In this study, the nociceptive responses induced by subcutaneous injection of scorpion BmK venom into the plantar surface of rat hind paw were quantified. The suitable dose of the venom is between 0.01 and 0.05 mg. The venom injection could induce local edema and tonic-pain responses, which had lasted more than 1 h. The pain scores reached peak intensity within 20 min, and then decreased slowly. Morphine, as a classic analgesic drug, could inhibit the spontaneous nociceptive response induced by the venom. With Morphine pretreatment, the mean pain scores for the entire 60 min were significantly decreased (P<.05). BmK I, a main lethal component, was also found to induce nociceptive responses with dose-dependent means. The nociceptive responses induced by BmK I could be partially inhibited by morphine.

Analgesics, Opioid↗

PubMedDate not supplied

Effects of eliminating retinal Y cell input on center-surround interactions in the dorsal lateral geniculate nucleus of the cat.

The aim of this project was to investigate the interaction between Y retinal ganglion cells and the cells of the dorsal lateral geniculate nucleus (LGNd) of the cat, with particular reference to center-surround antagonism and intrageniculate inhibition. Responses of cells in the LGNd were studied by stimulating the retina with spots of light of constant contrast but varying size. The peak discharges of nonlagged X (XN) cells were strongly suppressed with increase in spot size but the responses of lagged X (XL) cells and nonlagged Y (YN) cells were inhibited much less strongly. The effect of the Y system on these responses was examined by producing a selective block of conduction in Y fibers in one optic nerve by means of a pressure cuff (Y-blocking). These effects were assessed by measuring the peak discharge rates and by calculation of a "peak suppression index." Y-blocking had no significant effect on the peak suppression index of XL cells in either lamina or on YN cells in the normal (not Y-blocked) lamina but had significant effects on the responses of XN cells, causing a decrease in peak suppression index, both for cells in laminae receiving their principal excitatory input from the Y-blocked eye (both lamina A and lamina A1) as well as those in lamina A (but not lamina A1) receiving their excitatory input from the normal eye. These effects were obtained with relatively large spots of light. Thus Y optic fibers have both intralaminar (monocular) and interlaminar (binocular) inhibitory effects on XN cells. In addition to these suppressive effects, the experiments also show that ipsilaterally projecting Y fibers have facilitatory effects on XN cells in lamina A when small spots of light, about optimal size for the XN cell, are used. These results suggest that the Y system plays a powerful role in shaping the responses of XN cells, possibly enhancing visual acuity.

Animals↗

PubMedDate not supplied

Self-assembled peptides exposing epitopes recognizable by human lymphoma cells.

A bifunctional N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer containing nitrilotriacetic acid (NTA) and benzophenone (BP) groups was synthesized by free-radical copolymerization of HPMA, 2-methacrylamidobutyl nitrilotriacetic acid (MABNTA), and 4-methacrylamido benzophenone (MABP) using 2, 2'-azobisisobutyronitrile (AIBN) as initiator. A His-tagged coiled coil stem loop peptide containing a tridecapeptide (TDP) epitope (GFLGEDPGFFNVE) in the loop region (CCSL-TDP) was designed and synthesized genetically by expressing an artificial gene in Escherichia coli BL21 (DE3). The peptide was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), size-exclusion chromatography (SEC), and circular dichroism (CD) spectroscopy. Surfaces containing self-assembled CCSL-TDP peptide were prepared by first covalently grafting poly(HPMA-co-MABNTA-co-MABP) onto polystyrene (PS) surface by UV irradiation, then charging the surface with nickel through NTA groups, and finally attaching the CCSL-TDP peptide through Ni-histidine chelation. The modified PS surfaces with and without self-assembled CCSL-TDP peptide were characterized by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Cell attachment studies with human Burkitt's lymphoma Raji B cells showed that the cells selectively bound to the self-assembled CCSL-TDP peptide surfaces, but not to the surfaces of PS, PS with grafted copolymer, and PS with grafted copolymer and self-assembled coiled coil peptide with similar structure but without the epitope. This indicates that the cell attachment was mediated by the CCSL-TDP peptide, most probably by the TDP epitope region. The CCSL peptide self-assembly presented here may represent a feasible model of exposing epitopes for biorecognition studies.

Acrylamides↗

PubMedDate not supplied

Directed evolution of metabolically engineered Escherichia coli for carotenoid production.

We have previously introduced a reconstructed isoprenoid pathway into Escherichia coli that exhibits amplified biosynthetic flux to geranylgeranyl diphosphate (GGPP), a common isoprenoid precursor. It was shown that GGPP synthase is an important rate-controlling enzyme in this reconstructed isoprenoid pathway. In this investigation, we applied directed evolution to GGPP synthase from Archaeoglobus fulgidus to enable the enhanced production of carotenoids in metabolically engineered E. coli. Eight mutants were isolated, and the best one increased lycopene production by 100%. Among the mutants that were isolated, mutation points were clustered in four "hot regions". The "hottest" region is located in the sequence upstream of the coding region, which presumably improves the expression level of the enzyme. The other three are within the coding sequence and are believed to improve the enzyme-specific activity in E coli. These results demonstrate that modulating both enzymatic expression and specific activity are important for optimizing the metabolic flux distribution.

Base Sequence↗

PubMedDate not supplied

Enhanced taxol production and release in Taxus chinensis cell suspension cultures with selected organic solvents and sucrose feeding.

Suspension culture of Taxus chinensis cells was carried out in aqueous-organic two-phase systems for the production and in situ solvent extraction of taxol (paclitaxel). Three organic solvents, hexadecane, decanol, and dibutylphthalate, were tested at 5-20% (v/v) in the culture liquid. All of these solvents stimulated taxol release and the yield per cell, though decanol and higher concentrations of the other two solvents depressed biomass growth significantly. Ten percent dibutylphthalate was the optimal solvent for improving taxol production and release with minimal cell growth inhibition. The time of solvent addition to the culture also affected taxol production, with the addition during the late-log growth phase being most favorable. By feeding sucrose to the culture near the stationary growth phase, the cell growth and taxol production period was extended from 27 to 42 days. The combining of the two-phase culture and sucrose feeding increased the taxol yield by about 6-fold compared with the single-phase batch culture, to 36.0 +/- 3.5 mg/L, with up to 63% taxol released. This study shows that in situ solvent extraction combined with nutrient feeding is an effective process strategy for production and recovery of secondary metabolites in plant cell suspension culture.

Cell Culture Techniques↗

PubMedDate not supplied

Is male reproductive health at risk? Longitudinal semen analysis studies.

Explore the source record for details and available documents.

Fertility↗

PubMedDate not supplied

Solar ultraviolet radiation and skin damage: an epidemiological study among a Chinese population.

To explore skin damage resulting from solar ultraviolet radiation on Mongoloid people, we investigated 470 healthy people in northeast China. We assessed their skin texture and elastic fibers, number of Langerhans cells, and the incidence of p53 gene mutations. The results showed that solar ultraviolet radiation played a significant role in aging of skin in Chinese people; aging began at 30 y of age (i.e., 20 y later than in Caucasians). In the high-exposure group, aging of skin was twice as severe and occurred 10 y earlier than in the low-exposure group. The counts of Langerhans cells had a tendency to decrease in the high-exposure group. Neither p53 mutations nor solar keratosis were found in individuals of any age-findings that indicated a qualitative different pattern than that of Caucasians.

Adolescent↗

PubMedDate not supplied

Heterogenous and compartment-specific activation of nonlymphocytic, mononuclear cells in intraabdominal sepsis.

Although sepsis is associated with increased production of cellular pro- and anti-inflammatory mediators by monocyte/macrophages, the compartmentalization and nature of such activation has not been clearly defined. The authors examined the activation of nonlymphocytic mononuclear cells in different compartments in the cecal ligation and puncture (CLP) model of septic peritonitis. Control and CLP rat mononuclear cells from the peritoneal cavity, bronchoalveolar, as well as the lung vascular compartment were isolated 24 and 48 hours post surgery and release of nitric oxide (NO), interleukin (IL)-12, and monocyte chemoattractant protein-1 (MCP-1) was measured from culture media. Peritoneal macrophages (PMs) from CLP rats increased release of all three mediators compared to controls. Cells from the lung vascular compartment after CLP increased release of NO, but MCP-1 release was unchanged. Levels of IL-12 were not detectable. Similarly, bronchoalveolar macrophages (BMs) of CLP rats had increased release of NO, whereas IL-12 was not detectable. Release of MCP-1 increased 48 hours after CLP. Almost all PMs and BMs possessed innate phagocytic ability that was not altered during sepsis. The percentage of cells in the lung vascular compartment that had phagocytic ability, increased 48 hours post CLP, versus controls. The authors also evaluated lung injury at 24 hours after surgery by measurement of bronchoalveolar lavage protein and LDH activity. There was an increase in both these parameters 24 hours after CLP as compared to controls. Thus, there was heterogenous and compartment-specific activation of mononuclear cells in sepsis. There was nonspecific inflammatory activation in the primary site of injury. In a remote organ (lung), the authors show for the first time that there was selective activation of NO without increased release of the proinflammatory cytokine, IL-12. Phagocytic activity was maintained in the bronchoalveolar compartment whereas in the lung vascular compartment, the percentage of phagocytic cells increased.

Animals↗

PubMedDate not supplied

Preparation and in vitro release behaviour of 5-fluorouracil-loaded microspheres based on poly (L-lactide) and its carbonate copolymers.

A modified oil-in-oil (o/o) emulsion solvent evaporation technique was adopted to prepare 5-fluorouracil (5-Fu)-loaded poly (L-lactide) (PLLA) or its carbonate copolymer microspheres. The disperse phase was a drug:polymer solution using a solvent mixture of N,N-dimethylformamide (DMF) and acetonitrile and the continuous phase was liquid paraffin containing 1-10% (w/v) Span 80(R). The effects of preparative parameters, such as the composition of the inner oil phase, drug:polymer ratio, polymer concentration and agitation rate, on 5-Fu entrapment efficiency and microsphere characteristics were investigated. By introducing 25% (v/v) DMF into the inner oil phase, microspheres with high drug entrapment efficiency and an ameliorated burst effect were achieved. Using this modified method, microspheres with various particle sizes could be produced with a high 5-Fu entrapment efficiency (about 80%). In vitro drug release tests showed a burst release of 5-Fu from PLLA microspheres, followed by a sustained release over 50 days. In the case of poly (L-lactide-co-1,3-trimethylene carbonate) (PLTMC) and poly (L-lactide-co-2,2-dimethyl-1,3-trimethylene carbonate) (PLDTMC), the drug release could be continued for over 60 days.

Biocompatible Materials↗

PubMedDate not supplied

Areas PMLS and 21a of cat visual cortex: two functionally distinct areas.

We have compared the receptive field properties of neurons recorded from visuotopically corresponding regions of area 21a and the posteromedial lateral suprasylvian area (PMLS) of cat visual cortex. In both areas, the great majority of neurons were orientation-selective and binocular, and their responses to moving contours were modulated by simultaneous in-phase or anti-phase motion of large textured background stimuli ('visual noise'). However, despite the great hodological similarity between the two areas, PMLS neurons had on average significantly higher peak discharge rates, exhibited substantially greater direction selectivity indices, and preferred substantially higher stimulus velocities than area 21a neurons. Furthermore, the majority of binocular neurons in the PMLS area and in area 21a were dominated respectively by contralateral and ipsilateral eyes. Finally, while 46% of PMLS neurons were excited by movement of visual noise per se, only 25% of area 21a neurons could be excited by such stimuli. We argue that the PMLS area, like its presumed primate homologue the middle-temporal (MT) area, is mainly involved in motion analysis. By contrast, area 21a appears to be involved in pattern analysis rather than motion analysis. It is likely that phylogenetically area 21a derives from the PMLS area.

Animals↗

PubMedDate not supplied

Efficacy and safety of imipenem/cilastatin: a review of worldwide clinical experience.

The clinical experience of 1,723 patients treated with imipenem/cilastatin in worldwide clinical trials is reviewed. Dosages of imipenem administered parenterally with cilastatin varied with the severity of the infection and included 250 mg four times a day; 500 mg three or four times a day, and 1 g three of four times a day. Infections of all body systems except the central nervous system due to gram-positive or gram-negative aerobes and anaerobes as well as those due to mixed organisms were treated. Clinical efficacy was demonstrated in 92% of infections. The adverse clinical and laboratory experiences associated with imipenem/cilastatin were similar to those of other beta-lactam agents and included disturbances of gastrointestinal and central nervous system function, allergic reactions, and transient elevations of liver enzyme levels.

Adult↗