Importance of imidazoline-preferring receptors in the cardiovascular actions of chronically administered moxonidine,rilmenidine and clonidine in conscious rabbits

OBJECTIVE: To determine the involvement of central imidazoline receptors in the cardiovascular actions of the chronically administered antihypertensive agents moxonidine, rilmenidine and clonidine. DESIGN AND METHODS: In 21 rabbits with implanted fourth-ventricular catheters, we investigated the central effects of three cumulative doses of an I(1)-imidazoline/alpha(2)-adrenoceptor antagonist, efaroxan, and of an alpha(2)-adrenoceptor antagonist, 2-methoxyidazoxan (2-MI), on the changes in blood pressure and heart rate (HR) elicited by chronic subcutaneous administration of moxonidine, rilmenidine and clonidine, after 1 and 3 weeks of treatment. A low, medium and high dose of 2-MI was matched to three doses of efaroxan, such that each produced equal reversal of the hypotension induced by fourth-ventricular alpha-methyldopa and hence produced a similar degree of alpha(2)-adrenoceptor blockade. RESULTS: Clonidine and moxonidine, at doses of 1 mg/kg per day, and rilmenidine at 5 mg/kg per day, produced sustained reductions in mean arterial pressure of 13 +/- 3, 15 +/- 2 and 13 +/- 2 mmHg, respectively over the 3-week treatment period, but did not alter HR. Central administration of efaroxan on day 9 and day 23 of treatment produced a greater increase in blood pressure than did 2-MI with all three antihypertensive agents. Blood pressure reached levels that were significantly above the original control values. By contrast, the alpha(2)-adrenoceptor antagonist 2-MI only induced a rebound blood pressure effect in clonidine- and to a lesser extent in rilmenidine-treated rabbits. Both efaroxan and 2-MI produced a similar degree of tachycardia in moxonidine-, rilmenidine- and clonidine-treated animals.(2) CONCLUSIONS: The greater effect of efaroxan compared to the alpha(2)-adrenoceptor antagonist 2-MI suggests that the hypotension induced by chronic subcutaneous administration of moxonidine, rilmenidine and clonidine is mediated predominantly via an action on central imidazoline receptors. Furthermore, all agents showed a propensity to produce rebound hypertension with imidazoline receptor blockade. However, only clonidine showed a rebound phenomenon when challenged by acute central alpha(2)-adrenoceptor blockade     

Changes in antipyrine clearance and platelet count,but not conventional liver tests,correlate with fibrotic change in chronic hepatitis C: value for predicting fibrotic progression

OBJECTIVE: We tested whether fibrotic progression in chronic hepatitis C could be predicted by liver tests, antipyrine clearance, or platelet count. METHODS: In 58 patients (6 untreated, 52 interferon-treated), a second liver biopsy was taken median 4.5 yr after first histologic diagnosis. We used receiver operating characteristic curves to determine whether changes in conventional liver tests, antipyrine clearance, or platelet count were predictive of altered hepatic fibrosis score. RESULTS: Apart from a weak association with change in ALT, conventional liver tests (albumin, bilirubin, prothrombin time) failed to correlate with changes (Delta) in hepatic fibrosis, but there were significant correlations between deltaantipyrine clearance or deltaplatelet count and deltafibrosis score (p < 0.01). As indicated by areas under the receiver operating characteristic curves, the diagnostic accuracy of deltaantipyrine clearance for fibrotic progression was 68%; for Deltaplatelet count it was 80%. With defined cut-off values (-0.05 ml/min/kg for deltaantipyrine clearance; -41 x 10(9)/L for deltaplatelet count), the negative predictive values for fibrotic progression were 85% with antipyrine clearance and 89% with platelet count. Corresponding positive predictive values were 48% and 91%, respectively. CONCLUSIONS: Changes in antipyrine clearance and platelet count are more sensitive than conventional tests for indicating fibrotic change in chronic hepatitis C. Both could be used to reliably identify those who do not have fibrotic progression, and platelet count also has a high positive predictive value for disease progression.     

Effect of pravastatin on loss of renal function in people with moderate chronic renal insufficiency and cardiovascular disease

Limited data suggest that HMG-CoA reductase inhibitors (statins) may slow loss of renal function in individuals with chronic renal insufficiency. This study was conducted to determine whether pravastatin reduced rates of loss of renal function in people with moderate chronic renal insufficiency. This was a post hoc subgroup analysis of a randomized double-blind placebo controlled trial. Data were analyzed from the CARE study (a randomized trial of pravastatin versus placebo in 4159 participants with previous myocardial infarction and total plasma cholesterol < 240 mg/dl). Participants with estimated GFR (MDRD-GFR) < 60 ml/min per 1.73 m(2) body surface area at baseline were considered to have moderate chronic renal insufficiency. Multivariate regression was used to calculate rates of decline in MDRD-GFR for individuals receiving pravastatin and placebo, controlling for prospectively determined covariates that might influence rates of renal function loss. Change in renal function could be calculated in 3384 individuals, of whom 690 (20.4%) had MDRD-GFR < 60 ml/min per 1.73 m(2) and were eligible for inclusion. Among all individuals with MDRD-GFR < 60 ml/min per 1.73 m(2)), the MDRD-GFR decline in the pravastatin group was not significantly different from that in the placebo group (0.1 ml/min per 1.73 m(2)/yr slower; 95% CI, -0.2 to 0.4; P = 0.49). However, there was a significant stepwise inverse relation between MDRD-GFR before treatment and slowing of renal function loss with pravastatin use, with more benefit in those with lower MDRD-GFR at baseline (P = 0.04). Rate of change in MDRD-GFR in the pravastatin group was 0.6 ml/min per 1.73 m(2)/yr slower than placebo (95% CI, -0.1 to 1.2; P = 0.07) in those with MDRD-GFR < 50 ml/min, and 2.5 ml/min per 1.73 m(2)/yr slower (95% CI, 1.4 to 3.6 slower; P = 0.0001) in those with MDRD-GFR < 40 ml/min per 1.73 m(2)/yr. Pravastatin also reduced rates of renal loss to a greater extent in participants with than without proteinuria at baseline (P = 0.006). It is concluded that pravastatin may slow renal function loss in individuals with moderate to severe kidney disease, especially those with proteinuria. These findings require confirmation by a large randomized trial conducted specifically in people with chronic renal insufficiency.     

Range of motion and stroke frequency differences between manual wheelchair propulsion and pushrim-activated power-assisted wheelchair propulsion

BACKGROUND/OBJECTIVE: The objective of this study was to examine the use and efficacy of a pushrim-activated power-assist wheelchair (PAPAW) in the reduction of upper extremity range of motion (ROM) and stroke frequency in manual wheelchair users. METHODS: Ten manual wheelchair users were evaluated using a repeated-measures design with and without the use of a PAPAW for maximum ROM of shoulder flexion/extension, abduction/adduction, internal/external rotation, and horizontal flexion/extension; elbow flexion/extension; wrist flexion/extension, supination/pronation, and ulnar/radial deviation; and stroke frequency. Participants propelled a Quickie 2 manual wheelchair configured as a PAPAW and their own wheelchair on a computer-controlled dynamometer at 3 different resistance levels and 2 different speeds. RESULTS: The use of the PAPAW significantly (P < 0.05) decreased shoulder flexion/extension and horizontal flexion/extension, elbow flexion/extension, and wrist flexion/extension and ulnar/radial deviation for many speed and resistance combinations. Univariate analysis revealed that stroke frequency was unaltered in all cases. CONCLUSION: These findings provide the foundation for studying the utility of the PAPAW in reducing the risk of upper limb injury and neuropathy in the manual wheelchair user population.     

Distinguishing ankle and knee articular cartilage

Degenerative changes in the tall and femoral distal cartilages of more than 2,000 tissue donors were graded based on the appearance of articular cartilage and osteophytes. In the ankle and the knee the degenerative changes increased with age; however, the rate of degeneration in the ankle was slower than in the knee. The degenerative changes in the ankle were more severe in men than in women, were predominantly bilateral, and seemed to be correlated with weight. The slower rate of change in the ankle may be caused, in part, by the biochemical and biomechanical tissue properties that distinguish ankle cartilage from that of the knee.     

Effects of estrogen plus progestin on gynecologic cancers and associated diagnostic procedures: the Women's Health Initiative randomized trial

Context  The effects of continuous combined hormone therapy on gynecologic cancers have not been investigated previously in a randomized trial setting. Objective  To determine the possible associations of estrogen plus progestin on gynecologic cancers and related diagnostic procedures. Design, Setting, and Participants  Randomized, double-blind, placebo-controlled trial of 16 608 postmenopausal women, who had not had a hysterectomy at baseline and who had been recruited from 40 US clinical centers between September 1993 and October 1998 (average follow-up, 5.6 years). Intervention  One tablet per day containing 0.625 mg of conjugated equine estrogens plus 2.5 mg of medroxyprogesterone acetate (n = 8506) or placebo (n = 8102). Main Outcome Measure  Incident invasive cancer of the ovary and endometrium. Results  In 5.6 years of follow-up, there were 32 cases of invasive ovarian cancer, 58 cases of endometrial cancer, 1 case of nonendometrial uterine cancer, 13 cases of cervical cancer, and 7 cases of other gynecologic cancers. The hazard ratio (HR) for invasive ovarian cancer in women assigned to estrogen plus progestin compared with placebo was 1.58 (95% confidence interval [CI], 0.77-3.24). The HR for endometrial cancer was 0.81 (95% CI, 0.48-1.36). No appreciable differences were found in the distributions of tumor histology, stage, or grade for either cancer site. The incidence of other gynecologic cancers was low and did not differ by randomization assignment. More women taking estrogen plus progestin required endometrial biopsies (33% vs 6%; P<.001). Conclusions  This randomized trial suggests that continuous combined estrogen plus progestin therapy may increase the risk of ovarian cancer while producing endometrial cancer rates similar to placebo. The increased burden of endometrial biopsies required to assess vaginal bleeding further limits the acceptability of this regimen. These data provide additional support for caution in the use of continuous combined hormones.      

Parent-defined target symptoms respond to risperidone in RUPP autism study: customer approach to clinical trials

OBJECTIVE: A consumer-oriented efficacy assessment in clinical trials should measure changes in chief complaint and consumer request (symptoms of most concern to patient/caregiver), which may be diluted in change scores of multisymptom scales. METHOD: In the Research Units on Pediatric Psychopharmacology (RUPP) Autism Network 8-week double-blind trial of risperidone versus placebo, the chief concerns of parents were collected at 0, 4, and 8 weeks (endpoint), in addition to standardized primary measures. Blinded clinical judges rated change from baseline to 4 and 8 weeks on a 9-point scale (1 = normalized, 5 = unchanged, 9 = disastrous); 94 participants had usable data. RESULTS: The most common symptoms identified by parents were tantrums, aggression, and hyperactivity. Interrater reliability was excellent. Mean ratings at endpoint were 2.8 +/- 1.2 on risperidone and 4.5 +/- 1.3 on placebo (p <.001). Ratings were collinear with Clinical Global Impression-Improvement and Aberrant Behavior Checklist Irritability subscale (primary dimensional measure). Effect size d was 1.4, compared to 1.2 on the Aberrant Behavior Checklist Irritability subscale. Effect sizes varied twofold by symptom category, largest for self-injury (2.11) and tantrums (1.95). CONCLUSIONS: Risperidone was superior to placebo in reducing symptoms of most concern to parents of autistic children with irritable behavior. Rating individualized participant-chosen target symptoms seems a reliable, sensitive, efficient, and consumer-friendly way to assess treatment effect and might have clinical application.     

SNAP-25 reduction in the hippocampus of patients with schizophrenia

In this study, the authors sought to replicate the findings of reduced synaptosomal associated protein 25 kDa (SNAP-25) immunoreactivity in the hippocampus of patients with schizophrenia. The authors also measured N-methyl-D-aspartate (NMDA) receptor 1 (NR1) receptor subunit to determine if glutamatergic synapses were involved with the loss of SNAP-25. We found 49% less SNAP-25 immunointensity in the schizophrenic group (n=7) compared to the control (n=8) or bipolar groups (n=4) (P=.004). There was no change in NMDA NR1 levels in the three groups. The authors confirm the previous report of less SNAP-25 immunoreactivity in the hippocampus using a different cohort of patients with schizophrenia. It also appears that NMDA NR1 was unchanged, indicating that the overall level of NMDA glutamatergic synapses in hippocampus is normal. These data add to evidence suggesting that in schizophrenia the molecular pathology of the hippocampus involves presynaptic components.     

Reducing the sexual risk behaviors of HIV+ individuals: Outcome of a randomized controlled trial

Testing behavioral interventions to increase safer sex practices of HIV+ individuals has the potential to significantly reduce the number of new infections. This study evaluated a behavioral intervention designed to reduce the sexual risk behaviors of HIV+ individuals. HIV+ individuals (N = 387) who reported engaging in unprotected sex with HIV- or partners of unknown serostatus were randomly assigned to (a) a single counseling session targeting problem areas identified by the participant in 3 possible intervention domains (i.e., condom use, negotiation, disclosure); (b) a single-session comprehensive intervention that covered all 3 intervention domains; (c) the same comprehensive intervention, plus 2 monthly booster sessions; or (d) a 3-session diet and exercise attention-control condition. The median number of unprotectedsex acts decreasedfrom 14 at baseline to6, 6, and4 at 4-, 8-, and 12-month follow-ups, respectively. A repeated measures analysis of variance revealed a significant decrease in unprotected sex acts across all groups across time. A significant Group x Time interaction revealed that the comprehensive-with-boosters group had the most unprotected sex at 8-month follow-up as compared to the other 3 groups. These findings suggest that a brief intervention can result in large reductions in HIV transmission risks among HIV+ individuals, but the relative benefit of one intervention approach over another remains unclear. Support for this work was provided, in part, by the National Institute of Mental Health (NIMH) Grant 5 R01 MH56264 (Brief Targeted Behavior Intervention for HIV+ Persons, T. L. Patterson, P.I.), NIMH Center Grant 2 P50 MH45294 (HIV Neurobehavioral Research Center, I. Grant, P.I.), and the Department of Veterans Affairs. We thank all of the project staff, in particular Duane Stanton, who participated in data collection and the conduct of the intervention.