Effects of duration of isoflurane anesthesia and mode of ventilation on intracranial and cerebral perfusion pressures in horses

OBJECTIVE: To test the hypothesis that isoflurane-anesthetized horses during controlled ventilation and spontaneous ventilation exhibit temporal changes in cerebral hemodynamics, as measured by intracranial pressure and cerebral perfusion pressure, that reflect temporal changes in systemic arterial pressure. ANIMALS: 6 healthy adult horses. PROCEDURE: Horses were anesthetized in left lateral recumbency with 1.57% isoflurane in O2 for 5 hours in 2 experiments by use of either controlled ventilation (with normocapnia) or spontaneous ventilation (with hypercapnia) in a randomized crossover design. Intracranial pressure was measured with a subarachnoid strain-gauge transducer. Carotid artery pressure, central venous pressure, airway pressures, blood gases, and minute ventilation also were measured. RESULTS: Intracranial pressure during controlled ventilation significantly increased during constant dose isoflurane anesthesia and thus contributed to decreasing cerebral perfusion pressure. Intracranial pressure was initially higher during spontaneous ventilation than during controlled ventilation, but this difference disappeared over time; no significant differences in cerebral perfusion pressures were observed between horses that had spontaneous or controlled ventilation. CONCLUSIONS AND CLINICAL RELEVANCE: Cerebral hemodynamics and their association with ventilation mode are altered over time in isoflurane-anesthetized horses and could contribute to decreased cerebral perfusion during prolonged anesthesia.     

Growth of Glucose-uptake-deficient Mutant of Xanthomonas oryzae pv. oryzae in Rice Leaves

We isolated Xanthomonas oryzae pv. oryzae mutants deficient in the phosphoenolpyruvate : carbohydrate phos-photransferase system, a major glucose transport system in bacteria, using the glucose analogue 3-deoxy-3-fluoro-d-glucose (3FG). Glucose uptake by the mutants was decreased to 15–35% of the parental strain, and growth greatly decreased in synthetic media containing glucose as a sole sugar source. Growth of the mutants in rice leaves was, however, similar to the wild type. These findings suggest that glucose is not necessarily a major carbohydrate source for X. o. pv. oryzae in rice leaves. Received 11 August 2000/ Accepted in revised form 15 December 2000     

New method to evaluate water-soluble antioxidant activity based on protein structural change

A simple method to evaluate antioxidant activities of water-soluble ingredients of foods has been developed. Protective effects of antioxidants against hypochlorite radical or hydroxyl radical have been studied by comparing changes in absorbance of myoglobin (a standard reference) at 409 nm. Protective ratio, defined by absorbance changes of myoglobin with or without the antioxidant, was a good indicator to quantitatively evaluate the antioxidant activity against the hypochlorite radical or the hydroxyl radical, respectively. Radar charts indicating the antioxidant activities against DPPH (1,1-diphenyl-2-picrylhydrazyl), hypochlorite radical, and hydroxyl radical clearly differentiated the characteristics of five antioxidants including carnosine, glutathione, and vitamin C. By comparison of the radar charts, antioxidant activity of bonito meat hydrolysate was found to have similar characteristics to that of carnosine. The simple method proposed in this study would be useful for evaluating and characterizing the activities of water-soluble antioxidants contained in various food materials.     

Identification and some properties of anthocyanin isolated from Zuiki, stalk of Colocasia esculenta

Zuiki, a stalk of taro (Colocasia esculenta), is a traditional vegetable in Japan. Raw zuiki is often boiled and vinegared to eat. The surface color of zuiki is reddish. Here, we isolated a red pigment from zuiki and identified it as cyanidin 3-rutinoside using instrumental analyses. The color of zuiki disappeared by boiling, but the zuiki turned red again in an acetic acid solution. It seems that the cyanidin 3-rutinoside that exists on the surface of zuiki elutes in boiling water and then, the pigment that seeps out from the inside of the zuiki is exposed to an acid solution, and its surface turns red again. The radical scavenging activity of purified zuiki anthocyanin was 114 mg equivalent to BHT/g. About half of the anthocyanin in fresh zuiki was washed out by boiling, and the radical scavenging activity of zuiki was definitely reduced.     

Simultaneous identification of species and trichothecene chemotypes of <Emphasis Type="Italic">Fusarium asiaticum</Emphasis> and <Emphasis Type="Italic">F. graminearum</Emphasis> sensu stricto by multiplex PCR

A multiplex PCR assay was developed for simultaneous identification of the species and trichothecene chemotypes for Fusarium asiaticum and F. graminearum sensu stricto based on the genes related to trichothecene biosynthesis. PCR was carried out in a single reaction with three pairs of primers designed for the tri6 region and one pair of primers designed for tri3. We confirmed that the multiplex PCR was able to identify species and chemotypes for all tested strains of F. asiaticum and F. graminearum s. str. isolated in Japan. This technique would be a useful and rapid tool for diagnosis, epidemiology, and population structure studies of the F. graminearum complex in Japan.     

Regulatory network of hrp gene expression in Xanthomonas oryzae pv. oryzae

Like other plant-pathogenic bacteria, Xanthomonas oryzae pv. oryzae, the causal agent of bacterial leaf blight of rice, has hrp genes that are indispensable for its virulence. The hrp genes are involved in the construction of the type III secretion (T3S) apparatus, through which dozens of virulence-related proteins, called effectors, are directly secreted into plant cells to suppress and disturb plant immune systems and/or induce plant susceptibility genes. The expression of hrp genes is strictly regulated and induced only in plants and in certain nutrient-poor media. Two proteins, HrpG and HrpX, are known as key regulators for hrp gene expression. Great efforts by many researchers have revealed unexpectedly that, besides HrpG and HrpX, many regulators are involved in this regulation, some of which also regulate the expression of virulence-related genes other than hrp. Moreover, it has been found that HrpG and HrpX regulate not only hrp genes and effector genes but also genes unrelated to the T3S system. These findings suggest that the expression of the hrp gene is orchestrally regulated with other virulence-related genes by a complicated, sophisticated regulatory network in X. oryzae pv. oryzae.