Linearity of the accumulation of various dosages of uranium in the major organs of mature male Japanese quail. Effect of various doses of estradiol-17 beta

1. Male Japanese quail were given 2.20 x 10(-4)-14.53 mg uranium/kg intravenously as uranyl ion (235U label). 2. The relationship between dosage and the 18-hr accumulation of U in leg bones, liver, kidneys and testes was linear. 3. Increases in U deposition with increased dosage were approximately 1:1, except for kidneys where 10-fold increases in dosage resulted in 25-fold increases in deposition. 4. Estradiol-17 beta increased U deposition in bones by 15-fold thereby providing some protection for the kidneys as now the ratio of dosage to accumulation was 1:1.     

Concentrations of glandular kallikrein in human nasal secretions increase during experimentally induced allergic rhinitis

We have previously demonstrated that a mixture of bradykinin and lysylbradykinin is generated in nasal secretions during the immediate allergic response to allergen. The present studies were performed to determine whether glandular kallikrein plays a role in kinin formation during the allergic reaction. Allergic individuals (n = 7) and nonallergic controls (n = 7) were challenged intranasally with appropriate allergen, and nasal lavages obtained before and after challenge were assayed for immunoreactive glandular kallikrein as well as for histamine, kinins, and N-alpha-tosyl-L-arginine methyl esterase (TAME-esterase) activity. The increase in postchallenge immunoreactive glandular kallikrein levels above baseline was significantly greater (p less than 0.01) for the allergic group (16.3 +/- 14 ng/ml; means +/- SD) than for the nonallergic controls (1.0 +/- 1.9 ng/ml). Increased levels of immunoreactive glandular kallikrein correlated with increases in kinins, histamine, and TAME-esterase activity and with the onset of clinical symptoms. Characterization of immunoreactive glandular kallikrein purified from postchallenge lavages by immunoaffinity chromatography confirmed the identity of this material as an authentic glandular kallikrein on the basis of its inhibition by protease inhibitors and by monospecific antibody to tissue kallikrein, its chromatographic behavior on gel filtration, and its ability to generate lysylbradykinin from highly purified human low m.w. kininogen. The specific activity of this purified material, in terms of kinin generation from kininogen, was very similar to that for authentic glandular kallikrein, suggesting that most if not all of the immunoreactive material purified from nasal lavages represented active enzyme. Inhibition studies by using pooled postchallenge lavages suggest that the majority of the kinin generating activity in these samples was due to glandular kallikrein. We conclude, therefore, that glandular kallikrein is secreted during the allergic response and can contribute to the formation of the lysylbradykinin produced during the allergic reaction.     

Differential enhancement of spontaneous transition mutations in the lacI gene of an Ung- strain of Escherichia coli

In this communication, the contribution of cytosine deamination to spontaneous mutagenesis in the lacI gene of E. coli was examined. In a wild-type strain, 75% of the amber mutations recovered were G:C----A:T transitions and 60% of these were at the 5-methylcytosine spontaneous hotspots Am6, Am15 and Am34. In a strain deficient for uracil-DNA glycosylase (Ung-), 96% of the amber mutations were G:C----A:T transitions while only 15% of these occurred at the hotspot sites. This shift in the mutational distribution demonstrates that cytosine deamination is a potent mutagenic process, which is enhanced in the absence of glycosylase. Moreover, some amber sites were greatly enhanced in the Ung- strain while others were only slightly enhanced. This result suggests that the rate of cytosine deamination at individual sites may be influenced by surrounding base composition. Therefore, we examined the neighboring sequences and found a strong correlation between the fold-increase in mutation and the A/T richness of the surrounding sequence. It is suggested that A/T-rich regions denature more often, forming transient single strands in which cytosine residues would be expected to deaminate more readily.     

Mechanism of differences in pathogenicity between two variants of a laboratory strain of herpes simplex virus type 1

The mechanisms responsible for the difference in neurovirulence to inbred mice between two variants of the Miyama strain of herpes simplex virus type 1 (HSV-1) were studied. After intraperitoneal (i.p.) inoculation, the +GC (LPV) variant reached the spinal cord and the brain, and caused death. Conversely, the -GCr variant lacked the ability to gain access to the central nervous system (CNS) after the same route of infection and failed to kill susceptible mice. The initial virus growth after i.p. inoculation, as indicated by the number of infective centers (ICs) produced by the peritoneal exudate cells (PECs), was compared between these two variants. The virulent +GC (LPV) strain induced much more ICs than the attenuated -GCr variant. When the attenuated variant was preinoculated i.p. 24 hr before the challenge inoculation with the virulent variant by the same route, the production of ICs by the pathogenic variant was highly inhibited, and growth of this variant did not occur in the CNS. Thus, mice were protected from lethal infection by the virulent variant by preinoculation with the attenuated one. Moreover, the ability of mice to resist i.p. infection by HSV-1 was shown to be age-dependent.     

Phosphorylation of AMP by inorganic phosphorylating agents

AMP was phosphorylated by inorganic phosphorylating agents: cyclo-triphosphate and diphosphonate, in aqueous solution (70-80 degrees C, pH 6-12). The molecular structures of phosphorylated products were established by use of phosphorus-31 NMR and high-performance liquid chromatography (HPLC). The OH groups on AMP were phosphorylated by both phosphorylating agents to form 2'- or 3'-phosphate but an OH group on dAMP was not phosphorylated. Phosphorylation of OH group proceeds in two steps: formation of hydrogen bond between OH group and phosphorylating agent; subsequent nucleophilic attack of OH group on a phosphorus atom. Phosphate group on AMP was phosphorylated by diphosphonate but not by cyclo-triphosphate. The difference in the reactivities is explained in terms of charge repulsion between AMP and agents.     

Intracellular mitochondrial membrane potential as an indicator of hepatocyte energy metabolism: further evidence for thermodynamic control of metabolism

The lipophilic triphenylmethylphosphonium cation (TPMP+) has been employed to measure delta psi m, the electrical potential across the inner membrane of the mitochondria of intact hepatocytes. The present studies have examined the validity of this technique in hepatocytes exposed to graded concentrations of inhibitors of mitochondrial energy transduction. Under these conditions, TPMP+ uptake allows a reliable measure of delta psi m in intracellular mitochondria, provided that the ratio [TPMP+]i/[TPMP+]e is greater than 50:1 and that at the end of the incubation more than 80% of the hepatocytes exclude Trypan blue. Hepatocytes, staining with Trypan blue, incubated in the presence of Ca2+, do not concentrate TPMP+. The relationships between delta psi m and two other indicators of cellular energy state, delta GPc and Eh, or between delta psi m and J0, were examined in hepatocytes from fasted rats by titration with graded concentrations of inhibitors of mitochondrial energy transduction. Linear relationships were generally observed between delta psi m and delta GPc, Eh or J0 over the delta psi m range of 120-160 mV, except in the presence of carboxyatractyloside or oligomycin, where delta psi m remained constant. Both the magnitude and the direction of the slope of the observed relationships depended upon the nature of the inhibitor. Hepatocytes from fasted rats synthesized glucose from lactate or fructose, and urea from ammonia, at rates which were generally linear functions of the magnitude of delta psi m, except in the presence of oligomycin or carboxyatractyloside. Linear relationships were also observed between delta psi m and the rate of formation of lactate in cells incubated with fructose and in hepatocytes from fed rats. The linear property of these force-flow relationships is taken as evidence for the operation of thermodynamic regulatory mechanisms within hepatocytes.     

Histoenzymological and biochemical changes in the liver of adult female rats and of youngs born from Madiol-treated pregnant rats

The effect of a 30-day treatment with Madiol was studied on the activity of some enzymes, nucleic acids, protein and glycogen content of the liver of adult female rats and youngs born from mothers treated during pregnancy. Madiol caused a significant increase in SDH and Atp-ase activity, and decreased glycogen and acid phosphatase.     

Involvement of Kv1.3 and p38 MAPK signaling in HIV-1 glycoprotein 120-induced microglia neurotoxicity

Inflammatory responses mediated by activated microglia play a pivotal role in the pathogenesis of human immunodeficiency virus type 1 (HIV-1)-associated neurocognitive disorders. Studies on identification of specific targets to control microglia activation and resultant neurotoxic activity are imperative. Increasing evidence indicate that voltage-gated K⁺ (K_v) channels are involved in the regulation of microglia functionality. In this study, we investigated K_v1.3 channels in the regulation of neurotoxic activity mediated by HIV-1 glycoprotein 120 (gp120)-stimulated rat microglia. Our results showed treatment of microglia with gp120 increased the expression levels of K_v1.3 mRNA and protein. In parallel, whole-cell patch-clamp studies revealed that gp120 enhanced microglia K_v1.3 current, which was blocked by margatoxin, a K_v1.3 blocker. The association of gp120 enhancement of K_v1.3 current with microglia neurotoxicity was demonstrated by experimental results that blocking microglia K_v1.3 attenuated gp120-associated microglia production of neurotoxins and neurotoxicity. Knockdown of K_v1.3 gene by transfection of microglia with K_v1.3-siRNA abrogated gp120-associated microglia neurotoxic activity. Further investigation unraveled an involvement of p38 MAPK in gp120 enhancement of microglia K_v1.3 expression and resultant neurotoxic activity. These results suggest not only a role K_v1.3 may have in gp120-associated microglia neurotoxic activity, but also a potential target for the development of therapeutic strategies.     

Anaerobic ureolytic bacteria from caecal content and soft faeces of rabbit

Forty strains of ureolytic bacteria were isolated from the caecal content and soft faeces of seven rabbits by the anaerobic roll tube method and were characterized. The isolates were identified with Clostridium coccoides, Cl. innocuum, Peptostreptococcus productus, P. micros, Peptococcus magnus, Fusobacterium russii and Fusobacterium sp. Urease activity of representative strains of the various species was also determined. The study indicated that strongly-ureolytic anaerobic bacteria are present in the caecum of the rabbit.