Lambda Carrageenan Research Articles

Structure and performance of commercial kappa-2 carrageenan extracts: I. Structure analysis

Extracts of two Chilean carrageenophyte red seaweeds, Sarcothalia crispata and Gigartina skottsbergii, were prepared by each of two industrial processes: a mild alkaline extraction with aqueous sodium hydroxide and a more vigorous aqueous alkaline extraction with lime. The resulting extracts, recovered by precipitation with isopropyl alcohol, were separated into gelling and non-gelling fractions by leaching with 2.5% KCl. These processes were also applied to Chondrus crispus and to separated gametophyte and sporophyte samples of the Chilean seaweeds for comparative purposes. The carrageenan compositions of these extracts and fractions were determined using both chemical and spectroscopic techniques. In addition, a set of decision rules is proposed and applied to convert data from glycosyl linkage analysis to carrageenan composition. The gametophyte extracts contained mixtures/hybrids of kappa and iota carrageenans (and also mu and nu carrageenans, depending on the extraction conditions used). The tetrasporophyte extracts contained lambda carrageenan (and also theta carrageenan, depending on the extraction conditions used). Extractive fractionation of mixed life phase samples using 2.5% KCl yielded insoluble, ‘gelling’ carrageenans quite similar to those from a gametophyte extract of the same species, but the soluble, non-gelling fractions were not the same as the corresponding sporophyte extracts.

A comparison of chronic aspartame exposure to aspirin on inflammation, hyperalgesia and open field activity following carrageenan-induced monoarthritis

The purpose of the present study was to investigate whether chronic aspartame exposure possesses analgesic and anti-inflammatory actions in the carrageenan-induced monoarthritis model similar to those properties of aspirin. Prior research demonstrated that aspartame can reduce second phase formalin pain and increase motor activity in arthritic patients. Fifty-eight male Sprague-Dawly rats were treated with aspartame (25, 50, 100 mg/kg) or saline for six days. An additional group of animals received daily injections of saline and on the sixth treatment day, received a 150-mg/kg dose of aspirin 30-minutes prior to behavioral testing. On Day 6, animals received an intra-articular (i.a.) injection of 2% lambda carrageenan (CARR) or an equal volume of saline and were tested four hours later on threshold to mechanical and thermal stimuli, open field activity, and knee joint diameter. Aspirin-treated arthritic animals exhibited significantly less mechanical hyperalgesia and knee joint inflammation compared with vehicle treated arthritic animals. However, aspirin did not reverse thermal hyperalgesia or increase motor activity to control levels. Aspartame did not reduce inflammation, increase motor activity, or attenuate thermal allodynia, but at 50 mg/kg did attenuate mechanical allodynia compared with vehicle treated arthritic animals. The anti-hyperalgesic effect on mechanical hyperalgesia was not seen at 25 mg/kg or 100 mg/kg aspartame. These results suggest that a certain amount of aspartame may provide relief of arthritic pain to a similar degree as aspirin in some individuals. The specific effect of aspartame and aspirin on mechanical hyperalgesia should be considered when these agents are used for the therapeutic treatment of arthritic conditions.

Separation of iota-, kappa and lambda-carrageenans by capillary electrophoresis.

The present study reports a novel method for the separation of the high-molecular-weight anionic polysaccharides, iota, kappa, and lambda carrageenans, in capillary electrophoresis (CE). Carrageenan samples are first derivatised with 9-aminopyrene-1,4,6-trisulfonic acid (APTS), separated in an ammonium acetate background electrolyte (BGE) and detected with laser-induced fluorescence (LIF). The effects of changes of instrumental parameters (temperature, injection mode, field strength) and the composition of the BGE (concentration and pH) are reported, and are explained in terms of the physical chemistry of the BGE and the biopolymers. Optimal separation conditions for kappa, iota, and lambda carrageenans, including an APTS internal standard, were found in a polyvinyl alcohol coated capillary with an ammonium acetate BGE of low concentration (25 mM) and moderate pH (8.0). This BGE gave the best reproducibility in tests on iota/kappa mixtures, with relative standard deviations (RSDs) in migration times and normalised peak areas (relative to the APTS internal standard) of less than 0.1% and 1%, respectively. Using this BGE at 50 degrees C and a voltage of 30 kV, all three carrageenan subtypes were separated in a run time of 3 min.

The Chondrus crispus-Acrochaete operculata host-pathogen association, a novel model in glycobiology and applied phycopathology

A review is presented of ongoing research on the oligosaccharide signals involved in cell-cell recognition in the Chondrus crispus-Acrochaete operculata host-pathogen association. In this pathosystem, the host gametophytes are resistant to the pathogen, whereas the sporophytic generation is susceptible to infection. The virulence of the green algal pathogen is mediated by the recognition of carrageenan oligosaccharides released from its red algal host: kappa-carrageenan oligosaccharides inhibit A. operculata virulence while lambda carrageenan oligosaccharides enhance its pathogenicity. It appears that the recognition of A. operculata by C. crispus also involves an oligosaccharidic signal. This signal is present in the non-virulent form of the pathogen whereas it is absent from the virulent form. Altogether this pathosystem offers a unique model to investigate the recognition of oligosaccharide signals in plant-pathogen interactions. The possible applications of this research to develop new strategies for disease control in maricultured algal crops are discussed.

Preliminary safety and acceptability of a carrageenan gel for possible use as a vaginal microbicide

Objective: We sought to determine the safety and acceptability of vaginal gel formulation PC-503 among low risk, abstinent women. The active ingredient was 2% pharmaceutical grade lambda carrageenan, a sulphated...

Interactions of different carrageenan isoforms and flour components in breadmaking.

The aim of this study was to compare the effects of carrageenans with different sulfate contents on bread volume and dough rheological properties. Results showed that only lambda carrageenan, the most sulfated isoform, produced a significant increase in bread volume. In contrast, the different carrageenans induced a negative effect on the cookie factor. Alveographic and farinographic analyses indicated that dough rheological properties were differentially modified depending on whether lambda carrageenan was added to flour and then hydrated or vice versa. Analysis of the interaction between lambda carrageenan and flour components by infrared spectroscopy and SDS-PAGE indicated that a pool of low molecular weight hydrophobic gluten proteins interact with carrageenan. This interaction drastically changes their physicochemical properties since carrageenan-gluten protein complexes show a hydrophilic behavior. In addition, the results indicate that carrageenan sulfate groups and probably the amino groups of glutamines present in the primary structure of gluten proteins are involved in the interaction.

Characterization of a diltiazem-lambda carrageenan complex

In the present paper the interaction between lambda carrageenan, a natural sulphated polysaccharide, and diltiazem HCl, a Ca channel blocking agent, was studied. Dialysis equilibria were performed to quantify the binding capacity of lambda carrageenan for diltiazem. The relevance of the interaction to hydrophilic matrix systems was confirmed: a relationship was found between the binding capacity and the release profiles of matrix tablets containing a fixed amount of drug and different percentages of lambda carrageenan. Dialysis equilibria in buffered media showed that the interaction is quite insensitive to the pH of the medium (in the range 1.8–6.8), while it is reduced by increasing ionic strength; this behaviour is in line with the importance of ionic bonds in diltiazem-carrageenan interaction. On the basis of the calculated binding capacity, the complex was prepared, dried and milled. A preliminary characterization of the diltiazem-carrageenan complex in the solid state was effected by means of X-ray and DSC analysis. The amount of drug going into solution from the complex was not significantly affected by the pH of the medium (in the range 1.8–6.8), while it was increased by increasing ionic strength.

Effect of α-trinositol on carrageenan-induced rat paw edema and lowering of interstitial fluid pressure

α-Trinositol attenuates edema formation and capillary albumin extravasation and lowering of interstitial fluid pressure ( P if) in several acute inflammatory reactions in rat skin or trachea. The lowering of P if is an important driving force required to explain the rapid edema formation in acute inflammatory reactions. The lowering of P if and edema formation are attenuated by α-trinositol, which is suggested to act on the cellular adhesion receptor for extracellular matrix components. This would represent a novel therapeutic strategy for acute inflammation. To further clarify the mechanisms behind the anti-inflammatory effects of α-trinositol, the effects of pre- and post-treatment with α-trinositol on edema formation and lowering of P if were studied after subdermal injection of carrageenan in the rat. The experiments measuring P if showed that the lowering of P if induced by carrageenan was abolished by 10 mg α-trinositol when administered either prior to or after injection of 5 μl 1% (w/v) lambda carrageenan in the dorsum of the paw. Edema formation after injection of lambda carrageenan (100 μl, 1.5% w/v) into the foot pad was studied in a separate series. In control animals receiving saline vehicle, the volume of the paw injected with carrageenan increased by approximately 30% after 3–4 h. The only significant effect of infusion of 20 mg kg −1 h −1 α-trinositol was a reduction of edema to approximately 20% when treatment was started 1 h before carrageenan injection. Therefore, the plasma concentration of α-trinositol must already be high when carrageenan is injected in order to prevent edema in the late phase. In conclusion, the present results indicate that the mechanisms involved in the lowering of P if in the early phase of edema development are different from those responsible for the manifest edema measured 3–4 h after carrageenan.

Plant products as topical microbicide candidates: assessment of in vitro and in vivo activity against herpes simplex virus type 2

There is considerable interest in developing topical microbicides; products to be used intravaginally by women for protection against sexually transmitted diseases. Many compounds derived from plants have been shown to have antimicrobial properties. We examined 19 such compounds in vitro by plaque reduction assay to determine their activity against a common sexually transmitted pathogen, herpes simplex virus type 2. Compounds with an ED 50≤7.0 mg/ml were tested for efficacy in vivo. Four compounds, carrageenan lambda type IV, cineole, curcumin, and eugenol, provided significant protection ( P<0.05) in a mouse model of intravaginal HSV-2 challenge. Eugenol, which provided the greatest protection in mice was also evaluated using the guinea pig model of genital HSV-2 infection where it also demonstrated significant protection. Based on these results, several plant-derived compounds appear to warrant further evaluation as potential microbicides.

Degradation of Basement Membrane by Prostate Tumor Heparanase

Background.The degradation of basement membrane (BM) by cancer is an important event that characterizes invasive biological behavior. A component of BM is heparan sulfate proteoglycan (HSPG). The glycanase(s) that degrade HSPG in BM are not yet isolated. We recently identified HSPG-degrading activity (PC-3M heparanase) in the conditioned media (CM) of malignant prostate carcinoma cells (PC-3M and LNCaP C4-2). Antibodies (Abs) to a recently isolated heparanase from human platelets (CTAP-III), cross-react with PC-3M heparanase although they differ in size; under reduced conditions PC-3M heparanase is 60 kDa whereas CTAP-III is 10 kDa by polyacrylamide gel electrophoresis. PC-3M heparanase therefore shares homology with CTAP-III. The purpose of this study was to test the inhibition of PC-3M heparanase by Abs specific to the N- and C-terminals of CTAP-III.Materials and methods.CM from PC-3M and LNCaP C4-2 cells were tested for heparanase activity. Each reaction contained substrate as [3H]glucosamine-labeled HSPG (>50 kDa) from the BM of the EHS tumor, CM from PC-3M or LNCaP C4-2 cells, and inhibitor or buffer (negative control). Protease inhibitors were present throughout. After incubation for 3–20 h at 37°C and pH 5.8, the reaction was stopped with 0.2% SDS. Each reaction mixture was centrifuged in an Ultrafree-MC 30,000 NMWL filter unit (Millipore) and radioactivity in the filtrate counted by scintillation counting.Results.For both cell lines, there was a linear relationship between the amount (μg) of CM and degradation of HSPG. Degradation was inhibited by 54.1% (mean) using carrageenan lambda (10 μg/ml), a nonspecific glycanase inhibitor (P< 0.05 by ANOVA). Ab to the N-terminus of CTAP-III (anti-Hep A) reduced degradation by 10–50% (mean 31.1%) and to the C-terminus (anti-Hep C) by 38.8–64.3% (mean 51.1%) (P< 0.003 by ANOVA).Conclusions.The degradation of HSPG by malignant prostate cancer cell lines is inhibited by both a nonspecific glycanase inhibitor, and specific Abs to a homologous platelet heparanase. Based upon molecular weight, PC-3M heparanase is different from platelet heparanase and degrades BM.

Effect of peripheral nerve injury on cGMP and nitric oxide synthase levels in rat dorsal root ganglia: time course and coexistence.

Using the indirect immunofluorescence method, the distribution of cyclic GMP (cGMP) and nitric oxide synthase (NOS) was investigated in lumbar 5 dorsal root ganglia (DRGs) of untreated rats 1, 3 and 7 days following sciatic nerve section (axotomy). Untreated and axotomized (7 days) rats were also studied after perfusion with the NO donor sodium nitroprusside (SNP). Moreover, rats were injected with carrageenan lambda into the unilateral hindpaw and studied after 6 h, 1 day or 2 days. An increase in the number of cGMP-positive satellite cell profiles was found in axotomized DRGs at 3 days with lower numbers after 7 days. In contrast, no change in cGMP-like immunoreactivity (LI) in satellite cell profiles was detected 1 day after axotomy or 6h, 1 day or 2 days after inflammation, as compared to controls. Axotomy induced a marked increase in the percentage of NOS-immunoreactive (IR) neuron profiles in the ipsilateral DRGs as follows: 3.0% at 1 day, 15% at 3 days and 25% at 7 days, whereas no significant change was found in the expression of NOS-LI in the inflamed DRGs as compared to untreated DRGs. Between 15 and 20% of all NOS-positive neuron profiles were surrounded by, or in partial contact with, cGMP-IR satellite cells in controls 1 and 3 days after axotomy, whereas the corresponding figure was around 5% after 7 days. After SNP perfusion 60-70% of all DRG neuron profiles were partly or totally associated with cGMP-positive satellite cell profiles, with no significant difference between untreated and axotomized ganglia. The nerve injury-induced, parallel upregulation of NOS in DRG neurons and cGMP in satellite cells in the initial phase after axotomy suggests an involvement of NO as a signalling molecule between neurons and satellite cells in DRGs, especially after peripheral nerve injury, perhaps exerting a survival effect as recently proposed by Thippeswamy and Morris (1997).

Antinociception by adenosine analogs and inhibitors of adenosine metabolism in an inflammatory thermal hyperalgesia model in the rat

The present study examined the spinal antinociceptive effects of adenosine analogs and inhibitors of adenosine kinase and adenosine deaminase in the carrageenan-induced thermal hyperalgesia model in the rat. The possible enhancement of the antinociceptive effects of adenosine kinase inhibitors by an adenosine deaminase inhibitor also was investigated. Unilateral hindpaw inflammation was induced by an intraplantar injection of lambda carrageenan (2 mg/100 μl), which consistently produced significant paw swelling and thermal hyperalgesia. Drugs were administered intrathecally, either by acute percutaneous lumbar puncture (individual agents and combinations) or via an intrathecal catheter surgically implanted 7–10 days prior to drug testing (antagonist experiments). N 6-cyclohexyladenosine (CHA; adenosine A 1 receptor agonist; 0.01–1 nmol), 2-[ p-(2-carboxyethyl)phenylethylamino]-5′- N-ethylcarboxamidoadenosine (CGS21680; adenosine A 2A receptor agonist; 0.1–10 nmol), 5′-amino-5′-deoxyadenosine (NH 2dAdo; adenosine kinase inhibitor; 10–300 nmol), and 5-iodotubercidin (ITU; adenosine kinase inhibitor; 0.1–100 nmol) produced, to varying extents, dose-dependent antinociception. No analgesia was seen following injection of 2′-deoxycoformycin (dCF; an adenosine deaminase inhibitor; 100–300 nmol). Reversal of drug effects by caffeine (non-selective adenosine A 1/A 2 receptor antagonist; 515 nmol) confirmed the involvement of the adenosine receptor, while antagonism by 8-cyclopentyl-1,3-dimethylxanthine (CPT; adenosine A 1 receptor antagonist; 242 nmol), but not 3,7-dimethyl-1-propargylxanthine (DMPX; adenosine A 2A receptor antagonist; 242 nmol), evidenced an adenosine A 1 receptor mediated spinal antinociception by NH 2dAdo. dCF (100 nmol), which was inactive by itself, enhanced the effects of 10 nmol and 30 nmol NH 2dAdo. Enhancement of the antinociceptive effect of ITU by dCF was less pronounced. None of the antinociceptive drug regimens had any effect on paw swelling. These results demonstrate that both directly and indirectly acting adenosine agents, when administered spinally, produce antinociception through activation of spinal adenosine A 1 receptors in an inflammatory model of thermal hyperalgesia. The spinal antinociceptive effects of selected adenosine kinase inhibitors can be significantly augmented when administered simultaneously with an adenosine deaminase inhibitor.

Vaginal formulations of carrageenan protect mice from herpes simplex virus infection.

The observations from the present study indicate that vaginal formulations of the sulfated polysaccharide carrageenan are highly effective in protecting mice from herpes simplex virus type 2 (HSV-2) infection. Test formulations were placed in the vaginas of progestin-treated mice prior to inoculation with HSV-2. Infection was determined by the presence of inflammation in the genital region and death. At a dose of virus that infected half of the control animals, 1% solutions of either lambda, kappa, or iota carrageenan prevented infection of almost all of the animals. Concentrations as low as 0.05% protected a large majority of the mice. At a dose of virus that infected all of the control mice, 1% solutions of carrageenans protected 85% of the inoculated mice. Other sulfated polysaccharides were less effective or showed no efficacy in preventing HSV-2 infection. These findings suggest that a vaginal formulation of carrageenan may be effective in blocking sexual transmission of HSV-2 in women.

Zidovudine potentiates local and systemic inflammatory responses in the rat.

The effect of chronic treatment with zidovudine (AZT) on the inflammatory response was examined in the rat. AZT was administered orally for 36 days. On day 35, inflammation was induced by hindpaw injection of 1% carrageenan lambda. Paw edema over a 24-hour period was used as a marker of the local inflammatory reaction. On day 36, quantification of immunoreactive T-kininogen and alpha 1-inhibitor-3 in liver and serum was used to assess the systemic inflammatory response. Albumin was selected as a protein whose concentration is modified only slightly or not at all during the acute-phase response. Animals treated with AZT transiently exhibited significantly greater (18%) paw edema 3 hours after carrageenan injection. AZT treatment alone induced a 1.8-fold increase in serum T-kininogen concentration, but it had no effect on albumin and alpha 1-inhibitor-3. In rats with inflamed paws, AZT administration led to a significant increase in liver (3.4-fold) and serum (1.8-fold) immunoreactive T-kininogen content. Dot blot analysis of total RNA isolated from liver correlated with the protein measurements. Our results indicate that chronic treatment with AZT potentiates the nonspecific local and the systemic inflammatory responses in the rat.

Long-term culture of primary rat hepatocytes on heparin- or lambda carrageenan-containing collagen gels.

The interactions of glycosaminoglycans (GAGs) with collagen are thought to be important in cell adhesion and cell differentiation. To investigate whether the interactions of GAG or sulfated polysaccharide with collagen can maintain the functions of cultured primary rat hepatocytes, GAG- or sulfated polysaccharide-containing collagen gels were reconstituted in vitro and used for culture of hepatocytes. Among the GAGs and sulfated polysaccharides examined, heparin- and lambda carrageenan-containing collagen gels were found to be able to stimulate and sustain albumin synthesis, while the other GAG- or sulfated polysaccharide-containing collagen gels had almost no effect on maintenance of albumin synthesis. In the cultures using collagen gels that contained 400 micrograms/ml heparin or 100 micrograms/ml lambda carrageenan, albumin synthesis by rat hepatocytes was prolonged to about 4 and 5 weeks, respectively, but albumin synthesis was kept up for only one week in the cultures using conventional collagen gels. These results suggest that the interactions of heparin or lambda carrageenan might be of importance for long-term maintenance of hepatocyte functions.

Gelation and flocculation of casein micelle/carrageenan mixtures

The specific attractive interaction between carrageenan and casein micelles is widely exploited in the dairy industry to tailor the texture of dairy desserts. However, in industrial practice it has been observed that the addition of carrageenan can cause casein micelles to sediment rapidly when the mixture is above the gelation temperature. To better understand this undesirable phenomenon, carrageenan/skim milk mixtures have been observed over a wide range of compositions at 65 and 25°C. Interactions occurred for iota, kappa and lambda carrageenan at both temperatures. At 65°C sedimentation was observed when the carrageenan concentration was above 0.2%. At 25°C either phase separation or gelation could occur. Depletion flocculation is suggested as a partial explanation for these observations. The effects of casein micelles on the viscoelastic properties of iota carrageenan have been measured in the absence of flocculation. Their presence decreases carrageenan s gelation concentration and increases both the gelation temperature and the elastic modulus.

Composition of carrageenan blends inferred from 13C-NMR and infrared spectroscopic analysis

Carrageenan blends mainly composed of kappa, iota and lambda carrageenan were investigated by 13C-NMR and infrared (IR) spectroscopy. 13C-NMR was shown to be a powerful tool for quantifying the kappa-iota ratio in a carrageenan blend. The technique, however, was not helpful for identifying lambda carrageenan. Consequently, IR spectroscopy was used to achieve a semi-quantitative determination of lambda carrageenan. By combining both techniques, the carrageenan composition of several commercial samples was established.

Enhanced descending modulation of nociception in rats with persistent hindpaw inflammation.

1. The role of descending brain stem modulatory systems in the development of persistent behavioral hyperalgesia and dorsal horn hyperexcitability was studied in rats with unilateral hindpaw inflammation. Inflammation was induced by intraplantar injection of complete Freund's adjuvant (CFA, 0.05 ml of an 1:1 oil/saline emulsion, 25 micrograms Mycobacterium), or lambda carrageenan (1 mg/ 0.1 ml saline). Thermal hyperalgesia was assessed by testing paw withdrawal latency (PWL) to a noxious heat stimulus. Superficial dorsal horn nociceptive (nociceptive specific, NS, and wide dynamic range, WDR) neuronal activity in the lumbar spinal cord was recorded extracellularly in chloralose-anesthetized rats. 2. Bilateral lesions of the dorsolateral funiculus (DLFX) at the T10 level were made in 13 rats, and the development of thermal hyperalgesia in these rats was compared with sham-operated or nonoperated control rats. In rats receiving a 0.05-ml CFA injection, a similar magnitude of hyperalgesia developed in the inflamed paw in DLFX (n = 7) and control (n = 8) rats. In addition, there appeared to be a contralateral hyperalgesia that was most apparent between 2 and 24 h after injection of CFA in DLFX rats. The CFA-induced contralateral effects were significantly different (P < 0.05) from the control rats at 2 and 6 h. 3. The intensity of the thermal stimulus was reduced and a low dose of carrageenan (1 mg) was injected into one hindpaw to further reveal the potentiation of hyperalgesia in DLFX rats. Throughout the 0.5- to 4-h time period after the injection of carrageenan, the PWL of the inflamed paws in DLFX rats (n = 6) was significantly shorter than that of control rats (n = 10; 2-way analysis of variance, F1,14 = 14.04, P < 0.01), suggesting the enhancement of hyperalgesia in DLFX rats. A hyperalgesia on the noninflamed paws was also more apparent in this experiment in DLFX rats, when compared with control rats. DLFX did not affect the baseline PWL of the rats. 4. A reversible spinalization was produced by application of a local anesthetic, lidocaine (2%, 0.1 ml), onto the dorsal surface of the thoracic cord (T10-12). This procedure produced thoracic spinal block that lasted for 90 min. The effects of thoracic lidocaine block on nociceptive neuronal activity were studied in 11 neurons (NS = 7, WDR = 4) in CFA-inflamed rats and 10 neurons (NS = 6, WDR = 4) in noninflamed naive rats. After the thoracic lidocaine block, rats showed increases in background activity, expansion of the receptive fields, and increased responses to noxious thermal, mechanical, and electrical stimuli. 5. Quantitative comparison revealed that the mean change in background firing rate of dorsal horn neurons was greater in inflamed [NS: 18.3 +/- 0.4 Hz, (mean +/- SE) n = 7; WDR: 10.9 +/- 0.7 Hz, n = 4] than that in noninflamed (NS: 2.3 +/- 0.3 Hz, n = 6; WDR: 3.3 +/- 0.4 Hz, n = 4) rats (P < 0.01, t-test) after thoracic lidocaine block. Thoracic saline application produced a 2.8 +/- 0.4 Hz decrease in background activity (2 NS and 2 WDR units). The expansion of the receptive fields after thoracic lidocaine block was also greater in inflamed (NS: 141 +/- 9% control, n = 6; WDR: 240 +/- 36% control, n = 4) than in noninflamed (NS: 114 +/- 9% control, n = 6; WDR: 167 +/- 21% control, n = 4) rats (P < 0.05, t-test). Thoracic saline did not produce a significant change in the receptive field size (105 +/- 9%, n = 4). The increases in responses to noxious thermal and mechanical stimuli after thoracic lidocaine block were also significantly greater in inflamed than in noninflamed rats (P < 0.01). There was no significant difference in the increase in responses to electrical stimulation of the sciatic nerve after lidocaine between inflamed and noninflamed rats.(ASTRACT TRUNCATED)

Characterization of a sterile soft-tissue inflammation model in thoroughbred horses.

This paper describes the use of subcutaneously-placed tissue chambers as a sterile soft-tissue inflammation model in Thoroughbred horses. Acute, non-immune inflammation was initiated by injecting a sterile lambda carrageenan solution into a tissue chamber. This model was used to study the temporal changes in oxygen and carbon dioxide tensions, pH, bicarbonate, protein, albumin, prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) concentrations, cell counts and differential counts in tissue fluid from inflamed tissue chambers and control chambers. Skin temperatures over control and inflamed chambers were also compared. Carrageenan-induced inflammation resulted in significant increases in tissue-fluid carbon dioxide tension, leucocyte count, albumin, and PGE2 and LTB4 concentrations. It also resulted in a significant decrease in tissue fluid pH and HCO3-concentration. Inflammation did not result in significant changes in tissue-fluid protein concentration, differential cell counts or skin temperature over the chambers. The use of this type of tissue chamber is well-suited for studying the pathophysiology of a self-contained, non-immune inflammatory process. The model described in this paper could prove to be very useful in studies of the distribution of anti-inflammatory drugs and the effects of such drugs on various aspects of the inflammatory process.

STUDIES ON THE MOLECULAR BASIS OF WORT CLARIFICATION BY COPPER FINING AGENTS (KAPPA CARRAGEENAN)

A comparison of the fining and gelation behaviour of kappa carrageenan suggested that folding of the polymer into a helical conformation is an essential element in the mechanism of copper fining action. Factors which destabilise or prevent the formation of helices result in the reduction or removal of fining action. Finning trials with kappa, iota and lambda carrageenan suggested that fining performance decreased with increasing carrageenan sulphate content. Carrageenan mediated clarification of dialysed wort preparations exhibited a specific requirement for the presence of potassium Ions. The deterioration of fining action in worts at acidic pH was attributed to failure of helix formation rather than chemical changes in the structure of the carrageenan molecule.