Bromelain as an adjunctive treatment for moderate-to-severe osteoarthritis of the knee: a randomized placebo-controlled pilot study.

BACKGROUND: Osteoarthritis (OA) of the knee is the most prevalent joint disorder. Previous studies suggest that bromelain, a pineapple extract, may be a safer alternative/adjunctive treatment for knee OA than current conventional treatment. AIM: To assess the efficacy of bromelain in treating OA of the knee. DESIGN: Randomized, double-blind placebo-controlled trial. METHODS: Subjects (n = 47) with a confirmed diagnosis of moderate to severe knee OA were randomized to 12 weeks of bromelain 800 mg/day or placebo, with a 4-week follow-up. Knee (pain, stiffness and function) and quality-of-life symptoms were reported monthly in the WOMAC and SF36 questionnaires, respectively. Adverse events were also recorded. The primary outcome measure was the change in total WOMAC score from baseline to the end of treatment at week 12. Longitudinal models were used to evaluate outcome. RESULTS: Thirty-one patients completed the trial (14 bromelain, 17 placebo). No statistically significant differences were observed between groups for the primary outcome (coefficient 11.16, p = 0.27, 95%CI -8.86 to 31.18), nor the WOMAC subscales or SF36. Both treatment groups showed clinically relevant improvement in the WOMAC disability subscale only. Adverse events were generally mild in nature. DISCUSSION: This study suggests that bromelain is not efficacious as an adjunctive treatment of moderate to severe OA, but its limitations support the need for a follow-up study.

Bromelain reduces mild acute knee pain and improves well-being in a dose-dependent fashion in an open study of otherwise healthy adults.

There is preliminary clinical evidence to support the contention that the anti-inflammatory and analgesic properties of bromelain help to reduce symptoms of osteo- and rheumatoid arthritis. However, there have been no controlled studies of its effects on joint health in healthy subjects who lack such diagnosis. The current study investigated the effects of bromelain on mild acute knee pain of less than 3 months duration in otherwise healthy adults. The study was an open, dose-ranging postal study in volunteers who had been recruited through newspaper and magazine articles. Two validated questionnaires (WOMAC knee health Index and the Psychological Well-Being Index) were completed at baseline and after one month's intervention with bromelain, randomly allocated to volunteers as either 200 mg or 400 mg per day. Seventy seven subjects completed the study. In both treatment groups, all WOMAC symptom dimension scores were significantly reduced compared with baseline, with reductions in the final battery (total symptom score) of 41 and 59% (P = 0.0001 and <0.0001) in the low and high dose groups respectively. In addition, improvements in total symptom score (P = 0.036) and the stiffness (P = 0.026) and physical function (P = 0.021) dimensions were significantly greater in the high-dose (400 mg per day) compared with the low-dose group. Compared to baseline, overall psychological well-being was significantly improved in both groups after treatment (P = 0.015 and P = 0.0003 in the low and high dose groups respectively), and again, a significant dose-response relationship was observed. We conclude that bromelain may be effective in ameliorating physical symptoms and improving general well-being in otherwise healthy adults suffering from mild knee pain in a dose-dependant manner. Double blind, placebo-controlled studies are now warranted to confirm these results.

Transplant atherosclerosis: role of phenotypic modulation of vascular smooth muscle by nitric oxide.

Occlusive accelerated atherosclerosis of coronary grafts is the predominant factor that limits longevity of heart transplant recipients. This form of vascular disease affects both the large epicardial and the smaller intramyocardial vessels, leading to characteristic clinical presentation that necessitates the use of sophisticated techniques for their accurate detection. Accelerated atherosclerosis after transplantation is a multifactorial disease with many events contributing to its progression. The initial vascular injury associated with ischemia-reperfusion appears to aggravate preexisting conditions in the donor vasculature in addition to activation of new immunological and nonimmunological mechanisms. Throughout these events, the endothelium remains a primary target of cell- and humoral-mediated injury. Changes in the vascular intima leads to alterations in vascular smooth muscle cell (VSMC) physiology, resulting in VSMC phenotypic modulation with the orchestration of a broad spectrum of growth and inflammatory reactions, which might be a healing response to vascular injury. Endogenous nitric oxide (NO) pathways regulate a multiplicity of cellular mechanisms that play a major role in determining the structure and function of the vessel wall during normal conditions and during remodeling associated with accelerated atherosclerosis. Recently identified signaling pathways, including mitogen-activated protein kinase, cGMP-dependent protein kinase, phosphatidylinositol 3-kinase, and transcriptional events in which nuclear factor kappa B and activator protein 1 take part, can be associated with NO modulation of cell cycle perturbations and phenotypic alteration of VSMC during accelerated atherosclerosis. This article reviews recent progress covering the aforementioned matters. We start by summarizing the clincal aspects and pathogenesis of accelerated atherosclerosis associated with transplantation, including clinical presentation and detection. This summary is followed by a discussion of the multiple factors of the disease process, including immunological and nonimmunolgical contributions. The next section focuses on cellular responses of the VSMCs relevant to lesion formation, with special emphasis on classical and recent paradigms of phenotypic modulation of these cells. To examine the influence of NO on VSMC phenotypic modulation and consequent lesion development, we briefly overview characteristics of NO production in the normal coronary vascular bed and the changes in endogenous NO release and activity during atherosclerosis. This overview is followed by a section covering molecular mechanisms whereby NO regulates a range of signaling pathways, transcriptional events underlying cell cycle perturbation, and phenotypic alteration of VSMC in accelerated atherosclerosis.

A redox-based mechanism for nitric oxide-induced inhibition of DNA synthesis in human vascular smooth muscle cells.

1. The current study explored potential redox mechanisms of nitric oxide (NO)-induced inhibition of DNA synthesis in cultured human and rat aortic smooth muscle cells. 2. Exposure to S-nitrosothiols, DETA-NONOate and NO itself inhibited ongoing DNA synthesis and S phase progression in a concentration-dependent manner, as measured by thymidine incorporation and flow cytometry. Inhibition by NO donors occurred by release of NO, as detected by chemiluminescence and judged by the effects of NO scavengers, haemoglobin and cPTIO. 3. Co-incubation with redox compounds, N-acetyl-L-cysteine, glutathione and L-ascorbic acid prevented NO inhibition of DNA synthesis. These observations suggest that redox agents may alternatively attenuate NO bioactivity extracellularly, interfere with intracellular actions of NO on the DNA synthesis machinery or restore DNA synthesis after established inhibition by NO. 4. Recovery of DNA synthesis after inhibition by NO was similar with and without redox agents suggesting that augmented restoration of DNA synthesis is an unlikely mechanism to explain redox regulation. 5. Study of extracellula interactions revealed that all redox agents potentiated S-nitrosothiol decomposition and NO release. 6. Examination of intracellular NO bioactivity showed that as opposed to attenuation of NO inhibition of DNA synthesis by redox agents, there was no inhibition (potentiation in the presence of ascorbic acid) of soluble guanylate cyclase (sGC) activation judged by cyclic GMP accumulation in rat cells. 7. These data provide evidence that NO-induced inhibition of ongoing DNA synthesis is sensitive to redox environment. Redox processes might protect the DNA synthesis machinery from inhibition by NO, in the setting of augmented liberation of biologically active NO from NO donors.

Metabolism of lactose-[13C]ureide and lactose-[15N,15N]ureide in normal adults consuming a diet marginally adequate in protein.

Oral lactose-ureide is resistant to human digestive enzymes, but is fermented by the colonic microflora. Nine normal adults consuming a diet which provided 36 g of protein/day were given oral doses of lactose-[(13)C]ureide and lactose-[(15)N,(15)N]ureide. The appearance on breath of (13)CO(2) derived from lactose-[(13)C]ureide was followed for 48 h. The fate of (15)N derived from lactose-[(15)N, (15)N]ureide was determined by measuring the recovery of (15)N in stools and urine in various forms. About 80% of the label given as lactose-[(13)C]ureide was recovered on the breath, and about 80% of label given as lactose-[(15)N,(15)N]ureide was not recovered in stool, indicating that 80% of the dose was completely fermented. At least 5% of the labelled urea was absorbed and excreted as the intact molecule. Of the (15)N derived from lactose-[(15)N, (15)N]ureide and available for further metabolic interaction, 67% was retained and 33% was excreted in urine. The time taken for [(15)N,(15)N]urea to appear in urine was similar for all subjects, but the appearance of either (13)CO(2) on the breath or [(15)N, (14)N]urea in urine varied. It is concluded that the hydrolysis of the sugar-urea bond may reflect oro-caecal transit time, but that other factors related to colonic bacterial metabolism determine the duration and extent of hydrolysis of urea by urease enzymes. Lactose-ureide can be used to probe the metabolic activity of the colonic microflora in normal individuals.

Differential regulation of DNA synthesis by nitric oxide and hydroxyurea in vascular smooth muscle cells.

We investigated the influence of nitrovasodilators on DNA synthesis in cultured human aortic smooth muscle cells and explored the hypothesis that nitric oxide (NO) is directly involved in mediating the inhibitory effects of hydroxyurea on DNA synthesis. Both NO and hydroxyurea inhibited ongoing DNA synthesis and S phase progression in our cells. Exogenous deoxynucleosides partially reversed this inhibition, suggesting that ribonucleotide reductase is a primary target for both NO and hydroxyurea. Nitrovasodilators inhibited DNA synthesis by releasing NO, as detected by chemiluminescence and as shown by the reversal of DNA synthesis inhibition by NO scavengers. This inhibition appears to occur via a cGMP-independent mechanism. In contrast, hydroxyurea did not produce a detectable NO signal, and NO scavengers had no influence on its inhibition of DNA synthesis, suggesting that NO does not mediate the inhibitory action of hydroxyurea in our system. Furthermore, the action of nitrovasodilators and hydroxyurea on DNA synthesis differed according to redox sensitivity. The redox agents N-acetyl-L-cysteine and ascorbate reversed NO inhibition of DNA synthesis and had no effect on DNA synthesis inhibition caused by hydroxyurea.

Urinary excretion of 5-L-oxoproline (pyroglutamic acid) is increased in normal adults consuming vegetarian or low protein diets.

A method for measuring 5-L-oxoproline in urine, which involves isolation by short-column chromatography, acid hydrolysis to glutamic acid and enzymic assay of glutamic acid, was used to measure the rate of excretion in normal adults, aged 20 to 45 y. There was no difference in the daily excretion between omnivorous males (217 micromol/d) and females (195 micromol/d). In vegetarian males, urinary 5-L-oxoproline (404 micromol/d) was significantly greater than in vegetarian females (267 micromol/d, P = 0.013). Compared with omnivorous males or females, excretion of 5-L-oxoproline was significantly greater in vegetarian males (P < 0.0001) and females (P= 0.005). When normal adults consumed a diet in which the protein content was controlled at either 4.0 or 6.2 g N/d for 5 d, there was a significant increase in urinary 5-L-oxoproline on d 5, compared with either d 1 or 4. There was a significant inverse linear relationship between the increased urinary 5-L-oxoproline on the fifth dietary day and the nitrogen content of the diet. On the basis of this relationship, when the urinary excretion of 5-L-oxoproline (320 micromol/d) for vegetarians was predicted from an estimate of their dietary intake of nitrogen, the estimate was, on average, close to the measured value (345 micromol/d). As a matter of course, vegetarians excrete more 5-L-oxoproline in urine than do omnivores, and we speculated that this difference might be accounted for by differences in dietary nitrogen and the endogenous capacity for de novo synthesis of glycine.

Analysis of the contraction of series and parallel muscles working against elastic loads.

The purpose of the present study was to analyze the manner in which series and parallel arrangements of respiratory muscles, contracting together, augment the forces and displacements applied to external elastic loads over those produced by a single muscle contracting alone. We first developed a series of mathematical expressions to describe the behavior of various arrangements of muscles contracting against elastic loads. We then compared the predictions of these equations with the results from experiments in which the forces and displacements produced by simple arrangements of muscles were measured. Both theoretical and experimental results indicate that, against high elastic loads, parallel arrangements of muscle strips produce greater forces and greater displacements than do single muscles; parallel arrangements do not, however, significantly increase the displacement or force applied to low elastic loads. Conversely, series arrangements result in greater forces and greater displacement of low loads, but are no better than single muscles when contracting against high loads. Against moderate loads parallel and series arrangements of muscles appear to be equivalent in generating forces and displacements during contraction. This analysis suggests that a major determinant of the effects of contraction of various networks of inspiratory muscles is the magnitude and character of the respiratory impedance against which these muscles must work. The primary difference between series and parallel arrangements of muscles is that muscles arranged in series are most effective against low elastic loads and muscles in parallel act most effectively against high loads.

Effect of hypoxia on diaphragm blood flow, oxygen uptake, and contractility.

Recent studies examining the effects of hypoxia on diaphragm function have reached conflicting conclusions, with some reports suggesting an adverse effect of even mild hypoxemia while others indicate that the diaphragm may be extremely resistant to hypoxic stress. Diaphragm tension was not, however, directly measured nor was diaphragm length controlled in these previous reports, and it seems possible that methodologic limitations may have been responsible for these discrepant results. The purpose of the present study was to examine the effects of graded, steady-state hypoxia on diaphragm blood flow, oxygen extraction, oxygen consumption, and contractility using an in situ canine diaphragm strip preparation that permitted direct and continuous measurement of diaphragm length, tension, and blood flow. Measurements were made with the diaphragm at rest, during normoxia (PaO2, 90 to 160 mm Hg), mild hypoxia (PaO2, 45 to 60 mm Hg), and severe hypoxia (PaO2, 25 to 35 mm Hg); measurements were made with the diaphragm at rest, during rhythmic contractions at a tension time index (TTI) of 0.05, and with contractions at a TTI of 0.15. Decreases in arterial oxygenation resulted in progressive increases in blood flow and in the fractional extraction of oxygen in both resting and contracting diaphragm strips. At all levels of activity tested, blood flow and fractional extraction increased sufficiently to keep diaphragm oxygen consumption constant despite reductions in arterial oxygen content. Diaphragm contractility, as assessed from the tension generated in response to a range of electrical stimuli (1 to 80 Hz), was unaffected by hypoxia for trials performed with the diaphragm at rest and contracting at a TTI of 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of amrinone on diaphragm blood flow.

The purpose of the present study was to examine the effect of amrinone, a drug known to augment cardiac output and dilate peripheral vascular beds, on diaphragm blood flow. Studies were performed on 12 anesthetized mechanically ventilated dogs in which strips of left costal diaphragm were developed in situ. Strip blood flow was assessed with a drop counter attached to a catheter tied into the phrenic veins' draining strips. Strip tension was measured with an isometric force transducer. Amrinone was administered as an intravenous bolus of 2 mg/kg followed by a continuous infusion of 25 micrograms.kg-1.min-1. Amrinone increased cardiac output and resting diaphragm blood flow [from 1.8 +/- 0.1 to 3.2 +/- 3 (SE) l/min and from 13 +/- 2 to 29 +/- 6 (SE) ml.100 g-1.min-1, respectively, P less than 0.001 for both comparisons]. Amrinone also increased blood flow during periods of rhythmic contraction (tension time indexes of 0.1-0.4, P less than 0.05 for comparisons of flow with and without amrinone at each tension time index) and increased the magnitude of the postcontraction hyperemia (P less than 0.02 for comparisons of hyperemic flow with and without amrinone at tension time indexes of 0.3 and 0.4). Graded occlusion of the inferior vena cava produced reductions in arterial pressure, cardiac output, and diaphragm blood flow both before and after amrinone. Both cardiac output and diaphragm blood flow were greater after amrinone, however, at all levels of blood pressure examined. These findings indicate that amrinone can override diaphragm vasoregulatory systems and augment diaphragm blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Discrimination of sound localization cues in young infants.

Infants 8 and 16 weeks old were tested in a visual fixation paradigm for the detection and use of sound localization cues. The effects of changes in both interaural intensity and interaural arrival time were assessed independently. For each trial, sounds were presented at the same time as visual displays located on both sides of the infant. The first eye movement and total looking time to each of the visual displays were noted by corneal reflection. Following a series of trials in which the apparent location of the sound was on 1 side, the apparent location was changed for a series of test trials. Neither age group responded with appropriate directional eye movements. The older infants did, however, show generally increased looking time on the test trials for both binaural cues. The 8-week-olds responded on test trials only when the interaural arrival time was changed. The data indicate that both binaural cues can be detected by 16-week-old infants although interaural arrival time was more salient in this paradigm.

Effects of unilateral hearing loss upon educational achievement.

Recent evidence suggests that children with relatively minor hearing impairments may be at a developmental disadvantage. A survey of over 42,000 students was conducted and children with unilateral hearing losses were identified on the basis of audiometric testing. A comparison of the standardized achievement test scores obtained by the unilateral hearers, using class and national norms with a sibling control group, yielded no significant differences although the hearing-impaired group scored lower on all subscales. There were sex differences observed, however, with male unilateral hearers performing significantly better than females on several subscales. Although the results indicate little educational disadvantage accompanying unilateral losses in this sample of children, in the absence of more definitive evidence, it would be prudent to consider a unilateral loss as a 'risk factor' for the production of developmental problems.

Interaction of uncharged bile salt derivatives with the ileal bile salt transport system.

Two series of uncharged conjugated bile salt derivatives, N-conjugates of ethanolamine and 3-amino-1,2-propanediol were studied for interaction with the ileal bile salt transport system. Evidence for interaction is threefold. 1) In everted gut sac experiments more material was removed from the mucosal compartment when ileal sacs were used. 2) These derivatives inhibited the in vitro transport of taurocholate. 3) In vivo intestinal perfusion demonstrated greater absorption from ileum than from jejunum. Number three demonstrates that such interactions are followed by transmucosal movement. Their uphill transport was less than taurocholate transport. The Na(+) requirement for cholyl-3-amino-1,2-propanediol interaction with the system was greater than for taurocholate. This observation is similar to that previously observed with taurodehydrocholate, which had a greater Na(+) requirement for transport than taurocholate. Therefore removal of the anionic charge, as well as distortion of steroid shape, increases the Na(+) requirement for substrate interaction with the transport system. These observations support our hypothesis that this interaction involves two recognition components; one includes the steroid moiety, the other a coulombic interaction between the anionic bile salt and a cationic membrane site. Additionally the membrane would have an anionic group to accomodate the Na(+). Both factors (steroidal and coulombic) operate for optimal substrate attachment. Simultaneously the system's affinity for Na(+) increases and active transport then proceeds.