Influence of some lysosomotropic compounds on calcium ion desorption process from liposome membrane

The effect of a group of model lysosomotropic compounds on the process of Ca2+ ion desorption from lecithin liposome membranes was studied. The compounds studied were: hydrochlorides of fatty acids 2-dimethylaminoethyl esters (DM-n) for n = 9, 11, 13 and 15 carbon atoms in the fatty acid alkyl chain and methochloride of 2-dimethylaminoethyl laurate (DMS-11). It was found that all the compounds studied caused increased desorption with increasing concentration of the compound. Most effective was the quaternary ammonium salt, DMS-11. Moreover, it was found that the process of Ca2+ desorption from the membrane depended on pH of the medium. Compound DM-11 was more active at pH 8 than at pH 5. The action of DM-n compounds depended on the alkyl chain length, DM-11 and DM-13 being the most active. Apparently free amines penetrate the phospholipid membranes and incorporate into its hydrophobic core causing structural deformations. Hydrochlorides of fatty acids and the quaternary ammonium salt induce desorption of calcium ions mostly as a result of competitive electrostatic interactions. By quantum chemistry, PM3 method, and methods of molecular modelling we established the higher hydrophilicity of the polar head of DM-n series with respect to the polar head of the DMS-n compounds. DM-n compounds possess both acceptor and donor properties for hydrogen bonding while DMS-n are instrumental as acceptors only. It should be noted, that the results obtained in this paper for model membranes are in accordance with those for biological ones.     

Effectiveness of slow release L-DOPA/benserazide in treatment of end-of-dose akinesia in Parkinson disease

In an open label study 63 patients with idiopathic Parkinson's disease suffering from end-of-dose akinesia were switched from a treatment with a L-DOPA standard formulation to a combined therapy of L-DOPA standard in the morning and L-DOPA slow release (levodopa, benserazide, Madopar Depot) at the remaining single doses. Substitution of L-DOPA standard by L-DOPA slow release took on average 2-4 weeks. Patients were subsequently treated for 6 months. Due to a lower bioavailability of the slow release formulation--the latter is based on the "hydrodynamically balanced system" (HBS)--, the patients remained initially on their time schedule of drug intake but received a higher dose of L-DOPA slow release compared to the preceding L-DOPA standard therapy. In 20 centers 37 men and 26 women were included into the study. 27 males and 20 females completed the 6 month treatment period. Before switching, the patients received 438 +/- 213 mg a day L-DOPA standard, after conversion, the average dose was 617 +/- 323 mg L-DOPA slow release and 107 +/- 95 mg L-DOPA standard a day. Fluctuations during the day and at night which were rated according to a newly developed clinical 5-point rating scale were significantly improved by the treatment regimen from 2.8 +/- 0.9 to 1.4 +/- 1.2. Additionally, parkinsonian symptoms were significantly reduced during the ON-phase as there was a significant decrease of the Webster rating score from 12.0 +/- 4.6 to 7.1 +/- 4.0. Quality of life as measured by subjective ratings of the patients improved. The tolerability of the new formulation of L-DOPA was rated to be good in 51.1% and very good in 48.9%. The results of this open label study suggest that the combination of L-DOPA standard in the morning and L-DOPA slow release formulation at the following time points can be an efficient therapy in parkinsonian patients who suffer form L-DOPA related end-of-dose motor akinesia.     

Costimulatory molecule-deficient dendritic cell progenitors (MHC class II+, CD80dim, CD86-) prolong cardiac allograft survival in nonimmunosuppressed recipients

We have shown previously that granulocyte-macrophage colony-stimulating factor-stimulated mouse bone marrow-derived MHC class II+ dendritic cell (DC) progenitors that are deficient in cell surface expression of the costimulatory molecules B7-1 (CD80) and B7-2 (CD86) can induce alloantigen-specific T-cell anergy in vitro. To test the in vivo relevance of these findings, 2 x 10(6) B10 (H2b) mouse bone marrow-derived DC progenitors (NLDC 145+, MHC class II+, B7-1dim, B7-2-/dim) that induced T-cell hyporesponsiveness in vitro were injected systemically into normal C3H (H2k) recipients. Seven days later, the mice received heterotopic heart transplants from B10 donors. No immunosuppressive treatment was given. Median graft survival time was prolonged significantly from 9.5 to 22 days. Median graft survival time was also increased, although to a lesser extent (16.5 days), in mice that received third-party (BALB/c; H2d) DC progenitors. Ex vivo analysis of host T-cell responses to donor and third-party alloantigens 7 days after the injection of DC progenitors (the time of heart transplant) revealed minimal anti-donor mixed leukocyte reaction and cytotoxic T lymphocyte reactivity. These responses were reduced substantially compared with those of spleen cells from animals pretreated with "mature" granulocyte-macrophage colony-stimulating factor + interleukin-4-stimulated DC (MHC class IIbright, B7-1+, B7-2bright), many of which rejected their heart grafts in an accelerated fashion. Among the injected donor MHC class II+ DC progenitors that migrated to recipient secondary lymphoid tissue were cells that appeared to have up-regulated cell surface B7-1 and B7-2 molecule expression. This observation may explain, at least in part, the temporary or unstable nature of the hyporesponsiveness induced by the DC progenitors in nonimmunosuppressed recipients.     

Activation of the mouse heart adenosine 5',5"'-P1-P4-tetraphosphate receptor

We have previously demonstrated that mouse brain membrane fractions have a specific, saturable receptor for diadenylated nucleotides. Binding is specific for two adenosines, and the length of the phosphate bridge is critical, with four phosphates being optimal [Hilderman et al. (1991) J. Biol. Chem. 266, 6915-6918]. In this report, we demonstrate that adenosine 5',5"'-P1,P4-tetraphosphate (Ap4A) binding to its receptor is dependent upon an activation step that requires divalent cations and a serine protease. Monoclonal antibodies (Mabs) are identified that inhibit Ap4A binding to its membrane receptor. These antibodies recognize a 212-kDa membrane protein. However, SDS-PAGE analysis of Ap4A cross-linked to membrane fractions reveals that Ap4A is not attached to the 212-kDa peptide but to a 30-kDa polypeptide. Appearance of the 30-kDa polypeptide is dependent on the activation step, and one of the inhibitory antibodies blocks its appearance. We suggest that the protease-dependent processing step involves cleavage of the 212-kDa component with the appearance of an active 30-kDa receptor.     

Genetic basis for diabetes resistance in NOD/Wehi mice

The basis for diabetes resistance in low diabetes incidence NOD/Wehi mice was examined in a breeding study. NOD/Wehi mice were crossed with high diabetes incidence NOD/Lt mice producing F1 hybrid mice which expressed a low incidence of diabetes. To distinguish between genetic and environmental causes for diabetes resistance, these F1 mice were backcrossed to NOD/Lt mice resulting in BC1 hybrid mice which expressed an intermediate incidence of diabetes. Similar results were obtained by examining the severity of insulitis in the hybrid mice. As both the incidence of diabetes and severity of insulitis in the hybrid mice were consistent with a single dominant gene mediating diabetes resistance, an attempt to localize this gene was made. Although over 140 loci which display polymorphism amongst inbred strains were typed in both parental lines, only a single locus, D8Mit9, was found to differ. As heterozygotes at D8Mit9 were not over represented amongst 45 diabetic BC1 hybrid mice examined, it was concluded that a resistance gene was not linked to this locus.     

Double-blind randomized placebo-controlled study of homoeopathic prophylaxis of migraine

Homoeopathic remedies for migraine are widely available over the counter, statutorily offered by the national health service in the UK, and apparently popular with patients. Do they work? Sixty-three outpatients with migraine with or without aura by IHS criteria entered a 4-month randomized placebo-controlled, double-blind parallel-groups trial of individualized homoeopathic prophylaxis, the first month being baseline with all patients on placebo. Three patients (4.8%) dropped out, leaving 30 in each treatment group. There were chance differences in attack frequency and severity between the groups at baseline (attacks were more frequent but less severe in the placebo group). Both groups improved on therapy, but neither to a great extent on the primary outcome measure of attack frequency (verum: -19%; placebo: -16%). Reduction was mostly in mild attacks on placebo, more in moderate and severe attacks on homoeopathy. Few adverse events were reported. Overall, there was no significant benefit over placebo of homoeopathic treatment. The course of change differed between groups, and suggested that improvement reversed in the last month of treatment on placebo. On this evidence we cannot recommend homoeopathy for migraine prophylaxis, but cannot conclude that it is without effect.     

Early inpatient rehabilitation after elective hip and knee arthroplasty

CONTEXT: Inpatient rehabilitation after elective hip and knee arthroplasty is often necessary for patients who cannot function at home soon after surgery, but how soon after surgery inpatient rehabilitation can be initiated has not been studied. OBJECTIVE: To test the hypothesis that high-risk patients undergoing elective hip and knee arthroplasty would incur less total cost and experience more rapid functional improvement if inpatient rehabilitation began on postoperative day 3 rather than day 7, without adverse consequences to the patients. DESIGN: Randomized controlled trial conducted from 1994 to 1996. SETTING: Tertiary care center. PARTICIPANTS: A total of 86 patients undergoing elective hip or knee arthroplasty and who met the following criteria for being high risk: 70 years of age or older and living alone, 70 years of age or older with 2 or more comorbid conditions, or any age with 3 or more comorbid conditions. Of the 86 patients, 71 completed the study. INTERVENTIONS: Random assignment to begin inpatient rehabilitation on postoperative day 3 vs postoperative day 7. MAIN OUTCOME MEASURES: Total length of stay and cost from orthopedic and rehabilitation hospital admissions, functional performance in hospitals using a subset of the functional independence measure, and 4-month follow-up assessment using the RAND 36-item health survey I and the functional status index. RESULTS: Patients who completed the study and began inpatient rehabilitation on postoperative day 3 exhibited shorter mean (+/-SD) total length of stay (11.7+/-2.3 days vs 14.5+/-1.9, P<.001), lower mean (+/-SD) total cost ($25891+/-$3648 vs $27762+/-$3626, P<.03), more rapid attainment of short-term functional milestones between days 6 and 10 (36.2+/-14.4 m ambulated vs 21.4+/-13.3 m, P<.001; 4.8+/-0.8 mean transfer functional independence measure score vs 4.3+/-0.7, P<.01), and equivalent functional outcome at 4-month follow-up. CONCLUSION: These data showed that high-risk individuals were able to tolerate early intensive rehabilitation, and this intervention yielded faster attainment of short-term functional milestones in fewer days using less total cost.     

Contingent tolerance, compensatory responses, and physical dependence in diazepam-treated amygdala-kindled rats

Three groups of amygdala-kindled rats received 10 bidaily treatment trials: On each trial, the drug-before group received a diazepam (2.5 mg/kg i.p.) injection 1 hr before a convulsive stimulation, the drug-after group received a diazepam injection 1 hr after a stimulation, and the vehicle control group received a vehicle injection either 1 hr before or 1 hr after a stimulation. After treatment, only the drug-before group displayed significantly longer forelimb clonus under the influence of diazepam (that is, they displayed contingent tolerance to diazepam's anticonvulsant effect) and significantly longer forelimb clonus while drug free. Following a 14-day retention period, the rats in the drug-before group retained significant levels of contingent tolerance but did not display significant increases when tested drug free. These data suggest that compensatory responses do not play a causal role in the expression of contingent tolerance.