Induction of cytokine mRNAs in mice after oral exposure to the trichothecene vomitoxin (deoxynivalenol): relationship to toxin distribution and protein synthesis inhibition

The effects of oral exposure to 0, 5, and 25 mg/kg body wt vomitoxin (VT) on cytokine mRNA levels in spleen, Peyer's patches (PP), liver, kidney, and small intestine were evaluated in B6C3F1 mice at 2 and 4 hr postexposure using RT-PCR in conjunction with Southern hybridization analysis. The abundance of mRNAs for several cytokines was increased in VT-exposed mice with maximal effects occurring in the 25 mg/kg group at 2 hr. Specifically, IL-1 beta and IL-6 mRNA levels increased in spleen and PP following exposure to VT. TNF-alpha mRNA levels were markedly elevated in spleen and liver of VT-exposed mice. TGF-beta mRNA was increased in treatment kidneys and to a lesser extent in liver and small intestine. IFN-gamma mRNAs were elevated according to the rank order: spleen > PP > small intestine > liver > kidney, whereas IL-2 mRNAs were increased primarily in spleen and PP. VT had little effect on abundance of mRNAs for the TH2 cytokines, IL-4 and IL-5, or the housekeeping gene, hypoxanthine guanine ribosyl transferase. In order to relate cytokine mRNA abundance to toxin distribution, mice were administered 5 and 25 mg/kg VT body wt containing [3H]VT and tissue levels were monitored over time. Maximum VT molar equivalents for both doses were found at 30 min or 1 hr in all tissues with a rapid clearance following two-compartment kinetics over 24 hr. When effects of oral VT exposure on in vivo protein synthesis at 3 hr postexposure was measured using [14C]leucine uptake, it was found to be inhibited by > or = 20 and > or = 50% in tissues of mice receiving 5 and 25 mg/kg VT, respectively. While recovery was observed in tissues of the 5 mg/kg group at 6 hr, protein synthesis was still significantly inhibited (> or = 70%) at 9 hr for all tissues in the 25 mg/kg group. The results suggest that acute oral VT exposure resulted in the transient elevation of mRNAs for proinflammatory and TH1 cytokines. These effects occurred immediately after peak VT accumulation and concurrently with marked in vivo protein synthesis inhibition.

Canthin-6-one alkaloids from Brucea mollis var. tonkinensis

Three new alkaloids were isolated from the root-wood of Brucea mollis var. tonkinensis collected in China. Their structures were determined to be 11-O-beta-D-glucopyranosyl-(1-->6)-beta- D-glucopyranosylcanthin-6-one, 5-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosylcanthin-6-o ne and 11-hydroxycanthin-6-one-N-oxide, by chemical and spectral methods. In addition, two known alkaloids, canthin-6-one and canthin-6-one-N-oxide, were isolated.

Hepatic adenoma: report of three cases and review of the literature

Pathologically confirmed hepatic adenoma (HA) was observed in two women who were not using contraceptives and one 60-year-old man. All three cases had a mass in the right lobe of the liver and almost normal laboratory results. One case that had a movable pedunculated mass mimicked an extrahepatic tumor preoperatively, and two cases associated with acute abdominal pain resulting from intratumor hemorrhage were misdiagnosed as hepatoma and given interventional therapy prior to liver biopsy. In hepatic arterial DSA of two cases, the tumor appeared as hypervascular with peripheral blood supply and regularly parallel branches coursing centrally. On CT scans, the tumor appeared to be surrounded by a low-density ring in two cases, and an intratumor hyperdense area of fresh blood was noted in one case. Analysis of the three cases in this series and a review of the literature indicated that if the DSA and CT findings described above were revealed in a patient, particularly a young woman, with a mass of the right lobe of the liver (with or without acute abdominal pain) and normal laboratory results, HA should be strongly suspected, and CT-guided biopsy should be performed for pathological diagnosis, particularly when an equivocal diagnosis is made.

Distribution of ryanodine receptors in the chicken central nervous system

The ryanodine receptor (RR), an intracellular calcium release channel, has been identified in the nervous system but its contributions to neuronal function are unknown. We have utilized immunohistochemical techniques to establish the distribution of RRs in the central nervous system (CNS) of the chick as a step toward elucidating the function of RRs in this system. RR immunoreactivity is observed throughout the brain, most prominently in large neurons. The strongest immunoreactivity is found in cerebellar Purkinje neurons, but nuclei in the motor, visual and vestibular systems are also intensely labeled, and immunoreactive neurons are observed the olfactory bulb and the hippocampus. In these neurons, labeling is prominent in cell bodies, dendrites and axons, but is not observed in the dendritic spines or in plasma membranes. The neuronal RRs bind [3H]ryanodine with high affinity and this activity is regulated by calcium, caffeine, MgCl2/ATP and ionic strength. Multiple forms of the RRs are found in the chicken CNS. Immunoprecipitation and localization studies using RR isoform specific monoclonal antibodies reveal major differences in their distribution. The predominant species in the cerebellum is similar to the skeletal muscle isoform while there is a lower level of expression of either the cardiac or beta skeletal isoforms. In the remainder of the brain, the predominant isoform is similar to the cardiac or beta skeletal muscle isoforms. The broad distribution of RRs in the CNS suggests that calcium release events mediated by these proteins may have a functional role in a diverse array of neurons. Moreover within the populations of neurons expressing RR's, the presence of specific RR isoforms may correlate with specialization in the calcium release events mediated by these proteins.

Digital subtraction angiography in the diagnosis of congenital heart diseases: analysis of 60 cases

Ninety-one IVDSA and/or IADSA examinations with 192 injections were performed in 60 patients with congenital heart disease (CHD), including 31 anatomic anomalies. Axial projection was used in 23 patients. Analysis of the results of this series showed that accurate diagnosis by DSA confirmed by cardiac surgery together with definite diagnosis by DSA were obtained in 54 cases (90%). Two cases of nondiagnosis by DSA resulted from a suboptimal DSA method; four cases of partially accurate or mistaken diagnosis determined by cardiac surgery occurred because the axial view was not used and/or the anomalies were too small to be visualized by DSA. To increase the diagnostic accuracy of DSA in CHD, an optimal method of DSA must be selected according to the position of the anomaly and the hemodynamic data, and the axial view should be used to visualize the anomaly clearly in complex cases. In addition, DSA may fail to define a mild anomaly because of its lower spatial resolution.

VIRTUS, a model of virus transport in unsaturated soils

As a result of the recently proposed mandatory groundwater disinfection requirements to inactivate viruses in potable water supplies, there has been increasing interest in virus fate and transport in the subsurface. Several models have been developed to predict the fate of viruses in groundwater, but few include transport in the unsaturated zone and all require a constant virus inactivation rate. These are serious limitations in the models, as it has been well documented that considerable virus removal occurs in the unsaturated zone and that the inactivation rate of viruses is dependent on environmental conditions. The purpose of this research was to develop a predictive model of virus fate and transport in unsaturated soils that allows the virus inactivation rate to vary on the basis of changes in soil temperature. The model was developed on the basis of the law of mass conservation of a contaminant in porous media and couples the flows of water, viruses, and heat through the soil. Model predictions were compared with measured data of virus transport in laboratory column studies and, with the exception of one point, were within the 95% confidence limits of the measured concentrations. The model should be a useful tool for anyone wishing to estimate the number of viruses entering groundwater after traveling through the soil from a contamination source. In addition, model simulations were performed to identify parameters that have a large effect on the results. This information can be used to help design experiments so that important variables are measured accurately.

Nonmammalian vertebrate skeletal muscles express two triad junctional foot protein isoforms

Mammalian skeletal muscles express a single triad junctional foot protein, whereas avian muscles have two isoforms of this protein. We investigated whether either case is representative of muscles from other vertebrate classes. We identified two foot proteins in bullfrog and toadfish muscles on the basis of (a) copurification with [3H]epiryanodine binding; (b) similarity to avian muscle foot proteins in native and subunit molecular weights; (c) recognition by anti-foot protein antibodies. The bullfrog and toadfish proteins exist as homooligomers. The subunits of the bullfrog muscle foot protein isoforms are shown to be unique by peptide mapping. In addition, immunocytochemical localization established that the bullfrog muscle isoforms coexist in the same muscle cells. The isoforms in either bullfrog and chicken muscles have comparable [3H]epiryanodine binding capacities, whereas in toadfish muscle the isoforms differ in their levels of ligand binding. Additionally, chicken thigh and breast muscles differ in the relative amounts of the two isoforms they contain, the amounts being similar in breast muscle and markedly different in thigh muscle. In conclusion, in contrast to mammalian skeletal muscle, two foot protein isoforms are present in amphibian, avian, and piscine skeletal muscles. This may represent a general difference in the architecture and/or a functional specialization of the triad junction in mammalian and nonmammalian vertebrate muscles.

Identification and localization of ryanodine binding proteins in the avian central nervous system

Ryanodine binding proteins of the CNS have been identified using monoclonal antibodies against avian skeletal muscle ryanodine binding proteins. These proteins were localized to intracellular membranes of the dendrites, perikarya, and axons of cerebellar Purkinje neurons using laser confocal microscopy and immunoelectron microscopy. Ryanodine binding proteins were not found in dendritic spines. Immunoprecipitation and [3H]epiryanodine binding experiments revealed that the cerebellar ryanodine binding proteins have a native molecular weight of approximately 2000 kd and are composed of two high molecular weight (approximately 500 kd) polypeptide subunits. A comparable protein having a single high molecular weight polypeptide subunit was observed in the remainder of the brain. If the ryanodine binding proteins in muscle and nerve are similar in function, then the neuronal proteins may participate in the release of calcium from intracellular stores that are mechanistically and spatially distinct from those gated by inositol trisphosphate receptors.

Mechanism of action of colchicine. VI: Effect of colchicine on generation of leukotriene B4 by human polymorphonuclear leukocytes

Three microtubule-disruptive agents (colchicine, oncodazole, and vinblastine) are shown to suppress ionophore A23187-induced generation of LTB4 in a dose-related manner. The slopes of the dose-response regression lines were similar for the three drugs. Trimethyl-colchicinic acid has no effect on LTB4 generation. The suppressive effect of colchicine (1 x 10(-6) M) can be blocked completely by taxol (1 x 10(-6) M) which promotes and stabilizes microtubule assembly. The data suggest that colchicine suppresses the generation of LTB4 via its effect on microtubules.