The Preliminary Study on the Distribution of Halothane Gene in Breeding Pigs from Beijing Area

[Objective] The aim was to investigate the distribution of the halothane （Haln） gene in breeding pig group in Beijing area.[Method] PCR-RFLP method was used to determine Haln genotype of 609 breeding pigs from boar stations and pig breeding farms in Beijing.[Result] The Haln gene frequencies of Large White,Landrace,Duroc and Pietrain pigs of the boar stations were 0,17.11%,5.56% and 18.75%,respectively; and the Haln gene frequencies of Large White,Landrace and Duroc pigs of pig breeding farms were 4.52%,11.68% and 23.33%,respectively.[Conclusion] The result provided a basis for the rational use of Haln gene.

Ca^(2+) cytochemical changes of hepatotoxicity caused by halothane and sevoflurane in enzyme-induced hypoxic rats

AIM： To investigat the relation between hepatotoxicity of halothane and sevoflurane and altered hepatic calcium homeostasis in enzyme-induced hypoxic rats. METHODS： Forty-eight rats were pretreated with phenobarbital and randomly divided into six groups （eight in each group） and exposed to O2/N2/1.2 MAC anesthetics for 1 h： normal control （NC）, 21% O2/79% N2; hypoxic control （HC）, 14% O2/86% N2; normal sevoflurane （NS）, 21% O2/ N2/1.2MAC sevoflurane; hypoxic sevoflurane （HS）, 14% O2/N2/1.2MAC sevoflurane; normal halothane （NH）21%O2/79%N2/1.2MAC halothane; hypoxic halothane （HH）, 14%O2/N2/1.2MAC halothane. Liver specimens and blood were taken 24 h after exposure to calcium and determined by EDX microanalysis. RESULTS： The liver of all rats given halothane （14% O2） had extensive centrilobular necrosis and denaturation. Morphologic damage was accompanied with an increase in serum glutarnic pyruvic transminase. In groups NH and HH, more calcium was precipitated in cytoplasm and mitochondria. CONCLUSION： These results suggest that halothane increases cytosolic Ca^2＋ concentration in hepatocytes. Elevation in Ca^2＋ concentration is implicated in the mechanism of halothane-induced hepatotoxicity. sevoflurane is less effective in affecting hepatic calcium homeostasis than halothane.

Experimental research on phospholipids variation of halothane on liver mitochondria

AIM To study the pathogenesis of hepatotoxicity of halothane. METHODS The effect of different concentration of halothane and sevoflurane on mitochondrial membrane phospholipids composition of rat liver were analyzed using high performance liquid chromatography (HPLC) technology. RESULTS Halothane at low concentration could degrade mitochondrial membrane major phospholipids and increase lysophosphatidylcholine. CONCLUSION The pathogenesis of halothane hepatotoxicity was the phospholipids variation on liver mitochondria.

Halothane hepatitis in Iran:A review of 59 cases

AIM:To study halothane hepatitis (HH) in Iran and its associated risk factors. METHODS: We retrospectively studied files of all cases diagnosed with HH referred to three referral hospitals and four private centers in Iran from April 1994 to September 2006. Information on age at surgery, gender, medications history, obesity, history of previous exposure, previous reaction to halothane, familial history, type of surgery, perioperative hypoxia or sepsis, morbidity and mortality were recorded and analyzed. RESULTS: A total of 59 cases were identifi ed. Forty- eight (81%) were women. The median age at the time of surgery was 44 years (range, 18 to 80 years). Sixty percent of patients were above 40-year-old. Obesity was observed in 22.2%. Previous history of exposures to halothane was noted in 61% of which 50% had history of post-exposure reaction. Coronary artery bypass graft (CABG), cholecystectomy, and cosmetic surgeries (mainly weight reduction) were the most frequent surgeries. The mortality rate was 12.2%. In patients developing encephalopathy, it was as high as 50%. CONCLUSION: HH remains an important cause of morbidity and mortality in centers still using this anesthetic. However, a large percentage of these casescould have been avoided. To lessen occurrence of further cases of HH, the authors suggest that in female patients having a history of surgery (or delivery) with general anesthesia, the use of halothane should be absolutely avoided. Utilization of proper substitutes in adults’ anesthesia is advocated.

Expression and distribution of c-fos oncogene within central nervous system of the rat following halothane anesthesia

Objective: To study the distribution of c fos oncogene expression within central nervous system (CNS) of the rat during halothane anesthesia. Methods: c-fos oncogene immunohistochemical technique (ABC method) was employed. Results: When halothane concentration was 0.75%,1.5%or2.0%, most of the Fos-like immunore- active neurons (FLNs) appeared in telencephalon, diencephalon and brain stem, including cerebral cortex, amygaloid nucleus, accumbens nucleus, lateral keptal nucleus. bed nucleus of the stria terminalis, field CA1 of Ammon’s horn, islands of Calleja, paraventricular thalamic nucleus, central medial thalamic nucleus, reuniens thalamic nucleus, rhomboid thalamic nucleus. ventral posterolateral thalamic nucleus, paraventricular hypothalamic nucleus(ventral part). periventricular hypothalamic nucleus, median preoptic nucleus, supraoptic nucleus, suprachiasmatic nucleus. medial and lateral habenular nucleus. midbrain periaqueductal gray and Edinger-Westphal nucleus.In the present stude. we have also found that the number of FLN registered stable increase along with the increaseof the concentration of halothane. Conclusion: It has been indicated that FLNs participate in the process ofhalothane anesthesia. which should necessitate and pave the way for a further study of the patterns of linkage andthe mechanism of interaction between functional nuclei.

Low-dose Simvastatin Increases Skeletal Muscle Sensitivity to Caffeine and Halothane

Objective To determine whether the myotoxic side effects of statin simvastatin affect skeletal muscle's sensitivity to caffeine and halothane. Methods Primary cultured neonate rat skeletal myotubes were treated with 0.01-5.0 μmol/L simvastatin for 48 hours. MTT was used to evaluate cellular viability. The gross morphology and microstructure of the myotubes were observed with a light and electron microscope, respectively. The intracellular calcium concentrations([Ca^(2+)]i) at rest and in response to caffeine and halothane were investigated by fluorescence calcium imaging. Data were analyzed by analysis of variance(ANOVA) test. Results Simvastatin(0.01-5.0 μmol/L) decreased myotube viability, changed their morphological features and microstructure, and increased the resting [Ca^(2+)]i in a dose-dependent manner. Simvastatin did not change myotube's sensitivity to low doses of caffeine(0.625-2.5 mmol/L) or halothane(1.0-5.0 mmol/L). In response to high-dose caffeine(10.0 mmol/L, 20.0 mmol/L) and halothane(20.0 mmol/L, 40.0 mmol/L), myotubes treated with 0.01 μmol/L simvastatin showed a significant increase in sensitivity, but those treated with 1.0 μmol/L and 5.0 μmol/L simvastatin showed a significant decrease. The sarcoplasmic reticulum Ca^(2+) storage peaked in the myotubes treated with 0.01 μmol/L simvastatin, but it decreased when cells were treated with higher doses of simvastatin(0.1-5.0 μmol/L).Conclusions The myotoxic side effect of simvastatin was found to change the sensitivity of myotubes in response to high-dose caffeine and halothane. When dose was low, sensitivity increased mainly because of increased Ca^(2+) content in the sarcoplasmic reticulum, which might explain why some individuals with statin-induced myotoxic symptoms may show positive caffeine-halothane contracture test results. However, when the dose was high and the damage to the myotubes was severer, sensitivity was lower. It is here supposed that the damage itself might put individuals with statin-induced myotoxic symptoms at greater risks of presenting with rhabdomyolysis during surgery or while under anesthesia.

Role of cellular immunity in halothane hepatitis: an in vitro study

Objective: To explore the effect of cellular immunity in halothane hepatitis. Methods: Hepatotoxicity model was established by exposing male Hartley guinea pigs to 1% halothane via inspiration for 4 h each time for 1 or 3 times within a 42-day interval. Then their hepatocytes and lymphocytes were collected and divided into 2 parts for different cultures. Hepatocytes were cultivated with or without 1% halothane for 4 h and lymphocytes were cultivated with or without 12.5 μg/ml trifluoroacetylated guinea pig serum albumin (TFA-GSA). Then the 2 kinds of hepatocytes were co-cultivated with lymphocytes (1:100) with or without TFA-GSA induction respectively and the supernatant fluid was taken after 24, 48 and 72 h to determine the concentration of alanine aminotransferase (ALT). The halothane cultivated hepatocytes were co-cultivated with various proportion of TFA-GSA antigen induced lymphocytes and ALT was determined after 48 h to determine the proper proportion of hepatocytes and lymphocyte. Results: Lymphocytes of 3 times halothane induced guinea pigs caused a significant increase of ALT in hepatocytes with or without halothane induction. But the lymphocytes of 1 time halothane induced guinea pigs only caused a significant increase of ALT in hepatocytes with induction of halothane. The increase of ALT was only seen after 48- and 72-hour co-culture. The proper proportion of hepatocytes and lymphocytes was 1:100 for lymphocytes cytotoxicity. Conclusion: Lymphocytes is sensitized after inhalation of halothane and generates cytotoxicity to hepatocytes. The immune response of lymphocytes to hepatocytes will be enhanced by repeated inhalation of halothane. The cellular immunity may be one of the mechanisms of halothane induced hepatotoxicity.

Stereological and cytochemical study on the pathogenesis of hepatitis induced by halothane in rats

This study was designed to investigate the relationship between hepatotoxicity of halothane and altered hepatic calcium homeostasis in enzyme-induced hypoxic rats by means of Ca2+ cytochemical location and EDX microanalysis combined with stereology of liver and ultrastructural analysis by computer. It was found that more calcium precipitated in the cytoplasm and mitochondria of liver than that in the controls following halothane exposure. This alteration appears to be the result of accelerated uptake of Ca2+ by hepatocytes and decreased output of loaded Ca2+ on the one hand, and increased release of reserved Ca2+ on the other hand. These results suggest that change in cullular Ca2+ balance plays an important role in the mechanism of hepatotoxicity induced by halothane exposure.

Study on Relationship Between Halothane Gene and Behavioral Stereotypies in Pregnant Sows

A simple preparation using the ear tissue for PCR amplification was established for diagnosis of genotypes for halothane in 181 sows.3 halothane heterozygous pigs were detected.The behaviors of the sows that have different genotypes were observed.The heterozygous sows expressed seem more behavioral stereotypies than halothane resistant.But there is no difference in two genotypes.The behaviour directed trough in heterozygous sows is higher than halothane resistant.

Genetic Screening of Halothane Gene on Selected Philippine Native Pig Herds

The establishment of nucleus herds (NHs) of Native Pigs (NPs) at various R&D stations in the Philippines is currently being undertaken for food security and genetic conservation advocacy. Marker-assisted selection (MAS) is being utilized to identify individuals carrying favorable alleles of genes associated with production traits and screen out genetic defects (GD) for breeding purposes. Porcine Stress Syndrome (PSS) caused by a mutation in Halothane (HAL) gene is a GD frequently found in commercial breeds that when expressed, causes pale, soft, exudative (PSE) meat. PSE is inferior quality meat undesirable in the market causing economic losses to the swine industry. Thus, this study was conducted to screen the HAL gene through mutagenically separated-polymerase chain reaction (MSPCR) in selected NP herds and assessed its repeatability in local breeds. Results showed that out of 577 screened individuals, 543 (94.11%) were normal (NN), 0 (0%) were homozygous mutant (nn) and 34 (5.89%) were heterozygous carriers (Nn). Therefore, the optimized PSS screening protocol using MSPCR is also applicable to local breeds. As such, the availability of genetic tests for PSS could be useful in improving the Philippine NPs breeding selection and inhibiting or eliminating PSS mutant incidence within its nucleus herd.

A Mechanism for Inhaled Anesthetic-Induced Solid Organ Injury: Inflammation

Background: Inhaled anesthetics, including halothane, iso- and sevoflurane induce proinflammatory cytokine release. Halothane is an inhaled anesthetic agent that is metabolized by the liver into a highly reactive product, trifluoroacetyl chloride, which can react endogenously to form a trifluoroacetyl-adduct (TFA-adduct). The MAA-adduct is formed by acetaldehyde and malondialdehyde reacting with endogenousproteins and is found in both patients and animals post-consumption of alcohol. These TFA and MAA-adducts have been shown to cause the release of proinflammatorycytokines by endogenous inflammatory cells. If both adducts share a similar mechanism of cell activation, receiving general anesthesia following alcohol ingestion could exacerbate the inflammatory response caused by the inhaled general anesthetic halothane and lead to solid organ (including liver and brain) injury. Methods: Control diet and alcohol-fed rats were randomized to receive halothane pretreatments by intraperitoneal injection mixed in sesame oil. Following the intraperitoneal injections, the intact heart was removed, HECs were isolated and stimulated with unmodified bovine serum albumin (Alb), MAA-modified Alb (MAA-Alb), Hexyl-MAA, or lipopolysaccharide (LPS), and supernatant concentrations of TNF-α were determined. Results: Halothane pre-treated rat HECs demonstrated significantly greater TNF-α concentration following MAA-adduct and LPS stimulation than the non-halothane pre-treated in both pair and alcohol-fed rats, but was significantly greater in the alcohol-fed groups. Conclusion: These results demonstrate that halothane and MAA-adduct pre-treatment will increase the inflammatory response (TNF-α release) in rat HECs following LPS and MAA stimulation in vitro. Also, these results suggest that halothane exposure may increase the risk of alcohol-induced solid organ injury secondary to TNF-induced inflammation. Other investigators have reported similar proinflammatory cytokine release with other (isoflurane and sevoflurane) inhaled anesthetic exposure, suggesting that inhaled anesthetics should be used with caution in alcohol consuming humans.