Bacteriophage phi 6 envelope elucidated by chemical cross-linking, immunodetection, and cryoelectron microscopy.

Bacteriophage phi 6 is an enveloped dsRNA virus which infects the plant pathogenic Pseudomonas syringae bacterium. Using low dose cryoelectron microscopy we show that the nucleocapsid, spikeless virion, and intact virion have radii of 29, 35, and 43 nm, respectively. Thus, the membrane is 6 nm thick and the surface spikes of the receptor binding protein P3 extend 8 nm from the membrane surface. Cross-linking, immunological, and complementation evidence suggest that the spikes are formed of multimeric P3 molecules and that P3 is associated with membrane-bound protein P6. We observe that the envelope can accommodate up to 400 molecules of P3 but that the average virion contains less than one-fourth of this amount. Assembly of a very small number of P3 or truncated P3 molecules onto inactive virions restores infectivity, showing that only a few spikes are necessary for receptor binding and membrane fusion.     

Verapamil-induced gingival overgrowth: a clinical, histologic, and biochemic approach

Verapamil-induced overgrowth was most prominent in the anterior regions and interproximal areas associated with plaque retention. Despite periodontal therapy, overgrowths recurred 1 month after gingivectomy. Discontinuation of the drug resulted in regression of the overgrowths. Histologic findings showed inflamed connective tissue covered by an acanthotic, thickened oral epithelium with long rete pegs containing dyskeratotic pearls. The proliferation rate and protein and collagen production of fibroblasts from the overgrowth sites were markedly lower than in the control cells cultured from healthy gingiva. Incubation of fibroblasts in the presence of verapamil reduced protein and collagen synthesis.     

Fumonisin B1-induced apoptosis in neuroblastoma, glioblastoma and hypothalamic cell lines

Fumonisin B(1) (FB(1)) is a mycotoxin produced by Fusarium verticilliodes, which commonly infects corn across the world. Fusarium fungi may also be found in moisture-damaged buildings. In this study, we investigated the role of apoptosis in the toxicity of FB(1) in four different cell lines. Activation of caspase-3-like protease, DNA fragmentation and expression of p53 and Bcl-2 family proteins were studied in mouse GT1-7 hypothalamic, rat C6 glioblastoma, human U-118MG glioblastoma, and human SH-SY5Y neuroblastoma cells exposed to 0.1-100microM FB(1) for 0-144h. Caspase-3-like protease activity increased in all cell lines, except SH-SY5Y, at 48-144h, and internucleosomal DNA fragmentation occurred in all of the cell lines, pointing to a role for apoptosis in the toxicity of FB(1). However, the expressions of p53 or pro- or antiapoptotic Bcl-2 family proteins (Bax, Bcl-2, Bcl-X(L) and Mcl-1) were not affected in any of the cell lines even after prolonged exposure to FB(1) at high doses. The results of this study, together with the results of our previous studies, provide evidence that FB(1) is a potential neurotoxin, but that the toxicity of FB(1) varies between different cell lines. The sensitivity of these cell lines towards FB(1) is as follows: U-118MG>GT1-7>C6>SH-SY5Y cells. These results are consistent with the assumption that cells of glial origin may be more sensitive towards FB(1) than cells of neural origin.     

A feasibility study of a web-based performance improvement system for substance abuse treatment providers

We report here on the feasibility of implementing a semiautomated performance improvement system—Patient Feedback (PF)—that enables real-time monitoring of patient ratings of therapeutic alliance, treatment satisfaction, and drug/alcohol use in outpatient substance abuse treatment clinics. The study was conducted in six clinics within the National Institute on Drug Abuse Clinical Trials Network. It involved a total of 39 clinicians and 6 clinic supervisors. Throughout the course of the study (consisting of five phases: training period [4 weeks], baseline [4 weeks], intervention [12 weeks], postintervention assessment [4 weeks], sustainability [1 year]), there was an overall collection rate of 75.5% of the clinic patient census. In general, the clinicians in these clinics had very positive treatment satisfaction and alliance ratings throughout the study. However, one clinic had worse drug use scores at baseline than other participating clinics and showed a decrease in self-reported drug use at postintervention. Although the implementation of the PF system proved to be feasible in actual clinical settings, further modifications of the PF system are needed to enhance any potential clinical usefulness.     

Mismatch negativity and late discriminative negativity in sleeping human newborns

Event-related potentials were recorded from sleeping newborns to compare amplitudes and latencies of mismatch negativity (MMN) and late discriminative negativity (LDN) in active and quiet sleep stages. MMN and LDN were obtained in response to changes in semi-synthesized vowels from 20 healthy newborn infants. MMN and LDN responses were significant for both active and quiet sleep. The amplitude and latency of MMN or LDN did not differ between the sleep stages. Thus, in contrast to adult studies that show a significant drop in the MMN amplitude and an increase in the MMN latency as the sleep gets deeper, arousal stages do not seem to effect either MMN or LDN characteristics in newborns. These results suggest functional differences between infant and adult sleep.     

Evaluation of the analgesic efficacy and psychoactive effects of AZD1940, a novel peripherally acting cannabinoid agonist,in human capsaicin‐induced pain and hyperalgesia

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High indoor microbial levels are associated with reduced Th1 cytokine secretion capacity in infancy

Background: Exposure to microbes and their components may affect the maturation of the immune system. We examined the association of house dust microbial content with cytokine-producing capacity at birth and at the age of 1 year. Methods: Production of TNF-α, IFN-γ, IL-5, IL-8 and IL-10 at birth (n = 228) and at the age of 1 year (n = 200) following 24- and 48-hour whole-blood stimulation with staphylococcal enterotoxin B (SEB), lipopolysaccharide and the combination of phorbol ester and ionomycin was measured. Concentrations of ergosterol (marker for fungal biomass), muramic acid (marker for Gram-positive bacteria) and 3-hydroxy fatty acids with a carbon chain length from 10 to 14 (marker for Gram-negative bacteria) in living room floor dust were analyzed using gas chromatography-tandem mass spectrometry. Five single microbial species or groups were determined using a quantitative polymerase chain reaction method. Results: A high total level of the studied Gram-positive bacteria in general or Mycobacterium spp. in house dust was associated with decreased SEB-stimulated IFN-γ production, especially at the age of 1 year. The total level of indoor fungi analyzed (Penicillium spp., Aspergillus spp. and Paecilomyces variotii group, Trichoderma viride/atroviride/koningii,Wallemia sebi) was also inversely associated with IFN-γ production at the age of 1 year, but this association did not remain significant after adjustment for potential confounders. A few associations were found between microbial exposures and other measured cytokines. Conclusions: High indoor microbial exposures may affect immune development in early life by reducing T helper type 1 cytokine secretion capacity. The observed hyporesponsiveness may reflect the adaptation of the immune system to environmental antigens. In future, more attention should be paid especially to the immunomodulatory role of exposures to Gram-positive bacteria.     

Prodrug Approaches for CNS Delivery

Central nervous system (CNS) drug delivery remains a major challenge, despite extensive efforts that have been made to develop novel strategies to overcome obstacles. Prodrugs are bioreversible derivatives of drug molecules that must undergo an enzymatic and/or chemical transformation in vivo to release the active parent drug, which subsequently exerts the desired pharmacological effect. In both drug discovery and drug development, prodrugs have become an established tool for improving physicochemical, biopharmaceutical or pharmacokinetic properties of pharmacologically active agents that overcome barriers to a drug's usefulness. This review provides insight into various prodrug strategies explored to date for CNS drug delivery, including lipophilic prodrugs, carrier- and receptor-mediated prodrug delivery systems, and gene-directed enzyme prodrug therapy.     

Altered control of submaximal bite force during bruxism in humans

The control of bite force during varying submaximal loads was examined in patients suffering from bruxism compared to healthy humans not showing these symptoms. The subjects raised a bar (preload) with their incisor teeth and held it between their upper and lower incisors using the minimal bite force required to keep the bar in a horizontal position. Further loading was added during the preload phase. A sham load was also used. Depending on the session, the teeth were loaded by the experimenter or the subject and in one session the subject did not see the load (no visual feedback). The bite force was measured continuously using a calibrated force transducer. In all the subjects, the bite force increased with increasing load. Following the addition of the load, the level of the tonic bite force was reached rapidly with no marked overshoot. The patients with bruxism used significantly higher bite forces to hold the submaximal loads compared to the control subjects. In the control subjects, the holding forces for each submaximal load were identical in the men and the women and were independent of subject maximal bite force. Sham loading evoked no marked responses in biting force. Whether the subject or the experimenter added the load or whether the subject had visual feedback or not were not significant factors in determining the level of bite force. The results indicated that the patients with bruxism used excessively large biting forces for each given submaximal load. This study showed no evidence that the inappropriate control of bite force by patients with bruxism was due to an abnormality in the higher cortical circuits that regulates the function of trigeminal motoneurons in the brainstem. This was shown by a lack of abnormality in coordination of voluntary hand movement with biting force, a lack of abnormal anticipation response to a sham load and a lack of any effect of visual feedback. The results were in line with the hypothesis that afferent input from oral (periodontal or masticatory muscle) tissues does not provide an appropriate control of motor command in bruxism.     

Diclofenac readily penetrates the cerebrospinal fluid in children

AIMS

The primary aim was to study the cerebrospinal fluid (CSF) penetration of intravenous diclofenac in children. The secondary aim was to evaluate the plasma diclofenac concentration at the onset of wound pain after inguinal surgery in children.

METHODS

A total of 31 children (24 boys) aged 3 months to 12 years received a single intravenous injection of diclofenac 1 mg kg⁻¹. Paired CSF and blood samples were obtained 5 min to 22 h (median 69 min) later. In children having inguinal surgery a second blood sample was obtained at the time that the children felt wound pain for the first time after surgery. Diclofenac concentrations in CSF, plasma and protein free plasma were measured by gas chromatography with mass spectrometric detection.

RESULTS

In the 28 CSF samples obtained at 5 min to 3 h 43 min after injection, diclofenac concentrations ranged between 0.5 and 4.7 μg l⁻¹. At 5.5 h the CSF concentration was 0.1 μg l⁻¹, and no diclofenac was detected in the two CSF samples obtained at 22 h. The median of plasma diclofenac concentration at the time when pain returned after inguinal surgery was 104 μg l⁻¹ (range 70–272 μg l⁻¹). No serious or unexpected adverse effects were reported.

CONCLUSIONS

Diclofenac penetrates the CSF rapidly, and a sufficient concentration to inhibit cyclooxygenase enzymes is sustained for up to 4 h.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Diclofenac, a nonselective nonsteroidal anti-inflammatory drug,, exerts analgesic action both in the peripheral tissues and in the central nervous system by inhibiting cyclooxygenase enzymes COX-1/2, but central nervous system penetration of diclofenac has not been evaluated in humans.

WHAT THIS STUDY ADDS

• Diclofenac penetrates the cerebrospinal fluid rapidly, and after a single intravenous dose of 1 mg kg⁻¹, sufficient concentrations to inhibit COX-1/2 are sustained for up to 4 h.