Cytokine expression correlates with differential sensory perception between lye and no-lye relaxers

Differences in perceived sensory scalp discomfort between guanidine carbonate/calcium hydroxide (no-lye) and sodium hydroxide (lye) relaxer technologies have been reported by users for decades. However, the biochemical processes responsible for the perceived differences have not been fully studied. We have used an in vitro three-dimensional skin model with well-developed epidermis to explore the expression of cytokines that may partially explain the biological response resulting in differences in sensory perception. The cytokines selected were prostaglandin E2 (PGE2), interleukin-1a (IL-1a), and IL-1 receptor antagonist (IL-1ra) because they have been shown to participate in irritant-induced discomfort. We show that lye relaxer induced over 350% increase in PGE2 expression over untreated control compared to 200% by no-lye in the early phase (4 h) postexposure epidermal response. Expression of IL-1a in the early phase showed no significant difference between lye and no-lye; however, no-lye induced higher levels (p < 0.0001) in 24 and 48 h. Concomitantly, no-lye induced increased expression of IL-1ra compared to lye at all time points. Given the association of PGE2 with nociceptive activation, these findings suggest that the perceived variation in sensory discomfort reported by consumers between lye and no-lye relaxers may be associated with differences in induced PGE2 expression.

Contact irritant responses of Aedes aegypti Using sublethal concentration and focal application of pyrethroid chemicals

BACKGROUND

Previous studies have demonstrated contact irritant and spatial repellent behaviors in Aedes aegypti following exposure to sublethal concentrations of chemicals. These sublethal actions are currently being evaluated in the development of a push-pull strategy for Ae. aegypti control. This study reports on mosquito escape responses after exposure to candidate chemicals for a contact irritant focused push-pull strategy using varying concentrations and focal application.

METHODS

Contact irritancy (escape) behavior, knockdown and 24 hour mortality rates were quantified in populations of female Ae. aegypti under laboratory conditions and validated in the field (Thailand and Peru) using experimental huts. Evaluations were conducted using varying concentrations and treatment surface area coverage (SAC) of three pyrethroid insecticides: alphacypermethrin, lambacyhalothrin and deltamethrin.

RESULTS

Under laboratory conditions, exposure of Ae. aegypti to alphacypermethrin using the standard field application rate (FAR) resulted in escape responses at 25% and 50% SAC that were comparable with escape responses at 100% SAC. Significant escape responses were also observed at <100% SAC using ½FAR of all test compounds. In most trials, KD and 24 hour mortality rates were higher in mosquitoes that did not escape than in those that escaped. In Thailand, field validation studies indicated an early time of exit (by four hours) and 40% increase in escape using ½FAR of alphacypermethrin at 75% SAC compared to a matched chemical-free control. In Peru, however, the maximum increase in Ae. aegypti escape from alphacypermethrin-treated huts was 11%.

CONCLUSIONS/SIGNIFICANCE

Results presented here suggest a potential role for sublethal and focal application of contact irritant chemicals in an Ae. aegypti push-pull strategy to reduce human-vector contact inside treated homes. However, the impact of an increase in escape response on dengue virus transmission is currently unknown and will depend on rate of biting on human hosts prior to house exiting.

Blunted behavioral and c Fos responses to acidic fumes in the African naked mole-rat

Acidosis in the skin triggers activation of pain pathways and behaviors indicative of pain in vertebrates. The exception is the naked mole-rat, the only known vertebrate to show physiological and behavioral insensitivity to acid pain in the skin. The goal of the present study was to determine behavioral and physiological responses of this species to airborne acidic fumes, which would be expected to affect the trigeminal pain pathway in other species. Behaviorally, naked mole-rats did not avoid fumes from moderately high concentrations of acetic acid (10 and 20%), and c Fos labeling showed no increase in activity in the trigeminal nuclei and nucleus tractus solitarius. In contrast, these concentrations triggered behavioral aversion and increased Fos activity in other laboratory rodents. For a very high concentration of acetic acid (50%), naked mole-rats showed significant avoidance behavior and increased Fos labeling in the nucleus tractus solitarius caudal region, which receives vagal chemosensory information. However, there was no increase in trigeminal labeling, and in fact, activity significantly decreased. This pattern is opposite of that associated with another irritant, ammonia fumes, which elicited an increase in trigeminal but not nucleus tractus solitarius Fos labeling, and no behavioral avoidance. Behavioral avoidance of acidic fumes, but no increased labeling in the trigeminal pain nucleus is consistent with the notion of adaptations to blunt acid pain, which would be advantageous for naked mole-rats as they normally live under chronically high levels of acidosis-inducing CO₂.

Characterization and evaluation of poly(epsilon-caprolactone) nanoparticles containing 2-ethylhexyl-p-methoxycinnamate, octocrylene, and benzophenone-3 in anti-solar preparations

Ultraviolet radiation can bring both harm and benefits to human health. Among those harms are erythemas, photosensitivity, photoaging, and the most worrying, skin cancer. Nanoencapsulation of sunscreen agents (SA) by using a biocompatible and biodegradable polymer such as poly(epsilon-caprolactone) (PCL) is advantageous as it increases the retention of UV absorbers in the skin, avoids systemic absorption, and consequently, improves water resistance and stability of the preparation. The aim of this work is to develop, characterize, and study the encapsulation of 3 different SA: 2-ethylhexyl-p-methoxycinnamate, benzophenone-3, and octocrylene in PCL nanoparticles (Nps). Nps were prepared by the solvent emulsification and evaporation method. The process yield was calculated, and the Nps were characterized in terms of size, polydispersity index (PI), morphology, zeta potential (ZP), encapsulation efficiency (EE) (%), and sunscreen agent content (SAC). The final formulations were submitted to the hen's egg test-chorioallantoic membrane (HET-CAM), chorioallantoic membrane-trypan blue staining (CAM-TBS), red blood cell (RBC), Draize tests, in vitro release, in vitro sun protection factor (SPF), UVA protection factor (PF-UVA), and photostability. All the Nps were in the nanometric scale. PI showed monodisperse systems. ZP became more negative as the Np were lyophilized and were added to the formulations. EE varied from 84 to 90%. The SAC went from 44 to 65 microg of sunscreen agents by milligram of Np. The process yield went from 60 to 76%. Nps were predominantly spherical and elliptical forms. The addition of Np diminished the release of the SA. The SPF increased with Np presence and helped to maintain the PF-UVA after irradiation. The HET-CAM assay evaluated the formulation as slightly irritant, CAM-TBS and RBC tests as non irritant, and the Draize test as moderately irritant.

Bioactive components in the fruits of Ziziphus jujuba Mill. against the inflammatory irritant action of Euphorbia plants

Chinese jujube (also known as Chinese date) is the fruit of Ziziphus jujuba Mill. (Rhamnaceae). As a famous folk medicine, it is used as antidote in traditional Chinese formula, Shi Zao Decoction, to relieve the drastic inflammatory irritant nature of Euphorbia species. The irritant activities may cause serious adverse effects in clinical practices. This study aimed to investigate the active components of Z. jujuba through the inhibitory effects on the inflammatory cells activated by Euphorbia kansui and prostratin, a phorbol ester isolated from Euphorbia fischeriana. Peritoneal macrophage of rat and splenic lymphocyte (splenocyte) of mouse were selected to evaluate these actions in vitro. Nitric oxide (NO) release of macrophage and the proliferation of splenocyte were examined through Griess method and MTT assay. TNF-α, as an important pro-inflammatory cytokines, was detected with enzyme-linked immunosorbent assay (ELISA) method. Six fractions extracted from Z. jujuba were evaluated and fraction F (triterpene acids fraction) was demonstrated to be the most active part, and then, 21 compounds isolated from Z. jujuba were tested at the concentrations range from 1 μg/ml to 100 μg/ml. The results show that 7 compounds of them are likely to be active compounds concerning to their pronounced inhibitory action on the activated inflammatory cells. These effects might be helpful to attenuate the irritant action of Euphorbiaceae plants and protect the gastrointestinal tissue from potent inflammatory injury, which should be beneficial to some diseases, like inflammatory bowel disease.

The acute phase response of cod (Gadus morhua L.): expression of immune response genes

An acute phase response (APR) was experimentally induced in Atlantic cod (Gadus morhua L.) by intramuscular injection of turpentine oil. The change in the expression of immune related genes was monitored in the anterior kidney and the spleen over a period of 7 days. The genes examined were two types of pentraxins, apolipoprotein A1 (ApoA-I), the complement component C3, interleukin-1β (IL-1β), transferrin, cathelicidin, and hepcidin. All genes were constitutively expressed in both organs and their expression amplified by the turpentine injection. A pattern of response was observed both with respect to the organ preference and to the timing of a maximum response. The increased gene expression of the pentraxins, ApoA-I and C3 was restricted to the anterior kidney, the gene expression of IL-1β, cathelicidin, and transferrin increased in both organs, while hepcidin gene expression was only significantly increased in the spleen. The pentraxins and ApoA-I appear to be early mediators of APR in cod, possibly stimulating C3 and IL-1β response, while the antimicrobial peptides may play a minor role. The increase in transferrin gene expression in both organs, and apparent indifference to cortisol release associated with the turpentine injection, suggests that this could be a typical acute phase protein in cod.

Failure of nebulized irritant, acidic, or hypotonic solutions or external mechanical stimulation of the trachea to consistently induce coughing in healthy, awake dogs

A useful approach for evaluating antitussive drugs in humans is to determine the sensitivity of the cough reflex to a standard challenge. The purpose of this study was to determine if methods used to induce coughing in humans would be effective when used on awake, untrained, healthy dogs for future application in therapeutic trials involving dogs with spontaneous disease. Methods tested were: mechanically stimulating the trachea by digital compression as well as by vibration from an electric shaver, neck massager, and palm sander (11 dogs), and administering nebulized irritant (3000 μM capsaicin), acidic (1 M citric acid), and hypotonic (deionized water) solutions using face masks (4 dogs). The threshold for success was defined as induction of at least 2 moderate or strong coughs in at least 75% of the dogs. None of the methods tested was successful. Digital compression induced soft (n = 2) or moderate (n = 1) coughing in 3 of 11 dogs tested. Nebulization of citric acid induced 1 soft cough in 1 of 4 dogs. It was concluded that coughing cannot be successfully induced in awake, healthy dogs using methods that are successful in humans. Other strategies must be developed so that cough sensitivity can be objectively and non-invasively measured in dogs for clinical research purposes.

Occupational contact dermatitis in manual cloud seeding operations

This is a case report on irritant contact dermatitis secondary to calcium oxide exposure during manual cloud seeding operations. A less hazardous substitute such as sodium chloride should be considered wherever possible. Cloud seeding operations are briefly discussed in this report, and the impact of calcium oxide exposure as an occupational hazard is elaborated.

Doxycycline hydrogels with reversible disulfide crosslinks for dermal wound healing of mustard injuries

Doxycycline hydrogels containing reversible disulfide crosslinks were investigated for a dermal wound healing application. Nitrogen mustard (NM) was used as a surrogate to mimic the vesicant effects of the chemical warfare agent sulfur mustard. An 8-arm-poly(ethylene glycol) (PEG) polymer containing multiple thiol (-SH) groups was crosslinked using hydrogen peroxide (H(2)O(2) hydrogel) or 8-arm-S-thiopyridyl (S-TP hydrogel) to form a hydrogel in situ. Formulation additives (glycerin, PVP and PEG 600) were found to promote dermal hydrogel retention for up to 24 h. Hydrogels demonstrated high mechanical strength and a low degree of swelling (< 1.5%). Doxycycline release from the hydrogels was biphasic and sustained for up to 10-days in vitro. Doxycycline (8.5 mg/cm(3)) permeability through NM-exposed skin was elevated as compared to non vesicant-treated controls at 24, 72 and 168 h post-exposure with peak permeability at 72 h. The decrease in doxycycline permeability at 168 h correlates to epidermal re-epithelialization and wound healing. Histology studies of skin showed that doxycycline loaded (0.25% w/v) hydrogels provided improved wound healing response on NM-exposed skin as compared to untreated skin and skin treated with placebo hydrogels in an SKH-1 mouse model. In conclusion, PEG-based doxycycline hydrogels are promising for dermal wound healing application of mustard injuries.

Loss of expression of TGF-βs and their receptors in chronic skin lesions induced by sulfur mustard as compared with chronic contact dermatitis patients

BACKGROUND

Sulfur mustard (SM) is a blister-forming agent that has been used as a chemical weapon. Sulfur mustard can cause damage in various organs, especially the skin, respiratory system, and eyes. Generally, the multiple complications of mustard gas result from its alkalizing potency; it reacts with cellular components like DNA, RNA, proteins, and lipid membranes.TGF-β is a multi-functional cytokine with multiple biological effects ranging from cell differentiation and growth inhibition to extracellular matrix stimulation, immunosuppression, and immunomodulation. TGF-β has 3 isoforms (TGF-β 1, 2, 3) and its signaling is mediated by its receptors: R1, R2 and intracellular Smads molecules.TGF-β has been shown to have anti-inflammatory effects. TGF-βs and their receptors also have an important role in modulation of skin inflammation, proliferation of epidermal cells, and wound healing, and they have been implicated in different types of skin inflammatory disorders.

METHODS

Seventeen exposed SM individuals (48.47 ± 9.3 years), 17 chronic dermatitis patients (46.52 ± 14.6 years), and 5 normal controls (44.00 ± 14.6 years) were enrolled in this study.Evaluation of TGF-βs and their receptors expressions was performed by semiquantitative RT-PCR. Only TGF1 was analyzed immunohistochemically.

RESULTS

Our results showed significant decreases in the expression percentages of TGF-β 1, 2 and R1, R2 in chemical victims in comparison with chronic dermatitis and normal subjects and significant decreases in the intensity of R1 and R2 expressions in chemical victims in comparison with chronic dermatitis and normal controls. (P value < 0.05)

CONCLUSIONS

TGF-βs and their receptors appear to have a noticeable role in chronic inflammatory skin lesions caused by sulfur mustard.

Irritant and co-carcinogenic diterpene esters from the latex of Euphorbia cauducifolia L

Ten (1-10) irritant and mild co-carcinogenic diterpene esters were isolated from the latex of Euphorbia cauducifolia L. using bioassay-guided countercurrent distribution and other chromatographic techniques. The isolated compounds were characterized on the basis of spectroscopic results and mass measurements. As an outcome, the ingenane-type esters were established with the following structures: 3-O-angeloyl-17-O-palmatoylingenol (1), 3-O-palmatoyl-5-O-angeloylingenol (2), 5-O-angeloyl-17-O-palmatoylingenol (3), 3-O-angeloyl-5-O-palmatoylingenol (4), 17-O-(2Z,4E,6Z)-2,4,6-tetradecatrienoyl-20-O-palmatoylingenol (5), 5-O-angeloyl-17-O-benzoylingenol (6), 5-O-angeloyl-17,20-diacetoxyingenol (7), 3-O-angeloyl-17-O-benzoyl-20-acetoxyingenol (8), 3-acetoxy-5-O-angeloyl-17-O-benzoylingenol (9), and 5-O-angeloyl-3,17,20-triacetoxyingenol (10). Their biological screening revealed that they are moderate irritants, and low to moderate tumor promoters compared to TPA, but hardly showed any solitary carcinogenic activity. The isolated esters represent new compounds and were not reported before from any source.

Mechanism of dinitrochlorobenzene-induced dermatitis in mice: role of specific antibodies in pathogenesis

BACKGROUND

Dinitrochlorobenzene-induced contact hypersensitivity is widely considered as a cell-mediated rather than antibody-mediated immune response. At present, very little is known about the role of antigen-specific antibodies and B cells in the development of dinitrochlorobenzene-induced hypersensitivity reactions, and this is the subject of the present investigation.

METHODOLOGY/PRINCIPAL FINDINGS

Data obtained from multiple lines of experiments unequivocally showed that the formation of dinitrochlorobenzene-specific Abs played an important role in the development of dinitrochlorobenzene-induced contact hypersensitivity. The appearance of dinitrochlorobenzene-induced skin dermatitis matched in timing the appearance of the circulating dinitrochlorobenzene-specific antibodies. Adoptive transfer of sera containing dinitrochlorobenzene-specific antibodies from dinitrochlorobenzene-treated mice elicited a much stronger hypersensitivity reaction than the adoptive transfer of lymphocytes from the same donors. Moreover, dinitrochlorobenzene-induced contact hypersensitivity was strongly suppressed in B cell-deficient mice with no DNCB-specific antibodies. It was also observed that treatment of animals with dinitrochlorobenzene polarized Th cells into Th2 differentiation by increasing the production of Th2 cytokines while decreasing the production of Th1 cytokines.

CONCLUSIONS/SIGNIFICANCE

In striking contrast to the long-held belief that dinitrochlorobenzene-induced contact hypersensitivity is a cell-mediated immune response, the results of our present study demonstrated that the production of dinitrochlorobenzene-specific antibodies by activated B cells played an indispensible role in the pathogenesis of dinitrochlorobenzene-induced CHS. These findings may provide new possibilities in the treatment of human contact hypersensitivity conditions.

Composition of the fresh leaves and stems of Melissa officinalis and evaluation of skin irritation in a reconstituted human epidermis model

The composition of a centrifuged product obtained from the fresh leaves and stems of Melissa officinalis and skin irritation in the reconstituted human epidermis (Episkin model) have been investigated in comparison to the EtOH-H(2)O (1:1) extract obtained by Soxhlet from the dried plant. Two new sulfated triterpenes (1 and 2) and two ionol derivatives have been isolated for the first time from Melissa officinalis together with caffeic and rosmarinic acids. The structures of compounds 1 and 2 were established by analysis of their spectroscopic data. Both the centrifuged material and its major constituents neither affected cell viability nor caused the release of pro-inflammatory mediators or the decrease of trans-epithelial electrical resistance (TEER) in the reconstituted human epidermis.

Inflammatory mediators released following application of irritants on the rat injured incisors. The effect of treatment with anti-inflammatory drugs

The exchange of fluids and chemicals between the tooth pulp and the periphery, through the dentinal tubules has been well documented. Application of irritants on the open tubules produces aversion in awake rats that can be prevented by prior occlusion of these tubules. This study aims at characterizing the secretion of inflammatory mediators in tooth perfusates and assessing the effects of systemic pretreatment with anti-inflammatory drugs on the levels of these mediators. Several groups of rats (n=5-6 each) were used for intradental application of either saline, capsaicin (100 microg in 100 microl), or endotoxin (20 microg in 100 microl) for a period of 40 min followed by filling the perfusion chamber with sterile saline and collecting the perfusate every 30 min for 6h. The perfusates were used for the determination of the concentrations of cytokines by ELISA. Application of irritants produced a highly significant increase in PGE2 (peak at 2h) and NGF (peak at 4-6h). Dexamethasone antagonized the effects of endotoxin and capsaicin, while NSAID affected mainly the endotoxin-induced inflammation. Our results confirm the validity of the tooth perfusion technique and demonstrate that the efficacy of treatment with anti-inflammatory drugs depends on the type of inflammation.

Investigation of the dermal sensitizing potential of traditional medical extracts in local lymph node assays

Traditional medical extracts are commonly used as complex mixtures, which may contain naturally occurring contact sensitizers. In this investigation, the mice local lymph node assay (LLNA) was performed to evaluate the dermal sensitization potential of Myrrh, Borneolum, Olibanum, Moschus and Cassia Bark, which are widely used in topical traditional medication. In the radioactive LLNA, the stimulation index (SI) values were calculated for each medical extract. Myrrh, Borneolum, Olibanum and Moschus induced dose-dependent cell proliferation and SI was more than 3. Cassia Bark showed no positive response over the range of test concentrations. In the flow cytometry analysis, the total number of CD3(+), CD4(+), and CD8(+) cells in local lymph nodes was increased in Moschus-, Olibanum-, Myrrh- and Borneolum-treated mice. The ratio of the B220(+)/CD3(+) (B/T cell ratio) and the percentage of I-A(k+) cells that was also positive for the CD69 marker (I-A(k+)/ CD69(+)) were increased in the Moschus-, Olibanum- and Myrrh-treated mice. However, no ofbvious change was observed in Borneolum-treated mice. Cassia Bark did not induce changes in the lymphocyte subpopulations. These results indicate that Moschus, Olibanum and Myrrh can be regarded as sensitizers, and Borneolum regarded as an irritant. Cassia Bark is neither a sensitizer nor an irritant. The combination of radioactive and flow cytometric LLNA can be used for the prediction of sensitizing potential of medical extracts which lead to allergic contact dermatitis in humans.

Differences between molecular mechanisms involved in the regulation of haptoglobin gene expression during the acute phase response and dietary restriction

Haptoglobin is a glycoprotein involved in the acute phase response. Previously we reported that haptoglobin gene expression was up-regulated during dietary restriction in young female rats. The present study aimed at determining whether chronic dietary restriction affects haptoglobin blood levels through changing levels and/or activities of IL-6-related transcription factors STAT and C/EBP in the liver as is the case during the acute phase response. To this end, we compared a female Wistar rat model of 50% 6-week-long dietary restriction with the standard laboratory model for the acute phase response induced by turpentine administration. During the turpentine-induced acute phase response, the transitory 5.4-fold increase of rat haptoglobin expression was accompanied by a prominent rise of serum IL-6 concentration and the increased binding of STAT3 and 35kD C/EBPbeta/LAP transcription factors to the haptoglobin gene hormone-responsive element. Results obtained after immunoblotting and DNA affinity chromatography (using hormone-responsive element) suggest that the stable 1.7-fold increase of serum haptoglobin level during dietary restriction was the result of increased amounts and activities of constitutive transcription factors C/EBPalpha and STAT5b, and to a smaller extent of STAT3. When dietary restriction rats were administered turpentine, a 8.7-fold increase in haptoglobin expression was followed by a considerable increase in the amount and hormone-responsive element binding activity of STAT3 but not 35kD C/EBPbeta/LAP. We concluded that haptoglobin gene up-regulation during chronic dietary restriction was regulated by different mechanisms than during the acute phase response, and that it depended on the amount(s) and activit(ies) of transcription factor(s) that characterize low-grade inflammatory conditions.

Exogenous galanin regulates capsaicin-evoked substance P release from primary cultured dorsal root ganglion neurons

OBJECTIVES

To determine the effect of exogenous galanin on capsaicin-evoked substance P (SP) release from primary cultured embryonic rat dorsal root ganglion (DRG) neurons.

METHODS

DRG was dissected out from embryonic 15-day-old Wistar rat and cultured as dissociated cells for 2 days then exposed to galanin (1 nmol/L, 10 nmol/L, 100 nmol/L). After 4 days incubation with exogenous galanin, the levels of mRNAs for SP and vanilloid receptor 1 (VR1) and protein for VR1 were estimated by RT-PCR and Western blot, respectively. Basal SP release and capsaicin-evoked SP release levels were measured by radioimmunoassay (RIA).

RESULTS

The amount of VR1 mRNA and VR1 protein expression and capsaicin-evoked SP release in cultured DRG neurons increased significantly after incubation with exogenous galanin compared with control DRG neurons at the same time point, whereas the amount of SP mRNA and basal SP release were not affected after incubation with exogenous galanin.

DISCUSSION

Exogenous galanin may promote capsaicin-evoked SP release from primary cultured DRG neurons. The elevation of the levels of VR1 mRNA and VR1 protein induced by exogenous galanin implicated that VR1 may be involved in the mechanisms of SP release evoked by capsaicin.

Effect of Skin Sensitizers on Inducible Nitric Oxide Synthase Expression and Nitric Oxide Production in Skin Dendritic Cells: Role of Different Immunosuppressive Drugs

Nitric oxide (NO) is involved in the pathogenesis of acute and chronic inflammatory conditions, namely in allergic contact dermatitis (ACD). However, the mechanism by which NO acts in ACD remains elusive. The present study focuses on the effects of different contact sensitizers (2,4-dinitrofluorbenzene, 1,4-phenylenediamine, nickel sulfate), the inactive analogue of DNFB, 2,4-dichloronitrobenzene, and two irritants (sodium dodecyl sulphate and benzalkonium chloride) on the expression of the inducible isoform of nitric oxide synthase (iNOS) and NO production in skin dendritic cells. It was also studied the role of different immunosuppressive drugs on iNOS expression and NO production. Only nickel sulfate increased the expression of iNOS and NO production being these effects inhibited by dexamathasone. In contrast, cyclosporin A and sirolimus, two other immunosuppressive drugs tested, did not affect iNOS expression triggered by nickel.

Impaired glutathione-conjugating capacity by cryopreserved human and rat hepatocytes

The activity of glutathione transferase was measured in sonicates of fresh rat hepatocytes and of cryopreserved rat, human and dog hepatocytes in the presence of added glutathione and by using 1-chloro-2,4-dinitrobenzene (CDNB) as non-selective substrate. The glutathione-conjugating capacity was also investigated in the presence of CDNB alone (without glutathione) with intact fresh rat hepatocytes and cryopreserved rat and human hepatocytes. Finally, the intracellular level of glutathione was measured in these hepatocytes. The specific activity of glutathione transferase in sonicates of fresh rat hepatocytes (in the presence of added GSH and CDNB) was about 415 nmol/min/10(6) cells. The corresponding activities in cryopreserved rat, human and dog hepatocytes were approximately 320, 440 and 540 nmol/min/10(6) cells, respectively. In contrast, glutathione conjugation by the intact cryopreserved human and rat hepatocytes in the presence of CDNB alone was less than 10% of the corresponding conjugation by fresh rat hepatocytes, indicating that glutathione was depleted in these cryopreserved hepatocytes. Glutathione depletion was confirmed after analytical measurement of the glutathione levels in fresh and cryopreserved hepatocytes. In fresh rat hepatocytes the level of glutathione was 44 nmol/10(6) cells, whereas it was 2.5 and 4.4 nmol/10(6) cells in cryopreserved rat and human hepatocytes, respectively. In summary, glutathione transferase was active in these cryopreserved hepatocytes but the cryopreservation procedure likely causes depletion in the intracellular level of glutathione, resulting in an overall reduced glutathione conjugating capacity.

The roles of mediators, irritants and allergens in causing mucin secretion from the trachea

Two species, the cat and the goose, have been investigated to determine whether a variety of pharmacological mediators, irritants and allergens change the rate at which mucins (mucus glycoproteins) are secreted into the trachea. Mucins were labelled by the administration of radioactive precursors which the mucous cells took up and incorporated into glycoproteins. These were periodically washed out of a segment of trachea with physiological saline solution. Changes in the amount of mucin secreted were estimated from measurements of the amount of bound radioactivity in tracheal washings. Histamine increased mucin secretion but the effects were stronger and more consistent in the goose than in the cat. A variety of prostaglandins increased the secretion in both species. 5-Hydroxytryptamine failed to stimulate mucin output in the cat. Ammonia and cigarette smoke both increased mucin secretion in the cat and preliminary results suggest that this was by a combination of local and reflex mechanisms. O-Chlorobenzilidine malononitrile increased secretion from the goose trachea entirely by a local mechanism. Preliminary experiments in which sensitized cats were challenged by various routes have equivocal results on whether anaphylaxis increases airway mucin secretion. It is concluded that irritants cause mucin secretion both by reflexes and local mechanisms. The mechanisms for the latter may well include release of pharmacological mediators.

TRPA1 receptor localisation in the human peripheral nervous system and functional studies in cultured human and rat sensory neurons

TRPA1 is a receptor expressed by sensory neurons, that is activated by low temperature (<17 degrees C) and plant derivatives such as cinnamaldehyde and isoeugenol, to elicit sensations including pain. Using immunohistochemistry, we have, for the first time, localised TRPA1 in human DRG neurons, spinal cord motoneurones and nerve roots, peripheral nerves, intestinal myenteric plexus neurones, and skin basal keratinocytes. TRPA1 co-localised with a subset of hDRG neurons positive for TRPV1, the heat and capsaicin receptor. The number of small/medium TRPA1 positive neurons (< or =50 microm) was increased after hDRG avulsion injury [percentage of cells, median (range): controls 16.5 (7-23); injured 46 (34-55); P<0.005], but the number of large TRPA1 neurons was unchanged [control 19.5 (13-31); injured 21 (11-35)]. Similar TRPA1 changes were observed in cultured hDRG neurons, after exposure to a combination of key neurotrophic factors NGF, GDNF and NT-3 (NTFs) in vitro. We used calcium imaging to examine responses of HEK cells transfected with hTRPA1 cDNA, and of human and rat DRG neurons cultured with or without added NTFs, to cinnamaldehyde (CA) and isoeugenol (IE). Exposure to NTFs in vitro sensitized cultured human sensory neuronal responses to CA; repeated CA exposure produced desensitisation. In rDRG neurons, low (225 microM) CA preincubation enhanced capsaicin responses, while high (450 microM and 2mM) CA caused inhibition which was partially reversed in the presence of 8 bromo cAMP, indicating receptor dephosphorylation. While TRPA1 localisation is more widespread than TRPV1, it represents a promising novel drug target for the treatment of chronic pain and hypersensitivity.

Anti-tumor 12-deoxyphorbol esters from Euphorbia cornigera

Nine (1-8 and 10) new and two (9 and 11) known compounds have been isolated from roots of Euphorbia cornigera Boiss. Their structure and relative stereochemistry were acquired through NMR ((1)H, (13)C, COSY-45, HOHAHA, HMQC, HMBC, NOE and HMBC) spectroscopic measurements. Compounds 1-10 were identified as diesters of 13,20-O-diacyl and 11 as 13-O-acetyl of 12-deoxyphorbol. Cytotoxic activity of the compounds was investigated on human KB cells by reduction of MTT. Compounds 8-10 displayed IC(50) of 0.8, 0.5, and 1.0 microg mL(-1), respectively, whereas the activity of rest of the compounds (1-7) was either very low or (11) zero even up to 1000 microg mL(-1). The inhibition of DNA synthesis through Trypan blue exclusion and Brd-U assay was investigation to figure out the role of compounds 8-10 and concluded that these were responsible for the death of KB cells. Significant correlation has been found between the cytotoxicity and DNA cross-link and DNA strand-break formation.

Irritant and cytotoxic coumarins from Angelica glauca Edgew roots

Irritant and cytotoxic potentiality of six coumarins, isolated for the first time from the roots of Angelica glauca identified as 5,6,7-trimethoxycoumarin, 6-methoxy-7,8-methylenedioxycoumarin, bergapten, decursinol angelate, decursin, and nodakenetin, were investigated. The irritant potential was explored by open mouse ear assay, evaluating their ID(50) after acute and by IU (Irritant units) after chronic effects, while the cytotoxic capability was explored by their LC(50), using brine shrimp (Artemia salina) larvae (nauplii). All the coumarins exhibited well-defined irritancy on mouse's ears, compared with the positive controlled euphorbium reaction and cytotoxic response against brine shrimp larvae, compared with the positive control colchicine. Decursinol angelate and decursin were the most potent and persistent irritant compounds with least ID(50), whose reactions lasted for 48 h. 6-Methoxy-7,8-methylenedioxycoumarin and bergaten revealed an intermediate irritant reactions, while 5,6,7-trimethoxycoumarin and nodakenetin displayed the least irritant and least persistent reactions on mouse ears. Both decursin and decursinol angelate also appeared to be the stronger cytotoxic agents than other coumarins. 5,6,7-trimethoxycoumarin displayed an intermediate cytotoxic behaviour, while other three coumarins, i.e., 6-methoxy-7,8-methylenedioxycoumarin, bergapten, and nodakenetin, exhibited the least cytotoxic capacity against brine shrimp larvae.

The differences in human cumulative irritation responses to positive and negative irritant controls from three geographical locations

A retrospective analysis was conducted to evaluate whether studies from three geographically diverse locations have similar response profiles to the positive and negative controls in a standard 14-day cumulative irritation study (1). The positive irritant control (0.1% sodium lauryl sulfate, SLS) and the negative control (0.9% sodium chloride, saline) data from seventeen 14-day cumulative irritation studies were reviewed. The studies were compiled from three locations representing dry/hot, humid/hot, and dry/cold environments (Scottsdale, Arizona; St. Petersburg, Florida; and Winnipeg, Manitoba, respectively). Irritation scores were generated by trained skin graders from a total of 442 subjects studied between 1999 and 2005. Cumulative irritation scores were reviewed and compared between study locations. The irritation scores for the positive and negative controls were not significantly different between locations. Temperature and relative humidity (RH) variation did not correlate significantly with overall irritation. However, the dryer climate (i.e., negative or low dew point) had a tendency to induce a higher overall irritation level for both positive and negative controls.