anti-inflammatory and immunosuppressive properties, CSs can provoke both immunological and inflammatory responses, occasionally inducing immediate type 1 and delayed type IV allergic reactions. Type 11 cytotoxic and type III immune complex reactions do not appear to have been reported. 

Allergic reactions to aU three agents have been described. For etanercept, injection site reactions can occur in up to 20% of patients (287). Some patients develop recall reactions in areas of prior injections (288). More severe reactions, including anaphylactoid reactions, have been reported with infliximab. Up to 20% of patients with infliximab develop infusion reactions. The rate is lower for those patients receiving a concomitant cytotoxic drug such as MTX (289). Infliximab is a chimeric monoclonal antibody. Patients with infusion reactions to infliximab have been successfully treated with the humanized monoclonal antibody adalimumab (278,290). 

Because many of these allergic reactions are directed against invasive larvae and are accompanied by marked local tissue eosinophilia, such reactions may serve to kill or immobilize larvae. In such reactions, crosslinking of mast cell-bound IgE by parasite antigens may be important in local eosinophil recruitment. Additionally, coating of parasites by antibodies including IgE may be important in antibody-dependent cellular cytotoxicity (ADCC) by eosinophils (25). 

Compounds (I) through (IV) were assayed for their cytotoxic and allergenic potential on guinea pigs, which are effective indicators of contact allergenicity in humans (10). The same compounds were also tested on Tenebrlo sp. (mealworm beetles), an experimental Insect used to test the potential of insecticides. Geranyl-benzoquinone proved to be a very potent elicitor of allergic skin reactions as well as a potent insecticide (10). 

---