Treating disability in knee osteoarthritis with exercise therapy: a central role for self-efficacy and pain

OBJECTIVE

To examine the effects of aerobic and resistance exercise on self-efficacy beliefs in older adults with knee osteoarthritis (OA) and to determine whether self-efficacy and knee pain mediated the effects of the treatments on stair time performance and health perceptions.

METHODS

Measures of self-efficacy, knee pain, stair climbing performance, and health perceptions were collected prior to randomization and again at an 18-month followup in older adults with knee OA who were assigned to 1 of 3 treatment conditions: aerobic exercise, resistance training, or health education control. All analyses were conducted on the intention-to-treat principle.

RESULTS

Both exercise treatments increased self-efficacy for stair climbing in comparison to the health education control group. Both knee pain and self-efficacy mediated the effect of the treatments on stair climb time, whereas only knee pain mediated health perceptions.

CONCLUSIONS

The findings suggest that control beliefs and changes in physical symptoms such as knee pain are important outcomes in physical activity programs with patients who have OA of the knee. Moreover, these variables mediate the effects that such programs have on disability and health perceptions.

Adequate blood pressure control: perception and reality

Blood pressure should be controlled over 24 h to reduce or prevent cardiac hypertrophy and reduce the prevalence of sudden death, myocardial infarction and myocardial ischaemia at the time of the morning rise in blood pressure. Anti-hypertensive medication is usually given once-daily in the morning and the dose is titrated on the basis of post-dose (peak) blood pressure. This frequently leads to inadequate control prior to the next drug dose unless drugs with appropriate pharmacokinetics or pharmacodynamics are used. ACE inhibitors exhibit an E(max) plasma concentration: blood pressure response relationship, and thus short-acting ACE inhibitors can exert an effect over 24 h if titrated based on pre-dose (trough) blood pressure. However, when titrated in clinical practice on post-dose (peak) blood pressure response, doses are used that are inadequate to control blood pressure for 24 h. ACE inhibitors with appropriate pharmacokinetics such as perindopril can control blood pressure when titrated at peak provided a dose is used (4 or 8 mg) that is known to have a T:P close to 1.0. Shorter-acting ACE inhibitors frequently give inadequate control when titrated at peak. An understanding of the pharmacokinetics and pharmacodynamics of a drug, coupled with knowledge of the time the drug was taken, together with the time of blood pressure measurements, enables control to be achieved with once-daily therapy even if the drug is titrated at peak response.

Angiotensinogen T235 expression is elevated in decidual spiral arteries

Preeclampsia is associated with a common molecular variant of angiotensinogen (Met235Thr). This variant is in tight linkage disequilibrium with a mutation in the angiotensinogen promoter, G(-6)A, which leads to elevated expression in vitro. Since angiotensin II levels could play a role in atherotic changes of the uterine spiral arteries associated with preeclampsia, we investigated angiotensinogen expression in the first trimester uterus. We localized angiotensinogen transcription in uterine decidua using in situ reverse transcription PCR. We then compared decidual T235 expression levels to M235 levels in heterozygous women using an allele-specific ligation assay and a single nucleotide primer extension assay. In human decidua, angiotensinogen is expressed only in spiral artery smooth muscle cells. Heterozygous women have significantly elevated expression of the T235 allele compared to the M235 allele (P < 0.0001). These observations suggest that elevated expression of the T235 allele in decidual spiral arteries may cause first trimester atherotic changes leading to preeclampsia.

Uric acid permeability coefficient in the rat papillary collecting duct

1. While it is believed that the mammalian distal nephron is not involved in uric acid transport, this has not been directly evaluated. Nevertheless, some studies are consistent with significant distal nephron transport. 2. As uric acid transport in man may be similar to the rat, undirectional uric acid permeability was evaluated by perfusion of the isolated rat papillary collecting duct. 3. Uric acid permeability was 0.61 +/- 0.04 micron/s, which was similar to sodium permeability (0.66 +/- 0.05 micron/s) but was less than chloride permeability (0.93 +/- 0.07 micron/s) and markedly less than water permeability (4.81 +/- 0.21 micron/s). Uric acid permeability was not changed following the addition of a maximal antidiuretic concentration of arginine vasopressin (200 microU/mL), nor was it changed by altering the uric acid concentration in the perfusate and bath. 4. These results demonstrate that the papillary collecting duct is permeable to uric acid. The coefficient of transport is sufficiently low and insensitive to arginine vasopressin and uric acid concentrations to suggest that any transport that occurs is probably passive and only of minor physiological significance.

Hypertrophic osteoarthropathy in a blesbok (Damaliscus dorcas phillipsi)

A 4.5-yr-old female blesbok (Damaliscus dorcas phillipsi) was radiographed following the appearance of lameness and swelling of the right front fetlock. Radiographic interpretation at that time was osteoarthritis caused by periosteal proliferation of the right metacarpus with periarticular osteophytes surrounding the fetlock. No treatment was initiated. Gradual abdominal enlargement over several months was interpreted as evidence of pregnancy. Six months after the initial lameness complaint, the blesbok suddenly collapsed and was unable to stand. Physical examination revealed a large firm mass occupying most of the abdomen that was found to be inoperable. Following exploratory laporotomy, the blesbok was euthanized. At necropsy, the mass weighed 17 kg. It had probably caused the animal's collapse. Histologically, the bony lesions of the right metacarpus, seen radiographically at the previous examination, were consistent with hypertrophic osteoarthropathy and may have been a sequela of the intra-abdominal mass.

Compliance to exercise therapy in older participants with knee osteoarthritis: implications for treating disability

This investigation examined predictors of compliance with exercise therapy in a clinical trial involving older adults with knee osteoarthritis (OA). The study sample was partitioned into tertiles by level of compliance to determine its effect on several clinical outcome measures in the trial (i.e., knee pain, difficulty with activities of daily living, and performance-related disability). The participants (N = 439) first completed all baseline assessments and were then randomly assigned to one of three treatment conditions: health education control, aerobic exercise, or resistance exercise. The two exercise treatments involved a 3-month center-based phase and a 15-month home-based phase. Variables in five categories (i.e., demographic, fitness, health-related quality of life, performance-related disability, and prior exercise behavior) were entered as predictors of attendance and time spent exercising during each session for three different periods of time across the course of the study. Results of these analyses revealed that it was possible to explain more variance for time spent exercising (approximately 40%) during the first 3 months than for attendance (approximately 10%). Furthermore, once participants completed the first 3 months of their training, prior behavior was the strongest predictor of exercise compliance. In most cases, the regression models accounted anywhere from 26 to 46% of the variance in attendance or time spent exercising (7 of the 8 P values < 0.01). In general, demographic, fitness, psychosocial, and disability-related measures did not predict compliance with any consistency across the various phases of the trial. Analysis of the dose-response data suggest that, in the use of aerobic exercise to deter disability in older people with knee OA, consideration should be given to prescribing frequent bouts of activity (at least 3 times each week) of moderate duration (approximately 35 min).

The relationship of blood pressure to cardiac hypertrophy: experimental studies in rats

Cardiac hypertrophy is an independent predictor of morbidity and mortality. The exact relationship between blood pressure, hormones and cardiac hypertrophy is unclear. This study was undertaken to determine if intermittent elevation of blood pressure could cause left ventricular hypertrophy. Blood pressure was elevated intermittently by intraperitoneal injections of angiotensin II, noradrenalin and methoxamine. Blood pressure was acutely elevated by 60 mmHg or more for periods lasting up to 1 hour on up to 4 occasions each day. Cardiac index was measured 2 and 4 weeks after the experiment started. The cardiac index was increased by all procedures. The results were complicated by a retardation of growth in some experimental groups, meaning that the cardiac weight did not increase though the index did. In a study looking at the interaction of sodium and angiotensin II high sodium intake caused left ventricular hypertrophy and injections of angiotensin II caused further left ventricular hypertrophy. This study indicated that acute intermittent elevation of blood pressure could cause left ventricular hypertrophy and suggests that wall stress rather than 24 hour workload is the important triggering mechanism.

The effect on 24 h blood pressure control of an angiotensin converting enzyme inhibitor (perindopril) administered in the morning or at night

OBJECTIVE

To determine the clinic and ambulatory blood pressure when the same dose of perindopril (4 mg) is administered in the morning (0900 h), or at night (2100 h), in particular, to determine whether the early morning blood pressure rise, the duration of effect and the pattern of response differed.

METHODS

Twenty male patients with diastolic blood pressure 95-110 mmHg when seated and 24 h mean ambulatory diastolic blood pressure > 85 mmHg after 4 weeks' placebo were allocated randomly to be administered 4 mg perindopril at 0900 h or at 2100 h. Clinic blood pressure (with the patient seated and erect) was measured 2 and 4 weeks after the therapy had been started and ambulatory blood pressure monitoring with a SpaceLabs device was performed for 26 h during week 4. The patients then crossed over to the other time of dosage and the measurements were repeated. The study was conducted from a hospital clinic.

RESULTS

The clinic analysis concerned all 20 patients but the ambulatory analysis concerned 18 patients because the ambulatory blood pressure monitor data sets were inadequate for two patients. Compliance was high (97 +/- 3%), with a suggestion that it was better with the 0900 h dose. Clinic blood pressure (with the patient seated and erect) was lower under both regimes and the blood pressure with night-time administration of perindopril tended to be lower than that with daytime administration (P = 0.05-0.10). Twenty-four-hour mean, daytime and night-time means were lower with both doses than they were with placebo and did not differ. Both regimes reduced the early morning peak blood pressure rise and the effect tended to be greater with the 2100 h dose (P = 0.05-0.10). The 0900 h dose had an effect that persisted for > 24 h but the effect of the 2100 h dose had dissipated 18 h after the dose. There was no excessive night-time fall in blood pressure with the 2100 h dose. The trough : peak ratio with the 0900 h dose was 0.86 for systolic and 0.70 for diastolic blood pressure.

CONCLUSION

The early morning blood pressure rise is reduced more when 4 mg perindopril is administered at 2100 h. However, the 2100 h dose regime does not reduce blood pressure over 24 h whereas 24 h control is achieved with the 0900 h dose. In clinical practice the 2100 h dose would have been titrated to the next dose range in more patients. This study indicates that the response profile obtained with an angiotensin converting enzyme inhibitor cannot be transformed from one dose time to another automatically and that chronobiology has important effects on a drug's action.

A study of caloric restriction and cardiovascular aging in cynomolgus monkeys (Macaca fascicularis): a potential model for aging research

Caloric restriction has been demonstrated to retard aging processes and extend maximal life span in rodents, and is currently being evaluated in several nonhuman primate trials. We initiated a study in 32 adult cynomolgus monkeys to evaluate the effect of caloric restriction on parameters contributing to atherosclerosis extent. Following pretrial determinations, at which time a baseline measure of ad libitum (ad lib) dietary intake was assessed, animals were randomized to an ad lib fed group (control) or a caloric restriction group (30% reduction from baseline intake). The animals are being evaluated for glycated proteins, insulin, glucose, insulin sensitivity measures, and specific measures of body fat composition by CT scans (e.g., intra-abdominal fat) over specified intervals. The results from the first year of observation demonstrate a significant diet effect on body weight, and specifically intra-abdominal fat. Further, insulin sensitivity has been significantly increased after 1 year of caloric restriction compared to the ad lib fed group. These studies indicate that caloric restriction has a marked effect on a pathologic fat depot, and this change is associated significantly with an improvement in peripheral tissue insulin sensitivity.

A randomized trial comparing aerobic exercise and resistance exercise with a health education program in older adults with knee osteoarthritis. The Fitness Arthritis and Seniors Trial (FAST)

OBJECTIVE

To determine the effects of structured exercise programs on self-reported disability in older adults with knee osteoarthritis.

SETTING AND DESIGN

A randomized, single-blind clinical trial lasting 18 months conducted at 2 academic medical centers.

PARTICIPANTS

A total of 439 community-dwelling adults, aged 60 years or older, with radiographically evident knee osteoarthritis, pain, and self-reported physical disability.

INTERVENTIONS

An aerobic exercise program, a resistance exercise program, and a health education program.

MAIN OUTCOME MEASURES

The primary outcome was self-reported disability score (range, 1-5). The secondary outcomes were knee pain score (range, 1-6), performance measures of physical function, x-ray score, aerobic capacity, and knee muscle strength.

RESULTS

A total of 365 (83%) participants completed the trial. Overall compliance with the exercise prescription was 68% in the aerobic training group and 70% in the resistance training group. Postrandomization, participants in the aerobic exercise group had a 10% lower adjusted mean (+/- SE) score on the physical disability questionnaire (1.71 +/- 0.03 vs 1.90 +/- 0.04 units; P<.001), a 12% lower score on the knee pain questionnaire (2.1 +/- 0.05 vs 2.4 +/- 0.05 units; P=.001), and performed better (mean [+/- SE]) on the 6-minute walk test (1507 +/- 16 vs 1349 +/- 16 ft; P<.001), mean (+/-SE) time to climb and descend stairs (12.7 +/- 0.4 vs 13.9 +/- 0.4 seconds; P=.05), time to lift and carry 10 pounds (9.1 +/- 0.2 vs 10.0 +/- 0.1 seconds; P<.001), and mean (+/-SE) time to get in and out of a car (8.7 +/- 0.3 vs 10.6 +/- 0.3 seconds; P<.001) than the health education group. The resistance exercise group had an 8% lower score on the physical disability questionnaire (1.74 +/- 0.04 vs 1.90 +/- 0.03 units; P=.003), 8% lower pain score (2.2 +/- 0.06 vs 2.4 +/- 0.05 units; P=.02), greater distance on the 6-minute walk (1406 +/- 17 vs 1349 +/- 16 ft; P=.02), faster times on the lifting and carrying task (9.3 +/- 0.1 vs 10.0 +/- 0.16 seconds; P=.001), and the car task (9.0 +/- 0.3 vs 10.6 +/- 0.3 seconds; P=.003) than the health education group. There were no differences in x-ray scores between either exercise group and the health education group.

CONCLUSIONS

Older disabled persons with osteoarthritis of the knee had modest improvements in measures of disability, physical performance, and pain from participating in either an aerobic or a resistance exercise program. These data suggest that exercise should be prescribed as part of the treatment for knee osteoarthritis.

Symbiotic effectiveness of Rhizobium leguminosarum bv. trifolii collected from pastures in south-western Victoria

Summary. The whole-soil inoculation method was used to assess the symbiotic effectiveness of rhizobia populations in soils collected from 18 randomly-selected pastures in south-western Victoria. This was part of a larger study which described the condition of pasture within this region. Based on the shoot weights of test subterranean clover plants, cv. Mount Barker, effectiveness varied from 36 to 94% depending on the site of rhizobia collection. This range was wider than that found in an earlier survey of rhizobia effectiveness conducted nearby. WU95, the commercial inoculant for subterranean clover, was significantly more effective than 9 of the rhizobia samples. Rhizobia from 2 sites were especially poor and their effectiveness (37%) was not significantly different from the nil inoculum control (28%). Symbiotic effectiveness was not related to soil pH, available sulfur, available phosphorus, total nitrogen or mean annual rainfall for each site where rhizobia were collected. After pooling data for all sites, the shoot weights were significantly related to the proportions of plants with nodules assigned high nodulation scores. In contrast, low scores, within 1 of 6 categories, did not significantly affect shoot weight. The technique of using mean nodulation score was less capable of discriminating differences in symbiotic effectiveness, compared with assessment based on test plant weight.

The renin-angiotensin system and the heart: beyond 2000

Renin-angiotensin is both a circulatory and a local tissue system. However, in most circumstances, renin present in the heart and blood vessels is taken up from the plasma, and the kidney is the prime source of this renin. Tissues can then modulate and control the production of angiotensin II. In various organs, angiotensin II has local actions. In the heart, working through the AT1 receptor, it increases contractility and may cause cardiocyte hypertrophy. Indirectly, the heart is also very much affected by the vascular actions of angiotensin II. However, the net result on the heart is the product of an important interaction between a large number of factors. There is little doubt that an inappropriately high plasma (and tissue) level of renin, related to sodium balance, is associated with increased left ventricular hypertrophy and cardiovascular complications. The genetic approach will lead to an understanding of genomic risk factors in hypertension and may identify control systems--at present unknown--which will lead to a new approach to the prevention of cardiovascular death. It is, however, unlikely that such a factor will clearly predict an individual's prognosis, but it will, rather, identify groups at risk. Constellations of genomic interactions with multiple environment factors reduce this power. Modification of the response to angiotensin II using present treatment, or interrupting the response at more distal sites, may enable us to achieve the beneficial effects on cardiac hypertrophy without the detrimental effects.

How important is 24-hour control of blood pressure?

Control of blood pressure over the full 24-hour period is important to prevent, or allow resolution of, cardiac and vascular hypertrophy. In addition, the peak incidence of sudden death, myocardial infarction and stroke occurs at the time of the blood pressure increase associated with awakening and arising. There is at present no objective evidence that "good' 24-hour blood pressure control will improve prognosis. Once-daily therapy has created problems in hypertension management. The problem in assessing new drugs was that, in order to achieve blood pressure control before the next drug dose, excessive falls in blood pressure occurred at peak drug concentrations or excessive blood drug concentrations were produced. This led to the concept of a trough: peak ratio. This is not a unique property of a drug and if drugs have an Emax effect (i.e. the drug produces a plateau response) it is dose dependent. Interpreting a trough: peak ratio requires an understanding of the interaction between the pharmacokinetics and pharmacodynamics of a drug. The answer is to use drugs with an elimination half-life close to or greater than the dose interval (24 hours); to use drugs with an "effective' half-life close to or greater than the dose interval, which can be achieved either by modification of the pharmaceutical delivery system or by using drugs that produce a persistent effect because of physiological changes induced; or to give drugs more frequently than once a day. 24-hour blood pressure control is important and the trough: peak ratio of a drug gives a guide as to whether it can be achieved.

Evaluation and comparison of two new prostate carcinoma markers. Free-prostate specific antigen and prostate specific membrane antigen

BACKGROUND

Two new prostate cancer markers, free-prostate specific antigen (f-PSA) and prostate specific membrane antigen (PSMA) were recently introduced. This report summarizes a prospective two-year multicenter test of their diagnostic or prognostic capabilities. Total PSA was also measured.

METHODS

There were four clinical groups studied: (1) 226 individuals from a screening project undergoing ultrasound and biopsy evaluation had markers obtained: (2) 68 patients suspected of having prostate cancer and undergoing 2 or more biopsies had the markers obtained on multiple occasions: (3) 100 patients undergoing radical prostatectomy had markers obtained pre- and post-operatively: and (4) 31 patients with metastatic prostate cancer each had multiple samples for marker assay obtained over a 2-year period. In all, 465 patients had one or more samples obtained and studied.

RESULTS

Free-PSA affords little additional diagnostic advantage compared with total PSA in the screening population. The receiver operating characteristic curves for diagnostic accuracy were ranked: (1) PSA density; (2) total PSA; (3) f-PSA; and (4) PSMA, PSMA showed the best correlation with stage of the primary tumor in the screened group. In the multiple negative biopsy group, f-PSA varied from 12 to 21%. PSMA values were evaluated in all histologic categories. PSA density was > or = 0.15 in all categories. In the prostatectomy cases PSA values postoperatively were quite low in Stage II; f-PSA was of no value. Later, f-PSA was increased in association with elevated total PSA values. Mean PSMA values were above normal in all postoperative time periods except in Stage III patients at 6 months to 1 year postoperatively. PSA densities were all > or = 0.15. In patients with metastatic carcinoma, elevated PSMA values correlated best with a poor prognosis (clinical progression), as has been described.

CONCLUSIONS

These data suggest that f-PSA values do not provide additional diagnostic benefit compared with total PSA in screening populations, in the presence of suspected cancer, postprostatectomy, or in metastatic disease. PSMA is of prognostic significance, especially in the presence of metastatic disease, and correlates well with the stage of disease in cancers detected in a screened population.

Individual considerations in wound management

The following two case reports describe wound management strategies used to improve the quality of patient care

Clinical pathway effects on treatment of the alcohol withdrawal syndrome

We investigated whether initiating a clinical pathway, that incorporated the use of an alcohol withdrawal assessment scale, would decrease length of stay (LOS) for and/or amount of benzodiazepine prescribed during uncomplicated alcohol detoxification. We retrospectively reviewed alcohol detoxification admissions on an inpatient unit: 66 admissions before, 56 after, and 75 admissions 1-year after initiation of the pathway. Admissions were grouped into completers and non-completers. Comparison of group means before and after pathway implementation demonstrated a significant decrease in LOS for completers of the detoxification service from 7.35 to 4.77 days, and from 6.67 to 4.31 days for all admissions. Similarly, total benzodiazepine exposure decreased to a third of the mg amount given per admission prior to the pathway. There were no increases in the "irregular" discharge rate or complication rate. These findings suggest that a clinical pathway, with an incorporated withdrawal assessment scale, can decrease LOS and benzodiazepine prescribing on an alcohol detoxification unit.

A study of the efficacy of felodipine given once or twice daily in the management of elderly hypertensive patients

The use of medication given once daily in clinical practice may lead to inadequate control of blood pressure (BP) over 24 h because medication is frequently titrated at the time of peak effect. Twenty-three patients aged 65-84 completed a study in which they received placebo, felodipine 2.5 mg once daily, felodipine 2.5 mg 12-hourly, and felodipine 5 mg once daily in a randomized, double-blind crossover design. BP response was assessed in the clinic 24 h after medication and by 24 h ambulatory monitoring. The trough/peak ratio was defined as the fall in BP in the 23rd and 24th hour post dose divided by the fall in BP in the 3rd and 4th hour post dose. BP fell with all three regimes and the clinic BPs did not differ from each other but were lower than placebo. Peak BP responses from the ambulatory BP monitor recording were similar with each dose but a greater percentage of the effect was maintained prior to the morning dose with 2.5 mg 12 hourly and 5 mg once daily. Felodipine 2.5 mg once daily reduces BP and in some people this effect persists for 24 h. However if this dose is used BP should be measured prior to the dose of the drug to ensure that 24 h control is maintained. Felodipine 5 mg once daily and felodipine 2.5 mg b.d. were equally effective at maintaining control and there was no significant advantage in using the twice daily regime. If felodipine 5 mg once daily or higher doses are used BP can be titrated post dose with the knowledge that more than 75% of the effect will still be present prior to the next dose of the drug. Thus once daily felodipine extended release (ER) 5 mg or more can be used effectively to maintain BP control over 24 h in clinical practice. In some elderly patients felodipine ER 2.5 mg once daily is an adequate regime.

Role of social class in excess black stroke mortality

BACKGROUND AND PURPOSE

It has been suggested that a substantial proportion of the excess stroke mortality among black Americans may be attributable to relatively lower socioeconomic status (SES) in this group. In this report we provide the first quantitative estimates of the proportion of excess black stroke mortality attributable to SES for a large population-based cohort.

METHODS

We used data from the National Longitudinal Mortality Study for persons 45 years and older (73,400 white men, 87,528 white women, 6522 black men, and 8816 black women). Sex-specific proportional hazards model were used to estimate excess black stroke mortality with and without adjustment for education and income (measures of SES). The contribution of SES to the excess black stroke risk was estimated from the difference in regression coefficients for race in these models.

RESULTS

In men, low SES was associated with increased stroke mortality (P < or = .0001) and accounted for 14% to 46% of the excess black stroke risk (P < .05). However, we could find no association between SES and stroke mortality in women, and SES did not account for a significant proportion of the excess stroke mortality in black women.

CONCLUSIONS

Although SES proved to account for a statistically significant proportion of excess male black stroke mortality, overall SES explained less than one quarter of the observed excess between ages 45 and 65. In women, SES did not significantly reduce the estimated excess black stroke mortality. Although SES may be playing a role in excess black stroke mortality, a substantial proportion of the excess appears attributable to other sources, including cerebrovascular risk factors that are unrelated to SES, unmeasured lifestyle influences, social resources, and genetic factors.

Perfused Kupffer cell mass. Correlation with histology and severity of chronic liver disease

The perfused Kupffer cell mass determines sulfur colloid distribution by liver spleen scan (LSS) and is proportional to the perfused hepatocyte mass. This accounts for the correlation of sulfur colloid distribution with tests of hepatic function and raises the question of whether the LSS can be used as a quantitative test of hepatic function. The recent ability to precisely measure sulfur colloid distribution by single-photon-emission computerized tomography (SPECT) prompted us to evaluate the clinical value in 329 consecutive patients with adequate LSS and clinical information, of which 27 apparent normals and 220 patients with chronic liver disease (CLD) were included in this study. The liver-bone marrow index (LBI) indicated the distribution of counts between the liver and bone marrow. The liver-spleen index (LSI) indicated the distribution between liver and spleen adjusted for spleen size. The LBI and LSI correlated with each other (r = 0.753; P < 0.001). The arithmetic mean of LBI and LSI was defined as the severity score. Detailed clinical evaluation was available in these patients and included 109 who had liver biopsy. A severity score in 27 normals was 102 +/- 5 (mean +/- SD) with all values > 85. The severity score correlated with hepatic fibrosis (r = -0.694; P < 0.001) in 109 patients with benign liver disease who had recent biopsies and with the Child-Pugh classification (r = 0.78; P < 0.001) in 220 patients with CLD.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy and safety of controlled-release niacin in dyslipoproteinemic veterans

OBJECTIVE

To evaluate the safety and efficacy of controlled-release niacin in patients with hyperlipoproteinemia.

DESIGN

A retrospective cohort study.

SETTING

A Department of Veterans Affairs Medical Center.

PATIENTS

A consecutive sample of 969 predominantly elderly male veterans treated for dyslipoproteinemia with controlled-release niacin between October 1988 and October 1991.

MAIN OUTCOME MEASURES

Primary outcomes were lipid levels and lipoprotein cholesterol response, alternations in levels of hepatic enzymes and blood chemistry test results, and characterization of niacin-induced hepatotoxicity abstracted from the patient's medical, laboratory, and pharmacy records.

RESULTS

93% (896 of 969) of the cohort was evaluable. Patients (age, 61.7 years [9.4 years], mean [SD]) were treated for 1 to 36 months (13.0 months [9.7 months]) with an average maintenance dose of 1.67 g/d (0.8 g/d). Niacin was discontinued in 48.5% (435 of 896) of the patients primarily because of adverse effects. Poor glycemic control led to discontinuation in 40.6% (43 of 106) of the patients with diabetes mellitus. The lipoprotein response was dose-related and favorable (levels of total cholesterol, -19.1%; low-density lipoprotein cholesterol, -24.0%; high-density lipoprotein cholesterol, +5.7%; and triglycerides, -32.5%). Statistically but not clinically meaningful dose-related increases were seen in levels of liver enzymes and serum glucose (aspartate aminotransferase, +29%; alanine aminotransferase, +23%; alkaline phosphatase, +25%; and glucose, +7%; P = 0.0001). Twenty of 896 (2.2%) and 42 of 896 (4.7%) patients met biochemical criteria for probable and for possible or probable niacin-induced hepatotoxicity, respectively. Predisposing factors included high dose, alcohol use, preexisting liver disease, and concurrent oral sulfonylurea therapy.

CONCLUSIONS

Controlled-release niacin is effective in treating dyslipoproteinemia in selected middle-aged and elderly veterans, but approximately one half of patients discontinued the drug because of adverse effects or other causes including noncompliance. Niacin should be avoided in patients with hepatic dysfunction or a history of liver disease, patients with diabetes mellitus, and patients who abuse alcohol. Because controlled-release niacin seems to be more potent than crystalline niacin, product substitution without dose adjustment should be avoided.

[The kidney and hypertension]

The kidney and hypertension are critically linked. They appear to be linked particularly by the renin angiotensin system and the control of sodium balance. There are other mechanisms by which the kidney controls hypertension, but there are not as important as the above. In people with intrinsic renal disease hypertension increases the rate of deterioration and such hypertension should be treated energetically to prevent this deterioration. Long-standing chronic mild impairment of renal function leads to hypertension and vascular disease. This hypertension and vascular disease causes further deterioration of renal function, setting up a vicious cycle and an irreversible process unless measures are taken to interrupt the cycle.

[The regulation of renin synthesis]

Secretion and synthesis of renin are stimulated by the lack of angiotensin II and by a low sodium intake. They are inhibited by a high sodium intake, by denervation and by propranolol. A high sodium intake can overcome the effect of the lack of angiotensin II. A low sodium balance and the lack of angiotensin II did not have additive effects. The sodium effects did not appear to depend on the presence of the macula densa, the presence of angiotensin II, or the presence of the nerve supply. It was not evaluated whether baroreceptors may be important in allowing sodium effects to be processed, but in the experiments conducted there were no significant changes in blood pressure associated with alterations in sodium balance. Sodium balance has an important effect on synthesis and secretion. This effect does not appear to be mediated by the usual set of controls and raises questions as to the signal relating sodium balance to renin synthesis. Secretion does appear to depend on macula densa. The role of the macula densa appears to control the basal level of renin secretion and to permit the conversion and processing of prorenin to renin.

Clinical pharmacokinetics and pharmacodynamics of carvedilol

Carvedilol is an arylethanolamine that is a racemic mixture of 2 enantiomers. The S-(-)-enantiomer has beta-adrenoceptor blocking activity, while the racemate also has alpha 1-receptor blocking activity due to the activity of the R-(+)-enantiomer. The drug is rapidly absorbed and undergoes extensive first-pass metabolism in the liver. It reaches a peak concentration 1 to 2 hours postdose and has an elimination half-life of about 4 to 7 hours. Absorption is delayed by food. The drug is highly lipophilic and is highly protein bound. The drug is metabolised by the liver, with some metabolites having biological activity. The pharmacokinetic profile is not altered in the elderly or in patients with renal disease. However, bioavailability of the oral medication is greatly increased in patients with liver disease. Carvedilol lowers blood pressure as a result of its beta-blocking and vasodilatory activity. The reduction in blood pressure is similar to that achieved with other antihypertensive drugs, and there are no adverse effects on renal or cerebral blood flow. Carvedilol has been used in small numbers of patients with cardiac failure. It reduces left ventricular hypertrophy and has no significant adverse metabolic effects.

Role of the macula densa in renin synthesis and secretion

The secretion and synthesis of renin were studied in mice by measuring aortic, right and left renal vein renin, renal renin, and mRNA for renin. The role of the macula densa was evaluated in a kidney made hydronephrotic by tying the ureter 6 weeks earlier. There was no net secretion of renin from the left hydronephrotic kidney even when the mice were placed in a high secretory state by sodium restriction or enalapril. Sodium restriction and enalapril increased renin content to a similar extent in the normal and hydronephrotic kidney. High sodium intake decreased renin content in the normal and hydronephrotic kidney and also decreased the enalapril-stimulated renin content. Changes in mRNA in the same direction to renal renin implied that this was due to increased synthesis. Thus secretion and synthesis of renin can be disassociated. The macula densa is important for renin secretion but not for the stimulation of synthesis.

Effectiveness of blood pressure control with once daily administration of enalapril and perindopril

Ten patients who had their blood pressure controlled with enalapril (10 mg, n = 4; 20 mg, n = 6) and 10 control subjects on perindopril (4 mg, n = 6; 8 mg, n = 4) entered a double-blind crossover study. They received placebo or the active drug 1 week apart and had their blood pressure measured at 0, 2, 3, 4, and 24 h. Then they crossed over to the other angiotensin-converting enzyme inhibitors (4 mg perindopril congruent to 10 mg enalapril) and the double-blind study was repeated. Blood pressure control 2 to 4 h after drug administration was similar with both drugs (perindopril = 150 +/- 2/80 +/- 1; enalapril = 150 +/- 2/81 +/- 1). Twenty-four h after administration of perindopril blood pressure was lower than on enalapril (perindopril = 154 +/- 3/85 +/- 2; enalapril = 159 +/- 3/89 +/- 2). Enalapril, 2 to 4 h after administration, caused a greater decrease than placebo, whereas the change with perindopril did not differ from placebo. Twenty-four hours after receiving the active drug the blood pressure of subjects on perindopril did not differ from the peak effect when corrected for placebo and circadian variation, whereas the blood pressure on enalapril was higher. This study indicates that perindopril in the doses used has a longer duration of action than enalapril and is more suited to once daily use.

Role of uterine factors in the development of hypertension in SHR

1. To examine whether the uterine environment plays a role in the development of hypertension in the spontaneously hypertensive rats (SHR), we have compared fetal weight, placental weight, and amniotic fluid composition of SHR and Wistar-Kyoto (WKY) rats after 20 days of gestation. 2. Pregnant SHR and WKY were anaesthetized at 20 days of gestation and the uterus and embryonic sacs removed. Fetal and placental weights were recorded and amniotic fluid collected for measurement of volume, osmolality and electrolyte composition. 3. No significant difference was found in litter size and placental weight between SHR and WKY. Total embryonic sac weight and fetal weight of SHR were significantly lower than WKY. Amniotic fluid volume, sodium concentration and osmolality of SHR were significantly higher than WKY, while amniotic fluid potassium concentration of SHR was significantly lower than WKY. 4. Thus, the SHR foetus was significantly underweight compared to the WKY and was bathed in amniotic fluid with a significantly higher osmolality and sodium concentration. As the mature foetus is known to drink amniotic fluid, it is hypothesized that the elevated Na/K ratio in SHR amniotic fluid may instigate or accelerate the hypertensive process.

Effects of enalapril and Dup753 on renin synthesis in mice with one hydronephrotic kidney

1. Renin synthesis and secretion were investigated in mice with one hydronephrotic kidney. 2. Enalapril and Dup753 stimulated renin synthesis to a similar extent in the hydronephrotic and normal kidney. 3. Hydronephrosis did not prevent an increase in renin mRNA caused by enalapril and Dup753. 4. The results therefore indicate that the macula densa does not appear to be crucial for renin synthesis in the kidney under the inhibition of angiotensin II. 5. Thus angiotensin II plays an important role controlling renin gene expression in both the normal and hydronephrotic kidneys.

Effect of chronic portal hypertension on glutamine transport across rat intestinal brush border and basolateral membranes

The present study examined the effect of chronic portal hypertension on the intestinal transport of glutamine across the brush border membrane (BBM) and the basolateral membrane (BLM) of the rat enterocyte. Chronic portal hypertension was induced by partial portal vein ligation, and the results were compared with results in sham-operated rats. Transport studies were performed by using established techniques of isolated membrane vesicles. In chronic portal hypertensive rats, transport of glutamine in BBM vesicles (BBMVs) exhibited significant inhibition in the maximal velocity (Vmax) of both the Na(+)-dependent and the Na(+)-independent transport processes, with no significant changes in the apparent Michaelis-Menten constant (Km) of the carrier systems. Similarly, chronic portal hypertension caused a significant decrease in the Vmax of the Na(+)-dependent and the Na(+)-independent uptake processes in intestinal BLM vesicles (BLMVs), with no change in the apparent Km of the uptake systems. These changes in glutamine transport in BBMVs and BLMVs brought about by chronic portal hypertension are not due to differences in the relative purity of the vesicular preparations between the portal hypertensive and sham-operated rats, because similar degrees of enrichment and depurification of marker enzyme activities were seen in final vesicular preparations in the two rat groups. These results demonstrate that in chronic portal hypertension, glutamine transport across both poles of the enterocyte is impaired. At both the BBM and BLM domains, the impairment appears to be mediated via a decrease in the number (and/or activity) of the glutamine carrier systems, with no changes in their affinity.(ABSTRACT TRUNCATED AT 250 WORDS)

Transforming growth factor beta 1 and fibronectin messenger RNA in rat brain: responses to injury and cell-type localization

Transforming growth factor-beta 1 rapidly increases in adult rat brain in response to experimental lesions. This study characterized the schedule of changes, regional distribution, and cellular localization of striatal transforming growth factor-beta 1 messenger RNA and fibronectin messenger RNA following partial striatal deafferentation by frontal cortex ablation. Frontal cortex ablation induced striatal transforming growth factor-beta 1 messenger RNA elevations that coincided temporally and overlapped anatomically with the course of degeneration of cortico-striatal afferent fibers. Within three days post-lesioning, transforming growth factor-beta 1 messenger RNA was localized at the cortical wound. By 10 days, the anatomical site of transforming growth factor-beta 1 messenger RNA expression shifted to the dorsal half of the deafferented striatum and co-localized with OX-42+ immunostained microglia-macrophage at the site of degenerating afferent terminals. Similarly, fibronectin messenger RNA also shifted from the cortical wound to the deafferented striatum by 10 days post-lesioning. Fibronectin messenger RNA was localized to glial fibrillary acidic protein+ immunostained astrocytes surrounding degenerating corticostriatal afferents. Infusion of transforming growth factor-beta 1 peptide elevated striatal and cortical fibronectin messenger RNA. These findings suggest that microglia-macrophage associated with degenerating afferent fibres can upregulate transforming growth factor-beta 1 messenger RNA and may influence fibronectin messenger RNA synthesis in reactive astrocytes. This study suggests that transforming growth factor-beta 1 has a role in controlling extracellular matrix synthesis following brain injury, which is analogous to that in peripheral wound healing.

Somatostatin as a modulator of distal nephron water permeability

1. Experiments in vivo and in vitro were performed in the rat to define the role of somatostatin in modulating the hydro-osmotic action of arginine vasopressin. 2. Somatostatin had a biphasic effect on basal collecting duct diffusional water permeability with 10(-9) mol/l somatostatin producing a 14% reduction in permeability, whereas concentrations of 10(-6) and 10(-5) mol/l significantly increased basal water permeability by 13% and 22%, respectively. Somatostatin (10(-9) mol/l) also inhibited the increase in water permeability produced by arginine vasopressin, although this inhibitory effect was reduced by a 10-fold increase in arginine vasopressin concentration (5 ng/ml). 3. In the anaesthetized water-diuretic rat, low dose somatostatin (60 micrograms/h) increased free water clearance by 23% (P < 0.01), whereas increasing the somatostatin concentration (600 micrograms/h) produced a transitory 40% fall in free water clearance (P < 0.01). As in the experiment in vitro, somatostatin inhibited the action of arginine vasopressin, although a very high concentration of arginine vasopressin (250 ng/h) partly overcame this effect. 4. Glomerular filtration rate and renal electrolyte excretion (sodium, potassium, calcium, magnesium) were not altered by somatostatin, although renal inorganic phosphate excretion was increased. The papillary solute gradient was unaltered by somatostatin. 5. These results suggest that circulating somatostatin may have a physiological role in modulating distal nephron water transport with a low concentration directly inhibiting and a high concentration facilitating water transport. There is also evidence of competitive binding between somatostatin and arginine vasopressin which antagonizes the hydro-osmotic action of arginine vasopressin.

The role of the renal nerves in renin synthesis

1. Renin synthesis and secretion were studied in Balb/c mice with a denervated left kidney. 2. Denervation inhibited renin secretion. 3. Denervation reduced the renal renin content. 4. Denervation reduced renal renin mRNA. 5. Renal denervation inhibits renin secretion by blocking the synthetic system prior to mRNA formation.

Clinical efficacy of perindopril in hypertension

1. Perindopril's effectiveness in mild to moderate hypertension was evaluated in three studies. 2. Perindopril was more effective than sodium restriction in reducing blood pressure, and the effects were additive. 3. Perindopril was as effective as atenolol in reducing blood pressure, and was well tolerated. 4. Perindopril lowered blood pressure to the same extent as enalapril at peak drug levels but had a greater effect at the trough level of the drugs. 5. Perindopril is an effective antihypertensive agent with an acceptable side-effect profile in people with hypertension.

The effect of presentation and mode of delivery on neonatal outcome in the second twin

OBJECTIVE

The purpose of this study was to determine if cesarean delivery of the nonvertex second twin improved neonatal outcome.

STUDY DESIGN

We examined the maternal and neonatal records from 457 sets of twins delivered from 1985 to 1990. We compared 1- and 5-minute Apgar scores, umbilical artery and vein blood pH values, duration of neonatal hospitalization, the incidence and length of ventilation, intraventricular hemorrhage, birth trauma, and mortality rate between vertex and nonvertex second twins delivered either vaginally or by cesarean section.

RESULTS

The presentation and mode of delivery of the second twin was not associated with a significant difference in any of the outcome variables except for the 1-minute Apgar score, which was lower in the nonvertex group delivered vaginally.

CONCLUSION

Our data do not support routine cesarean delivery for twins of any birth weight when the second twin is nonvertex.

Preoperative radiotherapy for muscle-invading bladder-carcinoma

One hundred five patients with clinical stage T2-T4 transitional cell bladder carcinoma who completed either low-dose (20-26 Gy) or high dose (40-50 Gy) preoperative radiotherapy (RT) followed by cystectomy were reviewed. Five-year actuarial survival was 42%, 52%, and 17% for stages T2, T3, and T4, respectively. Five-year local control rates for stages T2, T3, and T4 was 93%, 93% and 22%, respectively. Survival, local control, distant metastasis and complications were similar for both preoperative regimens. The high rates of local control support the use of preoperative RT in selected patients with bladder carcinoma.

Local recurrence after cystectomy alone for bladder carcinoma

Although the role of preoperative irradiation in the treatment of bladder carcinoma is questioned, patterns of failure after cystectomy alone are not well documented. Local failure patterns were analyzed retrospectively in 83 patients (67 men and 16 women) treated with cystectomy without adjuvant therapy at three institutions. The follow-up period ranged from 0 to 167 months. Disease was assessed preoperatively by clinical stage and postoperatively by pathologic stage. Thirteen patients had pelvic recurrences, a 5-year actuarial failure rate of 18%. Pathologic stage was the only significant predictor of local recurrence, which ranged from 6% in patients with pT2 tumors to 51% in patients with pT3b tumors. The median time to local recurrence was 9 months (range, 3 to 62 months). Clearer documentation of failure patterns will provide a basis for evaluating survival with combined treatment methods, including preoperative radiation therapy, surgery, and chemotherapy.

Synthesis and Base Hydrolysis of the Pentaammine(dimethyl sulfide)cobalt(III) Ion

The synthesis of the trifluoromethanesulfonate salt of the pentaarnmine (dimethy1 sulfide)-cobalt(III) ion, [NH3)5Co-S(CH3)2]3+, is described along with the kinetics of its hydrolysis in basic and acidic solutions. The synthesis proceeds in 44% yield from the reaction of [(NH3)5Co-OSO2CF3] (CF3SO3)2 with CH3SCH3 in tetramethylene sulfone at 80�C. The salt has been characterized by elemental analysis, visible-U.V. spectroscopy, and 1H n.m.r. In basic solution the complex decomposes by Co-S cleavage to yield [(NH3)5CO-OH]2+ and non-coordinated CH3SCH3. The kinetics of this reaction were studied in phosphate buffers ranging from pH 8.50 to 11.67 ( �= 1.0 M); a linear dependence of the reaction rate on [OH-] was observed. At 25�C, kOH = 8.8 � 0.2 dm3 mol-1 s-1. Activation parameters, determined over a temperature range from 15 to 44�C, were ΔH‡ = 152 � 3 kJ mol-1 and Δ S‡ = 286 � 9 J K-1 mol-1. In 0.01 M HClO4 ( � = 1.0 M, 25�C), the cobaltsulfur bond is cleaved at a rate of 1.6×10-6 s-l. Activation parameters, determined over a temperature range from 25 to 60�C, were ΔH‡ = 106 � 5 kJ mol-1 and ΔS‡= -2 � 16 J K-1 mol-1.

Carotid stenosis in lacunar stroke

The prevalence of extracranial carotid stenosis in patients with a clinical syndrome of lacunar stroke has not been extensively studied using noninvasive methods. We performed carotid duplex sonography on 168 patients referred to the neurosonology laboratory with a diagnosis of ischemic stroke. Strokes were independently classified as lacunar or nonlacunar hemispheric infarction without knowledge of the ultrasound results. We excluded patients with infarcts that were clearly vertebrobasilar, presumed to be cardioembolic, or had occurred greater than 1 year earlier, and patients for whom classification of the nature and location of the event was not possible. Fifty-five patients had lacunar and 54 had nonlacunar stroke. No differences in age, sex, distribution, or prevalence of hypertension, diabetes, prior ischemia, or Hispanic surname existed between the two groups. Tobacco use was more frequent in the nonlacunar group (p less than 0.01). The prevalence of important extracranial carotid stenosis (greater than or equal to 50% diameter reduction) in the lacunar stroke group was 13% (seven of 55) in the ipsilateral and 4% (two of 55) in the contralateral carotid artery. Of the 54 patients with nonlacunar hemispheric stroke, 41% (22) had ipsilateral (p less than 0.01) and 26% (14) had contralateral (p less than 0.01) carotid stenosis. This study suggests that important carotid stenosis is infrequent among patients presenting with a clinical syndrome of lacunar stroke. These data impact on decisions regarding cerebrovascular work-up in such patients.

The role of the macula densa in renin synthesis

1. The role of the macula densa in renin synthesis was studied using mice with one hydronephrotic kidney. 2. Renin synthesis was assessed by measurement of renal renin, renal mRNA for renin and plasma renin. 3. Sodium depletion stimulated mRNA and renal renin to a similar extent in the hydronephrotic and contralateral kidney. 4. Enalapril stimulated mRNA concentration in both kidneys but renal renin did not rise in the hydronephrotic kidney. 5. Propranolol did not alter the response to sodium depletion in either kidney. 6. The macula densa is not crucial for the stimulation of renin synthesis following sodium depletion. However, it may regulate renin production after mRNA synthesis, possibly by controlling the conversion of prorenin to renin.