Hyperthermia

Magnetic particles generate heat under AC magnetic fields due to the magnetic losses that arise from the various processes of magnetization reversal (i) hysteresis  

The energy absorbed by the magnetic particles under an applied external AC magnetic field is described by the specific absorption rate [SAR the term specific loss power (SEP) may also be used in some cases]. The SAR can be determined as  

00089 kg s applied AC magnetic field 40 Oe, and frequency 600 KHz. Reproduced with permission from Ref. [286] 2009, Elsevier. 

When the applied magnetic field is smaller than the saturation magnetization, within the validity of linear response theory (i.e., magnetization depends linearly on the applied magnetic field), the SAR can be determined as the loss power density P( f,H) normalized by the mass density of the particles (Wm ), expressed as  

The maximum SAR calculated for pure Fe- and Co-based systems can be significantly higher compared to iron oxide nanopartides [204, 284, 285]. However, the main concern for use for in vivo applications is their potential toxicity assodated with the release of cytotoxic Co ions. 

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Intracerebroventricular injection of sulfolane in dosages of 300, 1000, and 3000 p.g caused the preoptic/anterior hypothalamic area temperature to rise 0.23, 0.47, and 0.56%, respectively. This hyperthermia was considered significant at the 3000-p.g dosage (30). 

Adverse effects with atropine therapy include dry mouth, myosis, loss of visual accommodations, constipation, and urinary retention. The dmg can also produce flushing, hyperthermia, delirium, tachycardia, and exacerbate glaucoma (85). 

In addition to direct effects of chemical compounds on the fetus, metabolic disturbances in the mother, such as diabetes or hyperthermia, or deficiencies of calories or specific nutrients such as vitamin A, zinc, and folic acid may lead to teratogenesis. Compounds that inhibit placental functions may also induce malformations, e.g., by inhibiting placental circulation. For example, hydroxyurea disrupts the placental circulation and induces malformations. In addition, it also induces DNA damage. 

Folic acid deficiency Hyperthermia Phenylketonuria Rheumatic disease Virilizing tumors Drugs and chemicals Androgenic chemicals Angiotensin-converting enzyme inhibitors Captopril, enalapril Antibiotics... 

Edwards, M. J. (1986). Hyperthermia as a teratogen A review of experimental. studies. and their clinical significance. Teratog. Carcinog. Mutag. 6, 56.3-S82. 

Following the action of extraordinary stimulants (hypoxic hypoxia, hypoxia + hyperoxia, hypodynamia + hyperthermia), animals demonstrate an accumulation of malonic dialdehyde with a simultaneous fall of antiradical activity of the liver tissue. A preliminary introduction to rats of acetylene amine 3,4,5-tris(morpho-linopropynyl)-l-methylpyrazole 103 and also of tocopherol antioxidant and gutumine antihypoxant averts activation of the lipid peroxidation processes. The inhibition of peroxidation with this agent is mediated by stabilization of ly-zosomal and mitochondrial membranes. Unsaturated amines prevent destruction of the organelle membranes provoked by UV irradiation and incubation at 37°C (pH4.7)(78MIl). 

Roth J, Rummel C, Barth SW et al (2006) Molecular aspects of fever and hyperthermia. Neurol Clin 24 421-439... 

Malignant hyperthermia (MH) is an autosomal-dominant pharmacogenetic disorder that is triggered by exposure to inhalation of general anesthetics, such as halothane. In susceptible individuals, these drugs can induce tachycardia, a greatly increased body metabolism, muscle contracture and an elevated body temperature (above 40°C) with a rapid rate of increase. Many cases of MH are linked to a gene for type 1 ryanodine receptor (RyRl). 

Neuroleptic-like malignant syndrome is a serious but very rare adverse effect of some drugs, of e.g., neuroleptics, some anaesthetics and apparently tolca-pone. Symptoms include hyperthermia, muscle deterioration, even dissolution. 

MDMA overdose as well as the concomitant consumption of selective serotonin reuptake inhibitors (SSRI) with other dmgs that exert serotoninergic effects (such as inhibitors of monoamine oxidase) can rapidly lead to the serotonin syndrome. Its symptoms, which are reversible upon cessation, of the drug include confusion, muscle rigidity in the lower limbs, and hyperthermia suggesting an acute reaction to serotonin overflow in the CNS. Blocking the function of SERT outside the brain causes side effects (e.g., nausea), which may be due to elevated 5HT however , impairment of transporter function is not equivalent to direct activation of 5HT recqrtors in causing adverse effects such as fibrosis and pulmonary hypertension. 

Robinson R, Carpenter D, Shaw MA et al (2006) Mutations in RYR1 in malignant hyperthermia and central core disease. Hum Mutat 27 977-989... 

HYPERTHERMIA. The nurse monitors the temperature at frequent intervals, usually every 4 hours unless the patient has an elevated temperature. When the patient has an elevated temperature the nurse checks the temperature, pulse, and respirations every hour until the temperature returns to normal and administers an antipyretic if prescribed by the primary care provider. 

The nurse monitors the patient for signs and symptoms of acute salicylate toxicity or salicylism (see Display 17-1). Initial treatment includes induction of emesis or gastric lavage to remove any unabsorbed drug from the stomach. Activated charcoal diminishes salicylate absorption if given within 2 hours of ingestion. Further therapy is supportive (reduce hyperthermia and treat severe convulsions with diazepam). Hemodialysis is effective in removing Hie salicylate but is used only in patients with severe salicylism. 

Transmission is autosomal dominant, and the relevant gene has been mapped to the same locus on chromosome 19q as that associated with susceptibility to malignant hyperthermia (pages 318-319). It is not established that the conditions are allelic. Almost all patients with CCD whose muscle has been tested in vitro for... 

Malignant hyperthermia may occur outside the operating room. Gronert has described a patient who had episodic fever and a positive muscle biopsy for MH. MH may occur in the postoperative recovery room or even on return to the ward. 

Table 1. Associated Musculoskeletal Disorders in Patients Susceptible to Malignant Hyperthermia...

Table 2. Conditions That May Initially Resemble Malignant Hyperthermia...

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