Randomised clinical trial: dried plums (prunes) vs. psyllium for constipation.

BACKGROUND: Treatment of chronic constipation remains challenging with 50% of patients dissatisfied with current therapy. There is an unmet need for natural and safe alternatives. Dried plums (prunes) have been used traditionally for constipation but their efficacy is not known. Aim To assess and compare the effects of dried plums and psyllium in patients with chronic constipation. METHODS: Subjects were enrolled in an 8-week, single-blind, randomised cross-over study. Subjects received either dried plums (50 g b.d., fibre=6 gm/day) or psyllium (11 g b.d., fibre=6 gm/day) for 3 weeks each, in a crossover trial with a 1-week washout period. Subjects maintained a daily symptom and stool diary. Assessments included number of complete spontaneous bowel movements per week, global relief of constipation, stool consistency, straining, tolerability and taste. RESULTS: Forty constipated subjects (m/f=3/37, mean age=38 years) participated. The number of complete spontaneous bowel movements per week (primary outcome measure) and stool consistency scores improved significantly (P<0.05) with dried plums when compared to psyllium. Straining and global constipation symptoms did not differ significantly between treatments (P=N.S.). Dried plums and psyllium were rated as equally palatable and both were safe and well tolerated. CONCLUSION: Dried plums are safe, palatable and more effective than psyllium for the treatment of mild to moderate constipation, and should be considered as a first line therapy.

Norepinephrine enhances adhesion of HIV-1-infected leukocytes to cardiac microvascular endothelial cells.

Recent reports have indicated that norepinephrine (NE) enhances HIV replication in infected monocytes and promotes increased expression of select matrix metalloproteinases associated with dilated cardiomyopathy (DCM) in vitro in co-cultures of HIV-infected leukocytes and human cardiac microvascular endothelial cells (HMVEC-C). The influence of NE on HIV infection and leukocyte-endothelial interactions suggests a pathogenic role in AIDS-related cardiovascular disease. This study examined the effects of norepinephrine (NE) and HIV-1 infection on leukocyte adhesion to HMVEC-C. Both flow and static conditions were examined and the expression of selected adhesion molecules and cytokines were monitored in parallel. NE pretreatment resulted in a detectable, dose-dependent increase of leukocyte-endothelial adhesion (LEA) with both HIV-1-infected and -uninfected peripheral blood mononuclear cells (PBMCs) relative to media controls after 48 hr in co-culture with HMVEC-C in vitro. However, the combination of NE plus HIV infection resulted in a significant (P < 0.0001) 18-fold increase in LEA over uninfected media controls. Increased levels in both cell-associated and -soluble ICAM-1 and E-Selectin but not VCAM-1 correlated with increased LEA and with HIV-1 infection or NE pretreatment. Blocking antibodies specific for ICAM-1 or E-Selectin inhibited HIV-NE-induced LEA. These data suggest a model in which NE primes HIV-1-infected leukocytes for enhanced adhesion and localization in HMVEC-C where they can initiate and participate in vascular injury associated with AIDS-related cardiomyopathy.

Effects of morphine on T-cell recirculation in rhesus monkeys.

A 2-yr study on effects of morphine on lymphocyte circulation in rhesus monkeys (Macaca mulatta) showed that, over time, a well-maintained morphine-dependency caused biphasic depressive effects on circulating lymphocyte levels. Depression of T cell circulation by opiates actually was a relative effect. Morphine exposure basically stabilized T cell circulation in the context of concurrent increases in controls. Biphasic effects of morphine were attributable to distinctions in circulation kinetics of CD4+/CD62L (+ & -) T cells. That is, levels of CD4+/CD62L+ T cells were selectively depressed by opiates through the first 32wk after initiation of drug, and levels of CD4+/CD62L- T cells were selectively depressed thereafter. Regression analyses also showed that morphine stabilized lymphocyte recirculation. Circulating levels of resting and activated-memory types of T cells were positively correlated in opiate-exposed monkeys during the first 32wk after opiate exposure--an effect not seen with control monkeys. Considerations of changes in the types of experimental stressors extant during the study suggested that temporally differential effects of opiates on T cell recirculation were connected with changes in the stress environment and the ability of morphine to modulate these changes. Thus, morphine, and by inference the endogenous opioid system, are involved in homeostasis of lymphocyte recirculation, probably through effects on central mediation of the stress axis.

The morphine-binding site on human activated T-cells is not related to the mu opioid receptor.

Mitogen activation of human T-lymphocytes induces a morphine-binding site. Morphine binding is displaceable by beta-endorphin (1--31) and (--)-naloxone but not DAMGO. This site is not stereoselective for (--)-morphine. T-lymphocytes, expressing this binding site, were assayed by reverse-transcription polymerase chain reaction (RT-PCR) for expression of hMOR-1 mRNA. Several primer sets were used and each assay compared with cells known to express human or mouse MOR-1 mRNA. Neither hMOR-1 nor any homologous receptor was detected in human T-lymphocytes. Therefore, the morphine-binding site on mitogen-activated T-lymphocytes is unlikely to be closely related to hMOR-1.

Effects of norepinephrine, HIV type 1 infection, and leukocyte interactions with endothelial cells on the expression of matrix metalloproteinases.

The expression of matrix metalloproteinases (MMPs) associated with AIDS-related cardiomypathies and cocaine abuse was examined in an in vitro coculture model. Human peripheral blood mononuclear cells (PBMCs), HIV infected or uninfected, were placed in coculture with primary human cardiac microvascular endothelial cells (HMVEC-C) in the presence or absence of the cocaine-inducible catecholamine norepinephrine (NE). Culture supernatants were assayed for MMP-1, -2, -3, -7, -9, and -13, and for tissue inhibitor of metalloproteinase 1 (TIMP-1) and TIMP-2, by enzyme-linked immunosorbent assay. Low levels of constitutively expressed MMP-1 and -2 were detected in individual cultures of HMVEC-C and PBMCs. NE did not induce MMP or TIMP expression by HMVEC-C and caused modest increases (3- to 4-fold) in MMP-1 and -2 by uninfected PBMCs. Increased levels of NE-induced MMP-1 (5-fold) and MMP -2 (15-fold) were detected in cocultures of HMVEC-C and uninfected PBMCs. HIV infection enhanced MMP-1 (46-fold) and MMP-2 (48-fold) and active MMP-7 (33-fold) and MMP-9 (50-fold) by PBMCs. Coculture of HIV-infected PBMCs with HMVEC-C increased MMP-1 (110-fold) and MMP-2 (307-fold) but not active MMP-7 and -9. The combination of NE, HIV infection, and coculture increased MMP-1 (126-fold) and MMP-2 (467-fold), and active MMP-7 (65-fold) and MMP-9 (75-fold). MMP-3 or-13 was not detected in any of the treatment groups and TIMP-1 and -2 appeared inversely proportional to the observed levels of MMPs. These results suggest that HIV infection, NE, and leukocyte endothelial interactions demonstrate separate and overlapping cooperative effects on the regulation of expression of TIMPs and MMPs associated with AIDS-related cardiomyopathies.

Opiates as potential cofactors in progression of HIV-1 infections to AIDS.

Because of the widely documented association of AIDS with opiate abuse, there is considerable interest in knowing whether opiates alter progression of HIV-1 infections to AIDS. The main reason for this interest is that opiates and opiate-abuse have been shown to have broad influence on immune processes as well as in vitro expressions of HIV-1. This article reviews literature defining the connection between opiate use and AIDS. Basic understanding of the effects of opiates on immune process and HIV-1 infection, especially as derived from study of a monkey model of AIDS, are discussed as well as epidemiological data regarding the connection between chronic injected drug abuse and AIDS, in the context of current knowledge about the HIV-1 infectious process and AIDS pathogenesis. Theoretically, there is ample reason to suspect that opiates are involved in progression of HIV-1 infections to AIDS. To date, however, epidemiological approaches have been unable to link decline in CD4 T-cell counts, as a marker of AIDS progression, with opiate use--although other indices of AIDS progression have yet to be thoroughly evaluated in this regard. Also, the impact of opiate use and abuse on opportunistic infections occurring prior to or concurrent with HIV-1 infection has not been closely scrutinized. Interestingly, despite considerable evidence delineating the potential of opiates to exacerbate HIV-1 infections, there is suggestive evidence from both clinical observations and basic studies that homeostatically balancing conditions of chronic, consistent opiate exposure have the potential to protect the host from progression of HIV-1 infections--a situation that may well differ from when opiate-naive subjects first experience exposure to opiates and when opiate dependency is not maintained in a consistent fashion. Taken together, therefore, information from basic studies, including most particularly studies with monkeys, and epidemiological studies, indicates that effects of opiates on progression to AIDS may be conditionally variable. There are many aspects of the drug abuse culture that have potentially offsetting consequences in terms of their potential to up- or down-regulate both HIV-1 expression and host protective responses thereto that could be relevant in this regard. In conclusion, many ambiguities are yet to be considered, and basic and epidemiological studies to be pursued before the opiate-AIDS connection is fully understood.

Cyclic adenosine 3',5'-monophosphate increases the open probability of potassium channels in activated human T cells.

In the present report we describe a cAMP-responsive K channel in activated human T cells. Single channel events were recorded using the patch-clamp technique in cell-attached-patch configuration. The channel was K selective, as determined by reversal potentials under different K gradients, and displayed voltage-independent gating. When the applied potential (Vp) was equal to zero, the conductance of the channel was 21.8 +/- 0.9 pS with 150 mM K in the electrode. Typical patches contained between two and seven channels that were relatively quiet, or silent, before agonist stimulation. Adenosine (20-30 microM) increased the average open time probability from 0.017 +/- 0.008 to 0.108 +/- 0.054 over a period of 108 s. Subsequent addition of the phosphodiesterase inhibitor Ro 20-1724 (0.5 mM) increased the probability of being in the open state to 1.155 +/- 0.407 over a period of 180 s. Channel kinetics were well described by assuming two open and two closed states. Exponential time constants for the open states were 0.51 +/- 0.06 and 4.34 +/- 0.31 ms, and closed state time constants were 0.58 +/- 0.05 and 10.1 3 +/- 2.32 ms. In addition, extracellular ATP (0.3-1.0 mM) decreased channel activity. Moreover, Rp-cAMP (0.5-1.0 mM), an antagonist that specifically blocks the ability of cAMP to bind and activate protein kinase A, failed to inhibit adenosine- and Ro 20-1724-induced increases in channel activity, implying a direct action of cAMP on channel gating.

Ethanol increases K+ conductance in human T-cells.

Ethanol increased the open probability of a K channel in cultured human T-cells. Single-channel currents were studied using the patch-clamp technique in cell-attached configuration. Ethanol increased the number of simultaneously active channels and subsequent current maxima at concentrations of 35 and 50 mM from control levels of 3.2 to 4.6 pA and 8.4 pA, respectively. Current responses were elicited by a 80 mV hyperpolarizing pulse following adjustment to the same resting potential. The channel was K-selective as determined by the reversal potentials under different Na-K gradients. When the pipette contained 155 mM K, single-channel currents had a slope conductance of 28 pS and a reversal potential of -4.3 mV. Baseline current levels often shifted in a negative direction during the application of ethanol, indicating a hyperpolarization of the membrane potential and an increase in channel activity.

A comparison of K+ channel characteristics in human T cells: perforated-patch versus whole-cell recording techniques.

Standard whole-cell records using the patch-clamp technique are obtained after rupturing the cell membrane just below the patch pipette. Inherent problems, such as the disruption of cellular architecture and the displacement of cytosol, are unavoidable. In the present report, a whole-cell recording technique which makes use of a monovalent cation ionophore, nystatin, was applied to lymphocytes. Nystatin-perforated patches allow electrical access to the cell interior while virtually blocking the diffusion of cellular constituents into the electrode. By comparing standard whole-cell and perforated-patch techniques we observed marked differences in: activation, inactivation, and deactivation kinetics; steady-state inactivation; and the conductance-voltage relationship of K+ currents in activated human T cells.

Enhanced assays detect increased chromosome damage and sister-chromatid exchanges in heroin addicts.

To refine previous studies of chromosome damage (CD) and sister-chromatid exchanges (SCE) in heroin addicts, we applied new methods developed in our laboratory to enhance detection of the cytogenetic effects of low-level radiation exposure in hospital workers. For CD analysis, we applied our thymidine-fluorodeoxyuridine-caffeine (TFC) enhancement procedure in which cells at setup receive 1 x 10(-7) M fluorodeoxyuridine to inhibit thymidylate synthetase and 4 X 10(-5) M thymidine to satisfy the induced requirement, and then in G2 receive 2.2 mM caffeine to modulate DNA repair. For SCE enhancement, caffeine treatment was initiated in G1 at 19 h before harvest. Using both standard and enhanced procedures for CD and SCE analysis, blood samples were evaluated from 20 street heroin addicts and 22 controls. Standard 2-day CD and 3-day SCE assays showed small, insignificant genotoxic increases in addicts while the enhanced CD and SCE assays showed highly significant increases. Most CD events were in the form of chromatid and chromosome breaks. There were no rings and only a few dicentrics were observed in the TFC-enhanced cultures. Although quadriradials are rare, 10 were found in addict TFC-cultures and 3 in control TFC-cultures. With the standard CD assay, the mean number of chromosome breaks per 100 cells was 0.727 for controls and 1.056 for addicts (not significant). With the TFC-enhanced assay, the same measure showed 1.483 chromosome breaks for controls and 5.143 for addicts (highly significant, ANOVA: p less than 0.0001). A highly significant difference was also observed for chromatid-type damage with the TFC-enhanced assay (chromatid breaks per 100 cells: 16.793 for controls; 48.191 for addicts). The SCE data also showed significant differences with the enhanced assay. Scoring 25 cells/condition, standard SCE cultures showed 10.892 SCE/cell for controls and 11.732 SCE/cell for addicts (not significant). With CAF enhancement there were 13.08 SCE/cell for controls and 17.05 SCE/cell for addicts (ANOVA: p less than 0.008). These findings indicate that detection of CD and SCE effects can be significantly enhanced by the use of these new procedures. The finding of greatly increased chromatid damage in the addicts with the TFC procedure suggests that at least part of the CD detected occurred in vitro and is not a product of prior in vivo damage. Therefore exposure to this drug and perhaps other environmental agents may not only leave a residue of DNA or chromosome damage but may also induce a sensitivity to further genotoxic damage that is revealed by using the enhanced procedures.