Absorption and metabolism of antioxidative polyphenolic compounds in red wine

We have shown that drinking red wine reduces oxidation of LDL. This reduction in oxidation has been attributed to the polyphenolic compounds in red wine, but the mechanisms of absorption and metabolism of these compounds has been unclear. We therefore investigated the absorption and metabolism of polyphenols using rats to identify their active forms in biological fluids. We also investigated the effect of tartaric acid (TA), a major organic acid in wine, on the absorption of polyphenols. Our results suggested that low molecular weight polyphenols are absorbed in the intestine and metabolized to their glucuronide conjugates, which exhibit antioxidative activity in plasma, and that TA can enhance the bioavailability of wine polyphenols.

Inhibition by sigma receptor ligand, MS-377, of N-methyl- D-aspartate-induced currents in dopamine neurons of the rat ventral tegmental area

RATIONALE

MS-377 [( R)-(+)-1-(4-chlorophenyl)-3-[4-(2-methoxyethyl) piperazin-1-yl]methyl-2-pyrrolidinone L-tartrate] is a novel anti-psychotic drug candidate with high affinity for sigma receptors but devoid of binding affinity for PCP binding site of NMDA receptor/ion channel complex.

OBJECTIVES

The effects of MS-377 on NMDA receptor and/or its ion channel complex were examined to elucidate the antipsychotic properties of MS-377.

METHODS

We examined the effect of MS-377 on NMDA ( N-methyl- D-aspartate)-induced current in acutely dissociated dopamine neurons of rat ventral tegmental area (VTA) using patch clamp whole cell recording.

RESULTS

MS-377 applied in a bath inhibited the peak current evoked by NMDA applied via the U-tube method for 2 s in a concentration-dependent manner. Other sigma receptor ligands, BD-1063 (1-[2-(3,4-dichlorophenyl)ethyl]-4-methylpiperazine), NE-100 ( N, N-dipropyl-2-[4-methoxy-3-(2-phenylenoxy)-phenyl]-ethylamine monohydrochloride) and haloperidol also inhibited NMDA-induced current in a concentration-dependent manner. Interestingly, concomitant application of MS-377 with BD-1063, NE-100 or haloperidol at concentrations that had no effects on NMDA-induced current, potentiated the MS-377-induced inhibition.

CONCLUSIONS

The results suggest that MS-377, as well as other sigma receptor ligands, indirectly acts on the sigma receptor to inhibit glutaminergic transmission mediated by NMDA receptor/ion channel complex in VTA dopamine neurons, thereby inhibiting dopamine release in target VTA areas.

Can a determination of tartrate-resistant acid phosphatase predict postmenopausal loss of bone mass?

BACKGROUND

A study was carried out over a 24-month interval to determine if an initial measurement of serum tartrate-resistant acid phosphatase would be predictive of bone mass loss quantified by dual-energy X-ray absorptiometry, as total bone mineral content and total bone mineral content corrected for weight.

DESIGN

Sixty-two women were studied (at onset: mean age 59.7 +/- 8.9 years, 10.8 +/- 8.8 years since menopause; at conclusion: mean age 61.9 +/- 8.8 and 13.0 +/- 8.7 since menopause).

RESULTS

A paired Wilcoxon test showed a small, but significant, increase in weight (P < 0.05) and decrease in height (P < 0.05). Total bone mineral content and total bone mineral content corrected for weight decreased (P < 0.005 and 0.0001, respectively). Serum tartrate-resistant acid phosphatase increased (P < 0.005). Single-regression analysis showed that the per cent bone mass loss observed between the first and second body bone mineral content measurements correlated negatively with the first serum tartrate-resistant acid phosphatase determination (r = -0.62, P < 0.0001). Changes in tartrate-resistant acid phosphatase correlated negatively with changes in total bone mineral content (r = -0.79, P < 0.0001). In a multiple regression analysis of per cent change in bone mass against initially important variables such as age, years since menopause, weight, and tartrate-resistant acid phosphatase, only tartrate-resistant acid phosphatase was significant (P < 0.0001). The sensitivity and specifity of tartrate-resistant acid phosphatase for evaluating bone loss were 86% and 78%, respectively, and the area under the curve was of 0.83 (95% CI 0.71-0.95).

CONCLUSION

These results show that a simple measurement of serum tartrate-resistant acid phosphatase can help to predict the potential rate of bone mass loss in women.

[Microbial biomass affected by cadmium with the occurrence of organic acids in red soil]

Soil microbial biomass carbon and nitrogen were determined after adding fixed concentration of organic acids and changeable concentration of cadmium in pre-incubated red soil and 14-day incubation at 25 degrees C. The results show that soil microbial biomass carbon and nitrogen in the soil added with organic acids decreased with increasing concentration of cadmium. When the concentration of cadmium was higher than 25 mg.kg-1, the microbial biomass carbon and nitrogen in the soil added with low molecular weight of organic acids (oxalic acid, acetic acid, citric acid, tartaric acid) were lower than those without the addition of organic acids, indicating that low molecular weight of organic acids could increase the toxicity of cadmium. On the contrary, the microbial biomass carbon and nitrogen in the soil added with low molecular weight of organic acids were higher than those without the addition of organic acids when the concentration of cadmium was lower than 25 mg.kg-1, indicating that low molecular weight organic acids could decrease the toxicity of cadmium. The microbial biomass carbon and mitrogen in the soil containing humic acid were higher than those without the addition of organic acids, indicating that humic acid could decrease the toxicity of cadmium. However, the C:N ratio of soil microbial biomass was increased with increasing concentration of cadmium. Organic acids could increase microbial biomass carbon and nitrogen when soil was not added with cadmium.

L-Carnitine L-tartrate supplementation favorably affects markers of recovery from exercise stress

We examined the influence of L-carnitine L-tartrate (LCLT) on markers of purine catabolism, free radical formation, and muscle tissue disruption after squat exercise. With the use of a balanced, crossover design (1 wk washout), 10 resistance-trained men consumed a placebo or LCLT supplement (2 g L-carnitine/day) for 3 wk before obtaining blood samples on six consecutive days (D1 to D6). Blood was also sampled before and after a squat protocol (5 sets, 15-20 repetitions) on D2. Muscle tissue disruption at the midthigh was assessed using magnetic resonance imaging (MRI) before exercise and on D3 and D6. Exercise-induced increases in plasma markers of purine catabolism (hypoxanthine, xanthine oxidase, and serum uric acid) and circulating cytosolic proteins (myoglobin, fatty acid-binding protein, and creatine kinase) were significantly (P < or = 0.05) attenuated by LCLT. Exercise-induced increases in plasma malondialdehyde returned to resting values sooner during LCLT compared with placebo. The amount of muscle disruption from MRI scans during LCLT was 41-45% of the placebo area. These data indicate that LCLT supplementation is effective in assisting recovery from high-repetition squat exercise.

[Acid phosphatase, ACP (EC 3.1.3.2)]

Acid phosphatase (ACP) is a hydrolytic lysosomal enzyme secreted by a number of cells including blood cells as well as by the prostate, bones, liver and other tissues. Several isozymes of ACP have tissue specificity. The isozymes can be fractionated by electrophoresis into six bands. Prostatic ACP (bands 2-4) is frequently measured for the diagnosis of prostatic disease. Band 5, tartrate resistant ACP (TRACP) consists of two isoforms, bands 5a and 5b. TRACP 5b is considered to be a marker of the osteoclasts and 5a is found in Gaucher's cells, or in the leukocytes of patients with hairy cell leukemia.

A comparison of the effects on saliva output of oxybutynin chloride and tolterodine tartrate

BACKGROUND

Oxybutynin chloride and tolterodine tartrate are anticholinergic agents used to suppress involuntary bladder contractions in urinary incontinence. They act by inhibiting binding of acetylcholine to the muscarinic receptors in the detrusor muscle of the bladder. The same types of muscarinic receptors are found in the salivary glands; thus anticholinergic agents may decrease saliva production and cause dry mouth, a commonly cited reason for discontinuation of therapy.

OBJECTIVE

The primary objective of this study was to compare saliva output, which is an objective measure of dry mouth, in subjects taking immediate- or extended-release oxybutynin, tolterodine, or placebo.

METHODS

This was a single-site, single-dose, randomized, double-blind, 4-treatment, 4-period crossover study. Subjects were randomly assigned to 1 of 4 treatment sequences that included extended-release oxybutynin 10 mg, tolterodine 2 mg, immediate-release oxybutynin 5 mg, and placebo. Saliva output was measured objectively before dosing with each treatment and at 0.5, 1, 2, 3, 4, 6, 8, 10, and 12 hours after dosing.

RESULTS

Thirty-six healthy adult volunteers (22 women and 14 men) participated in the study. They ranged in age from 19 to 42 years (mean, 27 years). Thirty-one were white, 3 Asian, and 2 black. There were no significant differences in predose saliva output between the 4 study groups. With placebo, saliva output increased throughout the day. Saliva output was maintained at predose levels throughout the day with extended-release oxybutynin. Two hours after dosing with tolterodine and immediate-release oxybutynin, saliva output decreased nearly 0.5 g in specimens collected over 2 minutes. All 3 active treatments were associated with lower saliva output compared with placebo. Extended-release oxybutynin and tolterodine were similar with respect to area under the saliva concentration-time curve but were associated with significantly greater saliva output than was immediate-release oxybutynin (P < 0.01). There were no serious adverse events (AEs) in this study. AEs were similar between treatments, although the incidence of headache was higher in the active-treatment groups than with placebo.

CONCLUSIONS

Objective assessment of saliva output in healthy adult volunteers indicated that extended-release oxybutynin and tolterodine had less impact on saliva output than did conventional immediate-release oxybutynin, suggesting that they may yield lower levels of dry mouth.

Spinal delta-opioid receptors mediate suppression of systemic SNC80 on excitability of the flexor reflex in normal and inflamed rat

Due to low central nervous system (CNS) bioavailability of delta-opioid peptides, little is known about the effect of systemic administration of delta-opioid receptor ligands. The present study examined the effect of non-peptidergic delta-opioid receptor agonists, (+)-4-[(alphaR)-alpha-((2R,5R)-4-Allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide (SNC80) and (-)dibenzoyl-L-tartaric acid salt (SNC86), on the activity of alpha-motoneurons in decerebrate-spinal rats. The flexor reflex was facilitated by C-afferent conditioning inputs, shown by a decrease in mechanical threshold and increase in touch- and pinch-evoked responses. Systemic administration of SNC80 (10 micromol/kg) prevented and reversed the neuronal hyperactivity. We further examined the effect of this agonist on the hypersensitivity of the flexor reflex induced by intraplantar injection of Freund's adjuvant. SNC80 dose-dependently (1, 3, 5 and 10 micromol/kg) increased the mechanical threshold and decreased touch-, pinch- and Abeta-afferent inputs-evoked responses. Similar effects were seen with SNC86 (5 micromol/kg). Pretreatment with either naloxone (20 micromol/kg, i.p.) or (Cyclopropylmethyl)-6,7-dehydro-4,5alpha-epoxy-14beta-ethoxy-5beta-methylindolo [2',3':6',7']morphinan-3-ol hydrochloride (SH378; 5 micromol/kg, intraarterially (i.a.)), a novel selective delta-opioid receptor antagonist, completely abolished the anti-hypersensitivity effect of SNC80. The effect of SNC80 remained following intrathecal administration of mu-opioid receptor antagonist D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH(2) (CTOP; 1.5 nmol). These results indicate that systemic injection of SNC80 exerted antihypersensitivity in models of both acute and tonic nociception and these effects are mediated mainly through a spinal delta-opioid mechanism.

Racemization kinetics of meluadrine tartrate in aqueous solution

The kinetics of racemization of meluadrine tartrate in aqueous solution was investigated by HPLC, over the pH range of 1.2 to 12 at 40, 60 and 80 degrees C. The racemization was followed by measuring both the residual (R)-enantiomer and formed (S)-enantiomer of meluadrine. The pH-racemization rate profile of meluadrine showed a minimum racemization rate constant between pH 4 and 6, and the rate constant increased rapidly with decreasing pH below pH 3. In the basic region, the racemization rate constant showed a maximum at around pH 9. Four pathways of racemization of meluadrine are proposed, depending on the dissociation state of the phenolic and amino groups. The calculated racemization rate-pH profile agreed well with the observations. The values of activation energy (95-115 kJ/mol) suggest that a similar quinoid intermediate is involved throughout the pH range examined. The objective of this study is to clarify the racemization mechanism of benzylalcohol derivative with phenoric group. This study offers fundamental knowledge for the other benzylalcohol derivatives, which have similar moiety structure.

[Tartrate-sensitive and tartrate-resistant acid phosphatases in Amoeba proteus]

In free-living Amoeba proteus (strain B), acid phosphatase (AcP) was examined by disc-electrophoresis in polyacrylamide gel. The tartrate-sensitive amebian AcP was greatly inhibited by dithiothreitol and Cu2+, and only partly inhibited by sodium orthovanadate, ammonium molybdate, EDTA, disodium salt and Mg2+, Ca2+, Zn2+ and Mn2+. On the contrary, it appeared to be resistant to sulfhydryl reagents--4(hydroxymercury) benzoic acid, sodium salt and N-ethylmaleimide. Unlike the tartrate-sensitive enzyme, the tartrate-resistant AcP was greatly inhibited by EDTA and partly inhibited by dithiothreitol, Mg2+ and Cu2+ (Mn2+ > Cu2+), being activated by orthovanadate, molybdate, sulfhydryl reagents, Mg2+, Ca2+ and Zn2+. Both tartrate-sensitive and tartrate-resistant AcPs lack apparently free SH-groups necessary for their catalytic activities. Using 2-naphthyl phosphate as a substrate at pH 4.5, six AcP electromorphs were revealed in cytosol and sediment, four of these being most frequently localized in the former, and two in the latter. Two other AcP electromorphs were confined to the sediment only. Depending on the quantity of sedimented amoebae making a homogenate (0.5 or 2.0 cm3), that was added to Percoll solution, the lysosomal AcP fraction in polyacrylamide gel was represented by one or two tartrate-sensitive electromorphs. Therefore, tartrate-resistant AcP in A. proteus may be a lysosomal enzyme, while tartrate-resistant AcP may correspond to serine/threonine protein phosphatase.

Anti-inflammatory effects of a stabilized lipid extract of Perna canaliculus (Lyprinol)

A lipid-rich extract, prepared by supercritical fluid (CO2) extraction of freeze-dried stabilized NZ green-lipped mussel powder (Lyprinol) has shown significant anti-inflammatory (AI) activity when given to animals and humans. When treated p.o. with Lyprinol, Wistar and Dark Agouti rats developed neither adjuvant-induced polyarthritis or collagen(II)-induced auto-allergic arthritis. This was achieved with doses < NSAIDs, and 200 times < of other seed or fish oils. Lyprinol subfractions inhibited LTB4 biosynthesis by PMN in vitro, and PGE2 production by activated macrophages. Much of this AI activity was associated with omega-3 PUFAs and natural antioxidants [e.g. carotenoids]. In contrast to NSAIDs, Lyprinol is non-gastro toxic in disease-stressed rats at 300 mg/kg p.o., and does not affect platelet aggregation [human, rat]. Clinical studies, either controlled or randomized, have demonstrated very significant AI activity in patients with osteoarthritis (OA), rheumatoid arthritis (RA), asthma, and other inflammatory conditions. Lyprinol is a reproducible, stable source of bioactive lipids with much greater potency than plant/marine oils currently used as nutritional supplements to ameliorate signs of inflammation.

Characterization of acid phosphatase and phosphorylcholine hydrolase in adult Haemonchus contortus

An acid phosphatase (AP) and a phosphorylcholine hydrolase (PCH) were detected in excretory-secretory (ESP) products from adult Haemonchus contortus. The AP had a pH optimum of 4.5 and was inhibited by tartaric acid and sodium fluoride, but not by o-phenanthroline. The AP hydrolyzed paranitrophenol (pnp)-phosphate and to a lesser extent pnp-phenyl-phosphonate but did not hydrolyze diester substrates. Purified AP consisted of heterodimers with relative molecular weight (Mr) of 41.9 and 48.7 kDa and had a native molecular weight of 98 kDa by size-exclusion chromatography (SEC). The PCH had a pH optimum of about 9.5 and was inhibited by EDTA and o-phenanthroline but not by the specific phospholipase inhibitor D609. The specific activity of PCH in the ESP was approximately 25-fold less than that of AP. PCH also hydrolyzed 5'-thymidine monophosphate-pnp at a rate about 40% lower than pnp-phosphorylcholine but did not hydrolyze 3'-thymidine monophosphate-pnp. Partial purification of PCH suggests an Mr of 50.2 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and an Mr of 102 kDa by SEC. Both AP and PHC were secreted in vitro in a time-dependent manner and had their highest concentrations in the intestine. The results indicate that H. contortus adults secrete significant amounts of AP that might be a digestive enzyme. PCH is also an intestinal enzyme and is secreted in lesser amounts than AP. The PCH is probably not a phospholipase C but has some characteristics of a type I phosphodiesterase.

Effect of oral mexiletine on the cough response to capsaicin and tartaric acid

BACKGROUND

The effect of the orally active local anaesthetic mexiletine on the cough response to two different tussive agents, a C-fibre ending stimulator capsaicin and a chemostimulant tartaric acid, was examined in normal subjects.

METHODS

The cough threshold, defined as the lowest concentration of capsaicin (C(5)-CP) or tartaric acid (C(5)-TA) causing five or more coughs, and histamine induced bronchoconstriction were measured three hours after a single oral dose of 300 mg mexiletine or placebo in 14 normal subjects.

RESULTS

Mexiletene in a mean (SE) serum concentration of 0.99 (0. 04) microg/ml significantly increased C(5)-TA from a geometric mean (SE) of 32.0 (1.27) mg/ml with placebo to 49.9 (1.34) mg/ml, but C(5)-CP did not differ significantly between treatment with mexiletine (12.2 (1.33) microM) and placebo (14.9 (1.23) microM).

CONCLUSIONS

These results suggest that the cough response to capsaicin and tartaric acid may be mediated in part via different neural pathways.

Modulation of monocytic cell activity and virus susceptibility during differentiation into macrophages

A major component of innate immune responses relies on monocytes and macrophages, virus infection of which will pose a particular problem for immunological defense. Consequently, the monocytic cell differentiation pathway was analyzed in terms of cellular modulations therein and their relation to monocytotropic virus infection. Differentiation was characterized by down-regulation of CD14, MHC Ags, the monocytic SWC1 marker, and p53; concomitant up-regulation of the SWC9 macrophage marker, a putative porcine CD80 (detected with anti-human CD80 Ab), and acid phosphatase secretion were also characteristic. Elevated phagocytic and endocytic activities as well as endosomal/lysosomal acidification were identified as being important to the macrophage. In contrast, monocytes possessed high accessory activity. This was multifactorial, concomitantly requiring 1) high MHC Ag expression; 2) enzyme activity of esterase, peroxidase, myeloperoxidase, and 5' nucleotidase in preference to glucosidase, galactosidase, and glucuronidase; and 3) elevated capacity for spontaneous IL-1 production. Only with all parameters was efficient stimulation of Ag-specific lymphocytes possible. These results point to a continuous process during differentiation, involving inter-related characteristics linking the more accessory monocyte to the scavenger macrophage, both in vitro and in vivo. Of particular interest was how these characteristics related to monocytotropic virus infection, and how a particular virus could show a clear preference for the differentiating macrophages. Such results not only further our understanding of porcine immunology, but also provide evidence and a potential model for the determination and characterization of monocytotropic virus-host cell interactions.

Structure-activity relationships: analogues of the dicaffeoylquinic and dicaffeoyltartaric acids as potent inhibitors of human immunodeficiency virus type 1 integrase and replication

The dicaffeoylquinic acids (DCQAs) and dicaffeoyltartaric acids (DCTAs) are potent and selective inhibitors of human immunodeficiency virus type 1 (HIV-1) integrase. They also inhibit HIV-1 replication at nontoxic concentrations. Since integrase is an excellent target for anti-HIV therapy, structure-activity relationships were employed to synthesize compounds with: (1) improved potency against HIV-1 integrase, (2) improved anti-HIV effect in tissue culture, and (3) increased selectivity as indicated by low cellular toxicity. Thirty-four analogues of the DCTAs and DCQAs were synthesized and tested for cell toxicity, anti-HIV activity, and inhibition of HIV-1 integrase. Seventeen of the 34 analogues had potent activity against HIV-1 integrase ranging from 0. 07 to >10 microM. Seventeen analogues that were synthesized or purchased had no inhibitory activity against integrase at concentrations of 25 microM. Of the biologically active analogues, 7 of the 17 inhibited HIV replication at nontoxic concentrations. The most potent compounds were D-chicoric acid, meso-chicoric acid, bis(3,4-dihydroxydihydrocinnamoyl)-L-tartaric acid, digalloyl-L-tartaric acid, bis(3,4-dihydroxybenzoyl)-L-tartaric acid, dicaffeoylglyceric acid, and bis(3, 4-dihydroxyphenylacetyl)-L-tartaric acid. Anti-HIV activity of the active compounds in tissue culture ranged from 35 to 0.66 microM. Structure-activity relationships demonstrated that biscatechol moieties were absolutely required for inhibition of integrase, while at least one free carboxyl group was required for anti-HIV activity. These data demonstrate that analogues of the DCTAs and the DCQAs can be synthesized which have improved activity against HIV integrase.

Effect of permeabilizers on antibiotic sensitivity of Pseudomonas aeruginosa

Agents which had previously been shown to act as permeabilizers against Pseudomonas aeruginosa or other Gram-negative bacteria were tested to determine whether susceptibility to various antibiotics could be increased. In the absence of a permeabilizer, Ps. aeruginosa was resistant to several hydrophobic antibiotics and vancomycin, but not to gentamicin. Tartaric and gluconic acids had weak potentiating activity, whereas ethylenediamine tetraacetic acid and citric acid were more effective permeabilizers. However, sodium polyphosphate enhanced the activity of erythromycin, fucidin, novobiocin, rifampicin and methicillin; vancomycin was unaffected and the activity of gentamicin was reduced considerably.

Action potential conduction block of nerves in vitro by potassium citrate, potassium tartrate and potassium oxalate

OBJECTIVES

Potassium salts in desensitising formulations are believed to act by blocking nerve conduction. The aim of this study was to assess the ability of some organic potassium salts to block action potential conduction and to compare their effects with potassium chloride and potassium nitrate.

MATERIALS AND METHOD

Potassium citrate, oxalate or tartrate were added to Krebs' solutions to raise the potassium concentration to 8-64 mM. The test solutions were applied to rat spinal nerves in a bath while monitoring the compound action potentials evoked by electrical stimulation.

RESULTS

All potassium salts attenuated the compound action potential in a dose-dependent manner. There were no significant differences between the effects of potassium tartrate and potassium citrate solutions (p>0.1) which caused significantly greater compound action potential attenuation than the same concentrations of potassium oxalate (p<0.05). On the basis of the potassium ion concentration required to cause 50% attenuation of the compound nerve action potential, the relative potencies of the potassium salts were: citrate = tartrate> oxalate>chloride =nitrate.

CONCLUSION

Potassium citrate and potassium tartrate were more effective than other potassium salts in blocking nerve conduction and may be more effective dentinal desensitising agents.

Association of matrix acid and alkaline phosphatases with mineralization of cartilage and endochondral bone

The activities of acid and alkaline phosphatases were localized by enzyme histochemistry in the chondroepiphyses of 5 week old rabbits. Using paraformaldehyde-lysine-periodate as fixative, the activity of acid phosphatase was particularly well preserved and could be demonstrated not only in osteoclasts, but also in chondrocytes as well as in the cartilage and early endochondral matrices. The acid phosphatase in the chondrocytes and the matrix was tartrate-resistant, but inhibited by 2 mM sodium fluoride, whereas for osteoclasts 50-100 mM sodium fluoride were required for inhibition. Simultaneous localisation of both acid and alkaline phosphatase activities was possible in tissue that had been fixed in 85% ethanol and processed immediately. In the growth plates of the secondary ossification centre and the physis, there was a sequential localisation of the two phosphatases associated with chondrocyte maturation. The matrix surrounding immature epiphyseal chondrocytes or resting/proliferating growth plate chondrocytes contained weak acid phosphatase activity. Maturing chondrocytes were positive for alkaline phosphatase which spread to the matrix in the pre-mineralizing zone, in a pattern that was consistent with the known location of matrix vesicles. The region of strong alkaline phosphatase activity was the precise region where acid phosphatase activity was reduced. With the onset of cartilage calcification, alkaline phosphatase activity disappeared, but strong acid phosphatase activity was found in close association with the early mineral deposition. Acid phosphatase activity was also present in the matrix of the endochondral bone, but was only found in early spicules which had recently mineralised. The results suggest that alkaline phosphatase activity is required in preparation of mineralization, whereas acid phosphatase activity might have a contributory role during the early progression of mineral formation.

Clinical usefulness of serum tartrate-resistant fluoride-sensitive acid phosphatase activity in evaluating bone turnover

This study was carried out to evaluate the clinical validity and usefulness of serum tartrate-resistant fluoride-sensitive acid phosphatase (TrFsACP) activity using 2,6-dichloro-4-acetylphenyl phosphate as substrate at pH 6.2 in metabolic bone diseases. The mean Z-scores of TrFsACP activity in patients on hemodialysis were higher than in healthy subjects (male: 2.04+/-1.98, n = 49, P < .05; female: 1.49+/-2.43, n = 39, P < .05) and increased with duration of hemodialysis (r = .516, P < .01). Bone alkaline phosphatase also was found to be significantly higher in hemodialysis patients (male: 0.93+/-1.49, P < .05; female: 1.66+/-2.42, P < .05) compared with normal subjects: but had lower correlation with duration of hemodialysis than TrFsACP (r = .277, P < .05). Ulcerative colitis (1.37+/-2.21, n = 15) in males showed a significantly higher Z-score of TrFsACP compared with control subjects (P < .05). The relationship of TrFsACP activity and ultrasound findings (stiffness; speed of sound [SOS]; broadband ultra sound attenuation [BUA]) in healthy women aged 30-75 years (n = 95) were inversely and significantly correlated with stiffness (r = -.465, P < .01 ), SOS (r = -.484, P < .01), and BUA (r = -.366, P < .01), but were age dependent. TrFsACP activity significantly correlated with stiffness (r = -.521, P < .05) and SOS (r = -.527, P < .05) only in the age group of 46-55 years. BUA (r = -.313, P > .05) did not correlate significantly in any subject in the present study. We conclude that serum TrFsACP activity is useful in the diagnosis and monitoring of bone turnover.

Are aminoglycoside antibiotics excitotoxic?

Guinea pigs received gentamicin to induce a profound hearing loss (61 dB auditory threshold shift at 18 kHz). Concomitant administration of maleic or tartaric acid dissolved in dimethyl sulfoxide (DMSO) significantly reduced the threshold shift to < 40 dB. The results have several important implications. First, they support the hypothesis of a free-radical mechanism of gentamicin toxicity since the protective compounds are metal chelators and scavengers. Second, they caution against these and similar chemicals, commonly found in drug preparations, as vehicles in tests of aminoglycoside toxicity. For example, a recent study by others describing attenuation of aminoglycoside ototoxicity by NMDA antagonists may have been influenced by the presence of maleate, tartrate and DMSO. Third, they suggest simple antioxidants as a potentially efficient and inexpensive clinical prophylaxis of aminoglycoside-induced hearing loss.

Structural origins of L(+)-tartrate inhibition of human prostatic acid phosphatase

Acid phosphatase activity in the blood serum is usually separated into tartrate-resistant and tartrate-refractory, which is reported as the prostatic acid phosphatase level. Human prostatic acid phosphatase crystals soaked in N-propyl-L-tartramate were used to collect x-ray diffraction data to 2.9 A resolution under cryogenic conditions. Positive difference electron density, corresponding to the inhibitor, was found. The quality of the electron density maps clearly shows the orientation of the carboxylate and N-propyl-substituted amide groups. The hydroxyl group attached to C3 forms two crucial hydrogen bonds with Arg-79 and His-257. Previous crystallographic studies compiled on the tartrate-rat prostatic acid phosphatase binary complex (Lindqvist, Y., Schneider, G., and Vihko, P. (1993) J. Biol. Chem. 268, 20744-20746) erroneously positioned D-tartrate into the active site. Modeling studies have shown that the C3 hydroxyl group on the D(-)-stereoisomer of tartrate, which does not significantly inhibit prostatic acid phosphatase, does not form strong hydrogen bonds with Arg-79 or His-257. The structure of human prostatic acid phosphatase, noncovalently bound in N-propyl-L-tartramate, is used to develop inhibitors with higher specificity and potency than L(+)-tartrate.

The glycosylphosphatidylinositol-anchored phosphatase from Spirodela oligorrhiza is a purple acid phosphatase

We recently presented clear evidence that the major low-phosphate-inducible phosphatase of the duckweed Spirodela oligorrhiza is a glycosylphosphatidylinositol (GPI)-anchored protein, and, to our knowledge, is the first described from higher plants (N. Morita, H. Nakazato, H. Okuyama, Y. Kim, G.A. Thompson, Jr. [1996] Biochim Biophys Acta 1290: 53-62). In this report the purified 57-kD phosphatase is shown to be a purple metalloenzyme containing Fe and Mn atoms and having an absorption maximum at 556 nm. The phosphatase activity was only slightly inhibited by tartrate, as expected for a purple acid phosphatase (PAP). Furthermore, the protein cross-reacted with an anti-Arabidopsis PAP antibody on immunoblots. The N-terminal amino acid sequence of the phosphatase was very similar to those of Arabidopsis, red kidney bean (Phaseolus vulgaris), and soybean (Glycine max) PAP. Extracts of S. oligorrhiza plants incubated with the GPI-specific precursor [3H]ethanolamine were treated with antibodies raised against the purified S. oligorrhiza phosphatase. Radioactivity from the resulting immunoprecipitates was specifically associated with a 57-kD band on sodium dodecyl sulfate-polyacrylamide gels. These results, together with previous findings, strongly indicate that the GPI-anchored phosphatase of S. oligorrhiza is a PAP.