Modulation of tricarboxylic acid cycle dehydrogenases during hepatocarcinogenesis induced by hexachlorocyclohexane in mice

The sequential distribution of key tricarboxylic acid (TCA) cycle enzymes have been investigated during hexachlorocyclohexane (HCH)-induced hepatocarcinogenesis in Swiss mice. Animals were continuously exposed to HCH (500 ppm) for 2, 4, and 6 months until liver tumor developed. The activity of TCA cycle enzymes such as isocitrate dehydrogenase (ICDH), succinate dehydrogenase (SDH), and malate dehydrogenase (MDH) have been studied. The activity of all the enzymes declined after 2 months of exposure of HCH in the liver. The neoplastic nodules and tumors developed after an exposure of HCH for 4 and 6 months, respectively. Neoplastic nodule and tumor showed wide variations in the activity and distribution of TCA cycle enzymes. The decreasing pattern in the activity of enzymes persisted in the non-neoplastic and non-tumor regions of the liver except SDH. However, the cells in nodular area and tumor showed intense enzymatic activities at cellular level. In the nodular region SDH activity declined prominently, whereas the non-nodular area showed positive reaction. Conspicuously, the tumor showed islands of positive and negative zones for TCA cycle dehydrogenases. The significance and relevance of such a distribution pattern still remains a mystery. The results are discussed in the light of HCH-induced toxicity on energy metabolism in exposed animals and possible role of such enzymes in the tumor formation.     

Dexmedetomidine used to provide hypotensive anesthesia during middle ear surgery

This study was carried out to assess the hypotensive effect of low dose dexmedetomidine (DEX) infusion during middle ear surgery. 42 ASA grades I and II patients of either sex aged 18–45 years undergoing elective middle ear surgery were randomly divided into two groups of 21 each. Group I received placebo bolus and infusion of saline at a rate similar to DEX in Group II. Group II received 10–15 min prior to induction of anesthesia 1 µg/kg IV bolus DEX diluted in 10 ml of normal saline over 10 min. Immediately thereafter an infusion of 0.4 µg/kg/hr of DEX commenced. Standard anesthetic technique was used. Halothane was titrated to achieve a mean arterial pressure 30% below the control value (value taken just after premedication). We observed that a statistically significant reduction in the percentage of halothane required to reduce MAP 30% below control value occurred in patients receiving DEX infusion (1.3 ± 0.4%) in comparison to those receiving placebo (3.1 ± 0.3%). Patients receiving DEX infusion had a better surgical field. The mean awakening time was significantly reduced in patients of Group II (9.1 ± 2.7 min) when compared to patients of Group I (12.8 ± 2.2 min). We conclude that DEX can be safely used to provide hypotensive anesthesia during middle ear surgery.     

Prevalence,disease associations and risk factors for colonization with intestinal spirochaetes (Brachyspira spp.) in flocks of laying hens in north-eastern Italy

The present study investigated the occurrence of anaerobic intestinal spirochaetes of the genus Brachyspira in laying hen flocks in Treviso province, north-eastern Italy, with respect to prevalence, spirochaete species present, disease associations and risk factors for colonization. A total of 450 faecal samples from 45 sheds on 29 laying hen farms were cultured for intestinal spirochaetes. Nineteen sheds on 12 farms contained chickens with symptoms consistent with avian intestinal spirochaetosis, including reduced egg production, wet litter and/or pasty vents. Spirochaetes were isolated from 157 (34.8%) samples from 21 (72.4%) farms, and from 32 (71.1%) sheds. From these positive samples, 189 spirochaetal isolates were speciated using three polymerase chain reaction assays and a restriction fragment polymorphism analysis of 16S rDNA polymerase chain reaction products. Overall, 52 (27.5%) isolates were identified as pathogenic Brachyspira intermedia, 26 (13.8%) as pathogenic Brachyspira pilosicoli, 93 (49.7%) as non-pathogenic (Brachyspira innocens/Brachyspira murdochii), and 18 (9.6%) were unidentified. Faeces from 14 sheds (31%) on 10 farms (34.5%) contained B. intermedia and/or B. pilosicoli, and disease consistent with avian intestinal spirochaetosis was observed in nine of these sheds on seven farms. There was a significant association (P=0.042) between the presence of spirochaetes and using deep pits rather than conveyor belts for manure disposal. Sheds housing chickens >40 weeks of age were significantly more likely to contain spirochaetes (P=0.048) and pathogenic species (P=007) than sheds housing younger chickens. A significant association (P=0.02) was found between infection with pathogenic spirochaetes and reduced egg production.