Isolation and Characterization of a Fast-Growing, Thermophilic Methanobacterium Species

A thermophilic, autotrophic methanogen (strain CB12, DSM 3664) was isolated from a mesophilic biogas digestor. This bacterium used H 2 -CO 2 or formate as a substrate and grew as short rods, sometimes in pairs and in crooked filaments. Motility was not observed. Its optimum temperature (56°C) was lower than that of other thermophilic members of the genus Methanobacterium . The maximum observed specific growth rate was 0.564 h −1 (74-min doubling time).

[Value and factors of influence in the combined method of the urine-purple-heat tolerance test in the diagnosis of cancer]

A method combining the urine cancer reaction, purple reaction and heat tolerance test (combined method of urine-purple-heat tolerance) was used to examine 112 normal persons, 110 non-cancer patients and 93 cancer patients. It was found that the accuracy rate of the urine reaction was 82%, of the purple reaction 77.4%, and of the heat tolerance 79%. The combined method showed great diagnostic value for cancers in the digestive tract, such as stomach, biliary duct, colon, pancreas and liver, as well as other cancers, e.g., lung cancer, lymphosarcoma and brain tumor. This method may be best for screening the above tumors. Its positive rate was also high in malignant reticuloma, chronic granulocytic leukemia and reticulosarcoma. The mechanism of the combined method and the influential factors, such as the freshness of the specimen, reactive time, temperature and quality of the reagents are discussed.

Responses of recurrent laryngeal motoneurons to changes of pulmonary afferent inputs

In decerebrate, paralyzed cats ventilated with a cycle-triggered pump, the discharges of the recurrent laryngeal (whole nerve or single fibers) and phrenic nerves, and the changes produced by pulmonary afferent inputs (lung inflation), were compared. When lung inflation was in phase with neural inspiration, four types of laryngeal fiber activities were observed: (a) phasic-inspiratory; (b) tonic-inspiratory; (c) expiratory-inspiratory; (d) early-expiratory. The firing patterns during inspiration were plateau-like, whereas the phrenic pattern was augmenting. When inflation was withheld, the plateau patterns usually became augmenting, indicating inhibition of laryngeal inspiratory activity by pulmonary afferents. Secondary effects of withholding inflation were (a) increases of early-expiratory activity (both whole nerve and individual fiber), indicating increased post-inhibitory rebound excitation; (b) decreased activity of tonic-inspiratory and expiratory-inspiratory fibers during early neural expiration, indicating increased inhibition by early-expiratory neurons. The discharge patterns of different types of laryngeal motoneuron, as well as their changes with inflation, are interpreted in relation to the function of regulating airway resistance.

Responses of early and late onset phrenic motoneurons to lung inflation

In anesthetized or decerebrate cats that were paralyzed and ventilated with a cycle-triggered pump, we produced changes in activity of the whole phrenic nerve and of individual phrenic motoneurons (fibers or cells in the spinal cord) by withholding lung inflation during the inspiratory (I) phase. The neurons were classified into early- and late-onset types (discharge onset less or greater than 80 msec, respectively, after whole phrenic onset). Both unit and whole phrenic activity exhibited a variety of responses to inflation (excitation, depression, or no effect); but there were no consistent differences between responses of early- and late-onset neurons. The distribution of responses was quite different from that of dorsal respiratory group (DRG) I neurons (Cohen and Feldman, 1984); in particular there was no group of phrenic neurons corresponding to the late-onset I-beta neurons (I neurons excited by inflation). We conclude that the inputs to late-onset phrenic neurons are not predominantly or exclusively from late-onset DRG neurons.

Hypoglossal motoneuron responses to pulmonary and superior laryngeal afferent inputs

In decerebrate, paralyzed cats ventilated with a cycle-triggered pump, the inspiratory discharges of the hypoglossal (whole nerve or single fibers), phrenic, and recurrent laryngeal nerves were compared, and the effects of pulmonary and superior laryngeal afferent inputs were observed. During lung inflations in phase with neural inspiration, hypoglossal and recurrent laryngeal activities differed from phrenic with respect to (a) burst onset times: both preceded the phrenic; (b) overall pattern: phrenic, augmenting; hypoglossal, decrementing; recurrent laryngeal, plateau-like. When inflation was withheld, the phrenic pattern was not markedly changed, but both hypoglossal and recurrent laryngeal became augmenting; the marked increase of hypoglossal activity (both whole nerve and single fiber) indicated strong inhibition by lung afferents. Superior laryngeal electrical stimulation evoked excitation of the contralateral phrenic (latency 4.1 msec) and the ipsilateral whole hypoglossal (latency 5.3 msec), followed by bilateral inhibitions (durations 20-30 msec); most hypoglossal fibers showed only inhibition. We conclude that, although both hypoglossal and phrenic outputs are driven by the inspiratory pattern generator(s), their promotor systems differ with respect to influences from central and peripheral inputs.

Fatty acid metabolism and cell proliferation. V. Evaluation of pathways for the generation of lipid peroxides

Primary cultures of smooth muscle cells were established from the medial layer of guinea pig aorta. Confluent cells at passage level 4-6 were challenged with arachidonic acid and treated with a number of antioxidants and inhibitors of specific lipid peroxidation pathways. Lipid peroxidation was measured by the thiobarbituric acid test for malondialdehyde (MDA) and the isolation of hydroperoxy fatty acids (HPETE) by high performance liquid chromatography (HPLC). Prostanoids were measured by radioimmunoassay and the separation of labeled compounds by HPLC. MDA, 6-keto-PGF1 alpha, and PGE2 were formed when cells were challenged with arachidonic acid and these cells synthesized small amounts of one HPETE isomer, 15-HPETE. The HPETE isomers characteristic of the lipoxygenase pathway, 12-HPETE and 5-HPETE, were not detected. Furthermore, the lipoxygenase inhibitors, eicosatetraynoic acid (ETYA) and 6,7-dihydroxycoumarin (Esculetin), did not block MDA formation. These data show that MDA is not generated in the cells by a lipoxygenase pathway. The cyclooxygenase inhibitors, indomethacin and ETYA, did not block MDA formation but these agents blocked the formation of 15-HPETE. These data show both that 15-HPETE is generated by a cooxidation pathway and that 15-HPETE and cooxidation are not involved in MDA formation. Three inhibitors of cytochrome P450 linked lipid peroxidation, 2-amino-3-ethoxycarbonyl-6-benzyl-4, 5,6,7-tetrahydrothieno-[2,3-C]-pyridine (Tinoridine), 3-methyl-1,2-di-3-pyridyl-1-propanone (Metyrapone) and phenobarbital, did not block MDA formation. These data support earlier studies that indicated that MDA is not generated by a P450 pathway. Cells contained a bound precursor that decomposed to MDA when cells were treated with Fe3+. The cells exhibited autofluorescence and concentric lamellae in lipid droplets that are characteristic of ceroid-lipofuscin. These observations are consistent with lipid peroxidation through increased peroxisomal activity leading to the generation of MDA and the accumulation of ceroid-lipofuscin. The natural antioxidants, vitamin E and vitamin E quinone (EQ), and the synthetic antioxidants, butylated hydroxytoluene and nordihydroguaiaretic acid (NDGA), alpha-naphthol (alpha-N) and propyl gallate (PrGa), all blocked MDA formation in confluent smooth muscle cells, showing that these antioxidants did not function solely as specific inhibitors of lipoxygenase, cooxidation or P450 pathways. Cell proliferation was measured in cells challenged with arachidonic acid and treated with antioxidants and other inhibitors. The least cytotoxic and most potent antioxidant, EQ, blocked MDA formation in confluent cells and promoted grow