Sample size nomograms for interpreting negative clinical studies

Assessing the Evidence in Evidence-Based Medicine

Evidence-based medicine (EBM) has become a fixture in today's medical practice. Evidence consists of memorialized observations and should be contrasted with dogmatic pronouncements and/or hypotheses. Evidence has varying degrees of reliability. The randomized clinical trial (RCT) or a systematic review of RCTs is accorded the highest level of credibility and expert opinion the lowest. This ranking reflects the internal validity (degree to which factors in the study interfere with the gathering or interpretation of the observations) of the study design; more valid designs are more credible. The provision of healthcare requires an almost constant assessment of evidence. In so doing, there are a number of principles of EBM that need to be kept in mind: Association can never prove causation. Various methodologic biases can influence conclusions made in both RCTs and observational studies. The strength of RCTs is in the elimination of confounding bias. Surrogate outcomes must be validated in RCTs assessing how they are changed compared with the clinical outcomes. Subgroup analyses cannot prove hypotheses although they can generate them. P < 0.05 is not the same as truth. Type I errors are more likely to occur when multiple analyses are performed, when trials are prematurely stopped for perceived benefit when there was no a priori plan to do so, or in small papers with dramatic results that are selectively published. The failure to find a difference does not mean that no difference exists (type II error).

Hostage to History: The Duration of Antimicrobial Treatment for Acute Streptococcal Pharyngitis

Oral antimicrobial treatment of acute streptococcal pharyngitis commonly is given for 10 days. An investigation was conducted of journal publications and textbooks from the dawn of the antimicrobial era to the present in order to discover the basis for this settled practice. Current treatment duration for acute streptococcal pharyngitis was established half a century ago under conditions significantly different from those currently encountered by the average clinician. The 10-day treatment standard evolved without scientific justification. There have been no therapeutic trials that have validated the necessity for 10 days of oral antimicrobial treatment. Yet, despite the lack of a scientific foundation, the rarity of acute rheumatic fever in developed countries, the high failure rate for streptococcal eradication and evidence that short-course therapy with a nonpenicillin antimicrobial yields equivalent eradication rates, the 10-day rule persists because of long clinical usage and the inherent power of the number 10. Efforts to change this clinical benchmark will likely meet with resistance from practicing physicians.

Comparison of Pharmaceutical Calculations Learning Outcomes Achieved Within a Traditional Lecture or Flipped Classroom Andragogy

Objective. To compare learning outcomes achieved from a pharmaceutical calculations course taught in a traditional lecture (lecture model) and a flipped classroom (flipped model). Methods. Students were randomly assigned to the lecture model and the flipped model. Course instructors, content, assessments, and instructional time for both models were equivalent. Overall group performance and pass rates on a standardized assessment (Pcalc OSCE) were compared at six weeks and at six months post-course completion. Results. Student mean exam scores in the flipped model were higher than those in the lecture model at six weeks and six months later. Significantly more students passed the OSCE the first time in the flipped model at six weeks; however, this effect was not maintained at six months. Conclusion. Within a 6 week course of study, use of a flipped classroom improves student pharmacy calculation skill achievement relative to a traditional lecture andragogy. Further study is needed to determine if the effect is maintained over time.

A comparison of 3 antibiotic regimens for prevention of postcesarean endometritis: an historical cohort study

BACKGROUND

Prophylactic antibiotics are of proven value in decreasing the frequency of postcesarean endometritis. The beneficial effect of prophylaxis is enhanced when the antibiotics are administered before the surgical incision as opposed to after the clamping of the umbilical cord. However, the optimal antibiotic regimen for prophylaxis has not been established firmly.

OBJECTIVE

The purpose of this study was to compare 3 different antibiotic regimens for the prevention of postcesarean endometritis.

STUDY DESIGN

This retrospective historical cohort study was conducted at the University of Florida, which is a tertiary care facility that serves a predominantly indigent patient population. In the period January 2003 to December 2007, our standard prophylactic antibiotic regimen for all women who had cesarean delivery was cefazolin (1 g) administered immediately after the baby's umbilical cord was clamped. In November 2008, we began to administer the combined regimen of cefazolin (1 g intravenously) plus azithromycin (500 mg intravenously); both were given 30-60 minutes before the skin incision. In the period of January-December 2014, we continued the dual agent regimen but based the dose of cefazolin on the patient's body mass index: 2 g intravenously if the body mass index was <30 kg/m(2) and 3 g if the body mass index was >30 kg/m(2). The surgical technique was consistent throughout all 3 time periods. Our primary endpoint was the frequency of endometritis in each time period. This diagnosis was based on fever ≥37.5°C, lower abdominal pain and tenderness, the exclusion of other localizing signs of infection, and the requirement for administration of therapeutic antibiotics. In the first year after beginning the new antibiotic regimen, we also monitored the frequency of neonatal sepsis evaluations and compared it with the frequency that was recorded during the year immediately preceding the change in antibiotic regimens.

RESULTS

During the entire period 2003-2014, 29,633 women delivered at our institution; 6455 women (22%) had a cesarean delivery. In the period January 2003 to December 2007, 1034 women had a primary or repeat cesarean delivery. One hundred seventy women (16.4%; 95% confidence interval, 14.4-18.4%) developed endometritis. In the period November 2008 to December 2013, 4484 women had a primary or repeat cesarean delivery. Fifty-nine patients (1.3%; 95% confidence interval, 1.0-1.7%) developed endometritis (P < .0001 compared with period 1). In the year 2014, 937 women had a cesarean delivery; 22 of them (2.3%, 95% confidence interval, 1.3-3.3%) developed endometritis (P < .0001 compared with period 1 and P > .5 and <.10 compared with period 2). The frequency of evaluations for suspected neonatal sepsis in infants who were delivered to mothers who had cesarean delivery was 17.6% in the period January to December 2007 and 19.3% in the period November 2008 to November 2009 (relative risk, 1.1; 95% confidence interval, 0.7-1.9). One infant had proven sepsis in the former period; 2 infants had proven sepsis in the latter period (not significant).

CONCLUSIONS

When administered before skin incision, the combination of cefazolin plus azithromycin was significantly more effective in the prevention of endometritis than the administration of cefazolin after cord clamping; the rate of endometritis was reduced to a very low level without increasing the rate of neonatal sepsis evaluations.

Treatment of Childhood Complicated Community-Acquired Pneumonia with Amoxicillin/Sulbactam

The clinical and microbiological efficacy, as well as the tolerability of the amoxicillin/sulbactam combination as empiric treatment for complicated community-acquired pneumonia (CCAP) were evaluated in children from 3 months to 15 years with CCAP who were randomized 1:1 to receive either amoxicillin/sulbactam or cefuroxime. Of 234 patients hospitalized with CCAP in the study period (June, 1999-April, 2002), 62 patients qualified for the study: 32 received amoxicillin/sulbactam and 30 cefuroxime. Two were excluded. Demographic and clinical data showed that both groups were comparable at entry. One etiologic agent was identified in 55% of the patients, with Streptococcus pneumoniae being the most frequent. After treatment, the days of fever, duration of intravenous treatment, and hospitalization stay were similar in both groups. Overall favorable clinical responses were comparable: 97% for amoxicillin/sulbactam vs 100% for the comparative therapy. There was good tolerance to both drugs. Amoxicillin/sulbactam produced a satisfactory therapeutic outcome similar to that of cefuroxime for treatment of CCAP, and may be an appropriate choice for the treatment of this serious pediatric infection.

Effects of nimesulide on pain and on synovial fluid concentrations of substance P, interleukin-6 and interleukin-8 in patients with knee osteoarthritis: comparison with celecoxib

OBJECTIVE

This study was designed to investigate the analgesic effects of nimesulide and celecoxib in patients with knee osteoarthritis (OA). In patients with joint effusion, the effects of these non-steroidal anti-inflammatory drugs (NSAIDs) on synovial fluid concentrations of substance P (SP), interleukin (IL)-6 and IL-8 also were evaluated.

METHODS

Patients were randomly assigned either nimesulide (100 mg twice a day) or celecoxib (200 mg once a day) for 2 weeks. The intensity of joint pain was assessed with a 100-mm visual analogue scale (VAS). Furthermore, patients completed questions about analgesic efficacy and overall tolerability of the treatments on a five-point categorical scale. Synovial fluid samples were drawn at baseline, 30 min after the first drug intake (day 1), and 30 min after the last drug intake (day 14).

RESULTS

We enrolled 44 patients, 20 of whom had a joint effusion. In this group, the effects of nimesulide were more marked than for celecoxib, with evidence of a faster onset of the analgesic action. Both after a single or repeated administration, nimesulide significantly reduced the synovial fluid concentrations of SP and IL-6. Celecoxib, on the other hand, did not change the concentrations of SP and significantly reduced the levels of IL-6 only on day 14. None of the drugs affected IL-8. Both drugs were generally well tolerated.

CONCLUSIONS

These results provide evidence that nimesulide is an effective agent for the symptomatic treatment of OA. The effect on inflammatory pain mediators is consistent with the fast analgesic action of this NSAID.

Lipid-based Nose Ointment for Allergic Rhinitis

OBJECTIVE

To assess the efficacy of a lipid-based nose ointment in treating allergic rhinitis.

STUDY DESIGN AND SETTING

Prospective, open, randomized, controlled clinical study in the outpatient departments of 2 tertiary care centers.

RESULTS

No specific adverse effects were observed. The nose ointment under investigation led to a significant improvement in sneezing and nasal itching (17 patients). There was no significant change for nasal congestion and rhinorrhea in the intention-to-treat sets. However, there was still a significant drop of the mean relative total symptom score derived from the individual scores. All scores remained unchanged in the untreated control group (16 patients).

CONCLUSION

Topical application of the nose ointment as a supportive treatment leads to a significant improvement of symptoms in allergic rhinitis.

SIGNIFICANCE

The prevalence of allergic rhinitis is about 10% to 20% in the population. Our study results are encouraging and should be assessed in further research because changes in the therapeutic guidelines may be suggested.

EBM RATING

A.

Die Anwendung lipidhaltiger Nasensalbe bei allergischer Rhinitis — eine Therapieoption?

BACKGROUND

Some 10-20% of the population suffer from allergic rhinitis. A recently discussed and interesting, albeit disputed therapy option is the use of a lipid-based nasal ointment.

METHOD

To test the efficacy of this nasal ointment as an adjuvant therapy for allergic rhinitis, a two-centre, prospective, open, randomized, controlled clinical study was carried out.

RESULT

In the study, 17 patients using the test agent were compared with 16 who did not. For the group using the test agent, before and after comparisons showed a significant (about 40%) improvement in the medium, relative total range of symptoms (Wilcoxon-Mann-Whitney U-test, P<0.01) based on the individual parameters of sneezing attacks, nasal itching, nasal secretion and nasal obstruction. In the control group, non-use of the test agent meant that the total range of symptoms remained unchanged. No side effects were recorded.

CONCLUSION

The test agent used in our study contains a lipid fraction, in this case in the form of high purity, long chain hydrocarbons. By local application, a significant improvement of the total symptomatology was shown. The mechanism has not been clarified. Owing to the efficacy and low risk of side effects, this seems to be a promising adjuvant therapy for allergic rhinitis. The probetoric use of this nasal ointment as a supportive therapeutic option should be reviewed in further clinical studies.

Epidemiologic studies of adverse effects of anti-retroviral drugs: how well is statistical power reported

PURPOSE

To determine whether there is a difference in average statistical power between pharmacoepidemiologic studies of anti-retroviral adverse drug effects (ADEs) sponsored by for-profit versus non-profit organizations.

METHODS

We studied all published pharmacoepidemiologic studies of ADEs associated with the 15 anti-retroviral drugs approved through the end of 1999. A priori, the primary outcome was the power of each study to detect a clinically important difference in the risk for an adverse effect among patients exposed to the study drug(s). We could not evaluate this outcome because of the infrequent reporting of power calculations. We instead report the distribution of studies across a 5-tiered measure of adequacy of reporting of statistical power, as well as the sponsorship of these studies.

RESULTS

Of 48 studies meeting our inclusion criteria, only 1 (2%) reported either a completed, a priori power calculation or sufficient details for readers to calculate the power to detect a pre-defined, clinically important effect. Thirty-five studies (73%) reported the minimum information required for sophisticated readers to determine the power to detect an event rate of interest to them; 6 additional studies (13%) reported confidence intervals around at least one summary effect measure and 6 (13%) provided no indication of power or uncertainty. Of the 41 studies for which sponsorship was determined, only 3 (7%) were sponsored by for-profit organizations.

CONCLUSIONS

The poor reporting of statistical power in this sample suggests a need for guidelines to improve the reporting of pharmacoepidemiologic studies of ADEs. Future research is needed to determine whether the observed paucity of industry-sponsored observational studies of anti-retroviral ADEs extends to other clinical areas, and if so, to identify the causes of this phenomenon.

Evaluation of Periapical Lesion Healing by Correction of Gray Values

The purpose of this study was to compare two methods for evaluating periapical healing in humans: the periapical index (PAI) and a gray value correction method. Fifty human teeth with a periapical lesion were endodontically treated. Radiographs, with a special aluminum device, were taken postoperatively, after 3 months and after 6 months. The PAI was recorded at each period of time, and a Kruskall and Wallis test was performed to compare the three groups. After scanning, the size of the lesion and its gray value were recorded. The aluminum device allowed the gray values to be equalized. An analysis of variance followed by a Duncan test was performed to compare the three groups. The teeth that showed no sign of healing according to the PAI were separately analyzed by an analysis of variance and a Duncan test. The PAI (n = 50) showed signs of periapical healing over time (p < 0.01). The analysis of variance, based on gray value evaluation (n = 50), also showed signs of periapical healing over time (p < 0.002). The analysis of variance of teeth with the same PAI over time (n = 15 at 3 months, and n = 5 at 6 months), based on gray value evaluation showed statistically significant differences among the 3 groups (p < 0.02). These results show that the gray level correction method is powerful and may reduce the risks of false negative responses during assessment of treatment results or epidemiological studies.

Differential effects of sodium selenite in reducing tissue damage caused by three hemoglobin-based oxygen carriers

Three “blood substitutes,” a diaspirin cross-linked human hemoglobin (DBBF-Hb), a bovine polymerized hemoglobin (PolyHbBv), and a human polymerized hemoglobin ( O-R-PolyHbA0), that have undergone clinical trials are used in this study. Previously, we showed in the rat that coadministration of sodium selenite (Na2SeO3) and DBBF-Hb significantly decreased mesenteric venular leakage and epithelial disruption produced by DBBF-Hb alone but did not reduce mast cell degranulation unless given orally. The purpose of this study was to determine whether Na2SeO3 produced similar beneficial responses when used with PolyHbBv and O-R-PolyHbA0. In anesthetized Sprague-Dawley rats, the mesenteric microvasculature was perfused with PolyHbBv or O-R-PolyHbA0, with and without Na2SeO3 in the perfusate and suffusate, for 10 min, followed by FITC-albumin for 3 min, and then fixed for microscopy. Na2SeO3 did not reduce leak number or area in preparations perfused with PolyHbBv and only reduced leak number (but not significantly) in preparations perfused with O-R-PolyHbA0. Na2SeO3 significantly increased mesenteric mast cell degranulation and impaired epithelial integrity in animals treated with PolyHbBv. In vitro, Na2SeO3 significantly reduced the oxidation rate of DBBF-Hb in the presence of oxidants, had little effect on PolyHbBv, and increased the oxidation rate of O-R-PolyHbA0. These results suggest that Na2SeO3 moderates hemoglobin-induced damage, at least partly, through its redox interactions with the heme sites in the hemoglobin molecules studied and that accessibility of the heme site to Na2SeO3 governs those interactions.

Effects of tramadol on synovial fluid concentrations of substance P and interleukin-6 in patients with knee osteoarthritis: comparison with paracetamol

Both the analgesic drugs tramadol and paracetamol are widely used for the symptomatic therapy of osteoarthritis (OA). The aim of this double-blind, randomised study in patients with knee OA was to compare their effects on synovial fluid concentrations of interleukin (IL)-6 and substance P (SP). Moreover, we evaluated plasma and synovial fluid concentrations of tramadol and its active metabolite (O-desmethyl-tramadol, M1) after oral treatment with this drug. Twenty patients were enrolled. A group of 10 patients received tramadol (50 mg three times a day), and another group of 10 patients were treated with paracetamol (500 mg three times a day) for 7 days. Both drugs significantly reduced the intensity of joint pain. The synovial fluid concentrations of SP were significantly reduced only by the treatment with tramadol. In this group of patients, IL-6 synovial fluid concentrations were slightly, but not significantly, decreased. Paracetamol did not significantly change the synovial fluid concentrations of SP and IL-6. After oral administration, a considerable amount of tramadol was measurable in synovial fluid. Both in plasma and synovial fluid the concentrations of M1 were markedly lower than those of tramadol, with a T/M1 ratio of 14.7+/-4.6 and 9.3+/-3.9, respectively. These data demonstrate that the activity of tramadol may involve the modulation of inflammatory mediators. Moreover, they indicate that after oral treatment with tramadol, both the parent drug and its active metabolite can penetrate into synovial fluid.

A Randomised, Double-Blind, Clinical Trial Comparing the Efficacy of Nimesulide, Celecoxib and Rofecoxib in Osteoarthritis of the Knee

Joint pain is the main complaint in patients affected by osteoarthritis (OA), and NSAIDs are commonly used to treat pain associated with OA. Over the past few years, cyclo-oxygenase (COX)-2-selective inhibitors have been proved to have certain advantages over non-selective NSAIDs and have been increasingly used for pain management in patients with OA.

OBJECTIVE

The main objective of this randomised, double-blind, within-patient study was to compare the analgesic efficacy of three COX-2 inhibitors in 30 patients affected by symptomatic OA of the knee. We evaluated the effects of oral nimesulide (100mg), celecoxib (200mg) and rofecoxib (25mg). Each drug was administered for 7 days.

METHODS

Analgesic efficacy was determined using the patient's assessment of pain on a visual analogue scale (VAS) and by total pain relief over 3 hours (TOPAR3) on the first and last days of treatment. In addition, the overall analgesic efficacy and tolerability were determined by a global assessment by the patient at the end of each week of treatment, using 5-point categorical scales. At the end of the study, each patient was asked about which of the three forms of treatment they would choose as a continuation of the pain therapy.

RESULTS

Taking all the results into consideration, nimesulide proved to be significantly more effective in providing symptomatic relief than did celecoxib and rofecoxib. Furthermore, nimesulide provided more rapid relief of pain associated with walking than did the other two drugs tested. Patients expressed similar preference for nimesulide and rofecoxib, but a lesser preference for celecoxib treatment. No patient withdrew from the study because of adverse events and the three different forms of treatment were generally safe and well tolerated.

CONCLUSION

The present data confirm our previous observations in patients with rheumatoid arthritis, further suggesting that nimesulide represents an effective agent for the treatment of joint pain, with particular reference to the rapid onset of its analgesic effect.

Sodium selenite reduces hemoglobin-induced venular leakage in the rat mesentery

Modified Hbs are being developed as "blood substitutes," but intravascular injection of diaspirin cross-linked Hb (DBBF-Hb) can produce venular leakage. Hb toxicity may arise from reactive oxygen species, so the antioxidant sodium selenite (Na(2)SeO(3)) was used in an attempt to reduce leak formation. In anesthetized Sprague-Dawley rats, one-half of which received 2 x 10(-6) g/ml Na(2)SeO(3) in their drinking water for 3 wk, the mesenteric microvasculature was perfused with 2 mg/ml DBBF-Hb (N = 8) for 10 min. Controls (N = 7) received saline. This was followed by perfusion with FITC-albumin for 3 min, fixation, and microscopic examination. In rats given DBBF-Hb, Na(2)SeO(3) significantly reduced leak number, leak area, and mast cell degranulation. Venular leakage was also reduced in rats that only received Na(2)SeO(3) locally during DBBF-Hb perfusion. However, Na(2)SeO(3) did not affect animals receiving cyanomet-DBBF-Hb instead of DBBF-Hb and significantly increased leak number and mast cell degranulation in animals receiving saline. In vitro, Na(2)SeO(3) reduced the oxidation rate of DBBF-Hb while in the presence of oxidants. These results suggest that Na(2)SeO(3) reduces DBBF-Hb-induced microvascular leakage partly by retarding the oxidation of its heme iron.

Comparison of effects of two hemoglobin-based O(2) carriers on intestinal integrity and microvascular leakage

Two "blood substitutes," a diaspirin cross-linked human hemoglobin [bis(3,5 dibromosalicyl)fumarate, DBBF-Hb] and a bovine polymerized hemoglobin (PolyHbBv), advanced to clinical trials, are used in this study. Previously, we have shown that injection of DBBF-Hb into the rat circulation produces venular leakage and intestinal epithelial disruption. The purpose of this study was to determine whether PolyHbBv, currently approved for veterinary use in the United States, shows similar effects. In anesthetized Sprague-Dawley rats, the mesenteric microvasculature was perfused with DBBF-Hb (n = 6), PolyHbBv (n = 5), cyanomet Hb (CNmet-DBBF-Hb), or HEPES-buffered saline with 0.5% bovine serum albumin (HBS-BSA) (controls, n = 7) for 10 min, followed by FITC-albumin for 3 min, and then fixed for microscopy. For DBBF-Hb, the mean leak number per micrometer venule length [2.41 +/- 0.33 (+/-SE) x 10(-3)] was significantly greater than for PolyHbBv (0.53 +/- 0.14 x 10(-3)), CNmet-DBBF-Hb (0.36 +/- 0.14 x 10(-3)), and HBS-BSA (0.12 +/- 0.08 x 10(-3)) (P < 0.01). Corresponding quantities for leak area were 0.10 +/- 0.03, 0.010 +/- 0.003, 0.005 +/- 0.003, and 0.02 +/- 0.02 microm(2)/microm. In rats injected with DBBF-Hb (n = 8), intestinal epithelial integrity was significantly compromised compared with those injected with PolyHbBv (n = 5) or saline (n = 6). These results indicate that intravascular PolyHbBv produces significantly less disruption of the intestinal exchange barrier than does DBBF-Hb, probably because the heme is not so easily oxidized.

Low-molecular-weight heparin for the treatment of patients with mechanical heart valves

BACKGROUND

The interruption of oral anticoagulant (OAC) administration is sometimes indicated in patients with mechanical heart valves, mainly before noncardiac surgery, non-surgical interventions, and pregnancy. Unfractionated heparin (UH) is currently the substitute for selected patients. Low-molecular-weight heparin (LMWH) offers theoretical advantages over UH, but is not currently considered in clinical guidelines as an alternative to UH in patients with prosthetic valves.

HYPOTHESIS

The aim of the present study was to review the data accumulated so far on the use of LMWH in this patient population and to discuss its applicability in common practice.

METHODS

For this paper, the current medical literature on LMWH in patients with mechanical heart valves was extensively reviewed.

RESULTS

There were eight series and six case reports. None of the studies was randomized, and only one was prospective. Data to establish the thromboembolic risk were incomplete. After excluding case reports, the following groups were constructed: (a) short-term administration, after valve insertion (n = 212); (b) short-term, perioperative (noncardiac)/periprocedural (n = 114); (c) long-term, due to intolerance to OAC (n = 16); (d) long-term, in pregnancy (n = 10). The incidence rate of thromboembolism was 0.9% for all the studies and 0.5, 0, 20, and 0% in groups a, b, c, and d, respectively; for hemorrhage, the overall rate was 3.4% (3.8, 2.6, 10, and 0% for the respective groups).

CONCLUSIONS

In patients with mechanical heart valves, short-term LMWH therapy compares favorably with UH. Data on mid- and long-term LMWH administration in these patients are sparse. Further randomized studies are needed to confirm the safety and precise indications for the use of LMWH in patients with mechanical heart valves.

Determination of the clinical importance of study results

Formal statistical methods for analyzing clinical trial data are widely accepted by the medical community. Unfortunately, the interpretation and reporting of trial results from the perspective of clinical importance has not received similar emphasis. This imbalance promotes the historical tendency to consider clinical trial results that are statistically significant as also clinically important, and conversely, those with statistically insignificant results as being clinically unimportant. In this paper, we review the present state of knowledge in the determination of the clinical importance of study results. This work also provides a simple, systematic method for determining the clinical importance of study results. It uses the relationship between the point estimate of the treatment effect (with its associated confidence interval) and the estimate of the smallest treatment effect that would lead to a change in a patient's management. The possible benefits of this approach include enabling clinicians to more easily interpret the results of clinical trials from a clinical perspective, and promoting a more rational approach to the design of prospective clinical trials.

Effect of angiotensin II on pulse wave velocity in humans is mediated through angiotensin II type 1 (AT(1)) receptors

The objective of this study was to examine the effect of angiotensin II (Ang II) and angiotensin II type 1 (AT(1)) receptor blockade on pulse wave velocity (PWV) in healthy humans. We studied nine young male volunteers in a double-blind randomised crossover design. Carotid-femoral PWV (an index of arterial stiffness) was measured by using a Complior machine. Subjects were previously treated for 3 days with once-daily dose of either a placebo or valsartan 80 mg. On the third day, they were infused with either placebo or 5 ng/kg/min of Ang II over 30 min. Subjects thus received placebo capsule + placebo infusion (P), valsartan + placebo infusion (V), placebo + Ang II infusion (A), and valsartan + Ang II infusion (VA) combinations. Heart rate (HR), blood pressure and PWV were recorded at baseline and then every 10 min during infusion and once after the end of infusion. There were significant increases in systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) with A compared with P (P = 0.002, P = 0.002, P = 0.001 respectively). These rises in blood pressure were completely blocked by valsartan. A significant rise in PWV by A was seen compared with P (8.38 +/- 0.24 vs 7.48 +/- 0.24 m/sec, P = 0.013) and was completely blocked by valsartan; VA compared with P (7.27 +/- 0.24 vs 7.48 +/- 0.24 m/sec, P = NS). Multiple linear regression analysis showed that blockade of Ang II induced increase in blood pressure by valsartan contributed to only 30% of the total reduction in Ang II induced rise in PWV (R(2) = 0.306). The conclusions were that valsartan completely blocks the effect of Ang II on PWV. The effect of Ang II on PWV is mediated through AT(1)receptors. Reduction in PWV by Ang II antagonist is not fully explained by its pressure lowering effect of Ang II and may be partially independent of its effect on blood pressure.

Buccal versus intravaginal misoprostol administration for cervical ripening

OBJECTIVE

The purpose of this study was to compare the efficacy of misoprostol that is administered in the buccal pouch with the intravaginal route of administration.

STUDY DESIGN

One hundred fifty-seven pregnant women with a singleton live gestation, Bishop score of <7, estimated fetal weight of <4500 g, and gestational age of >24 weeks were randomized to receive misoprostol that would be placed either in the buccal pouch or vagina every 6 hours. In the buccal group, after the first 2 doses of 200 microg, the dose was increased to 300 microg for the duration of the study (up to a total of 1600 microg). In the vaginal group, after the first 2 doses of 50 microg, the dose was increased to 100 microg for the duration of the study (up to a total of 500 microg). The primary outcome variable was the interval from the first dose to vaginal delivery. Power calculations indicated the need to enroll 71 patients in each arm of the study, which would allow for the detection of a 4-hour reduction in vaginal birth interval for buccal misoprostol.

RESULTS

The hours from drug administration to vaginal delivery were similar between the buccal and vaginal groups (23.5 +/- 20.8 hours versus 21.3 +/- 13.4 hours), respectively. Thirty-five women (63%) versus 34 women (67%) delivered vaginally within 24 hours (P = not significant). The incidence of tachysystole was higher in the buccal group, 28 occurrences (38%) versus 15 occurrences (19%; P =.01).

CONCLUSION

Buccal misoprostol is effective for cervical ripening but results in a higher incidence of tachysystole than does intravaginal administration.

Selenium reduces hemoglobin-induced epithelial damage to intestinal mucosa

Modified hemoglobins are being considered as possible "blood substitutes." Experiments were performed to determine whether diaspirin cross-linked hemoglobin (DBBF-Hb) produces epithelial damage and whether this is reduced by selenium (Se). Anesthetized Sprague-Dawley rats, half of which received 2 x 10(-6) g/ml Se, daily for 3 weeks, in their drinking water, were injected with a 5 ml bolus of 10 mg/ml DBBF-Hb. Control animals received saline (5 animals per group). After 30 minutes, the intestine was perfusion-fixed for light and electron microscopy. Eighty villi per rat were assigned an epithelial integrity index (E.I.), ranging from 1 (intact) to 3 (some cell-cell and cell-basement membrane separation). In non-Se rats, E.I. was significantly compromised by DBBF-Hb, compared to HBS-BSA (2.47+/-0.57 (SD) vs. 1.36+/-0.49, p<0.001). In Se rats, neither injection with DBBF-Hb or HBS-BSA caused epithelial damage (1.03+/-0.17 vs. 1.07+/-0.26). Mast cell degranulation per villus (MCD) was measured in 60 villi per rat. In non-Se rats, MCD was significantly greater after DBBF-Hb than after HBS-BSA injection (1.83+/-1.42 vs. 0.2+/-0.4). Supplementary Se did not reduce this effect. In fact, MCD was significantly increased in both sets of rats compared to their non-Se counterparts (3.27+/-2.40 and 1.48+/-1.70 for DBBF-Hb and HBS-BSA, respectively). Since mast cell mediators damage cells, Se must protect the mucosal epithelium in some way.

Intramuscular testosterone esters and plasma lipids in hypogonadal men: a meta-analysis

PURPOSE

It is unclear whether intramuscular administration of testosterone esters to hypogonadal men is associated with changes in plasma lipids. We therefore analyzed 19 studies published between 1987 and 1999 that focused on male subjects with nonexperimental hypogonadism, treated subjects with an intramuscular testosterone ester and reported pretreatment and post-treatment concentrations of total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL) cholesterol, or total triglyceride.

METHODS

We calculated study-specific, post-treatment minus pretreatment differences in each plasma lipid concentration (mean [95% confidence interval]). After testing of between-study homogeneity, we combined the study-specific differences. We then determined whether heterogeneity of differences could be explained in models of the differences on study and patient characteristics (mean +/- SE) before and after excluding extreme values using a multiple outlier procedure.

RESULTS

The studies represented 272 hypogonadal men (age 44 +/- 4 years; 20% with hypergonadotropic hypogonadism; total testosterone 0.5 +/- 0.2 ng/mL) who received, on average, 179 +/- 13 mg intramuscular testosterone ester every 16 +/- 1 days for 6 +/- 1 months. Fixed-effects estimates of post-treatment minus pretreatment differences were -14 [-17 to -11] mg/dL (total cholesterol), -5 [-8 to -1] mg/dL (LDL cholesterol), -4 [-5 to -2] mg/dL (HDL cholesterol), and -1 [-6 to + 4] mg/dL (triglyceride). Decreases in HDL cholesterol were larger at lower dosages of testosterone ester (r = -0.54, P = 0.055), but were not explained by attrition, regression to the mean, dosing frequency or duration, concomitant elevation of plasma total testosterone, aromatization of testosterone to estradiol, or other study and patient characteristics.

CONCLUSION

Intramuscular administration of testosterone esters to hypogonadal men is associated with a small, dosage-dependent decrease in HDL cholesterol and concomitant declines in total cholesterol and LDL cholesterol. The aggregate effect of these changes on cardiovascular risk remains unknown but deserves further study.

Effect of the angiotensin II type 2-receptor gene (+1675 G/A) on left ventricular structure in humans

OBJECTIVES

Our study goal was to analyze whether gene variants of angiotensin II type 2-receptor (AT2-R) modulate the effects of angiotensin II on the left ventricle (LV).

BACKGROUND

Experimental data suggest that angiotensin II modifies ventricular growth responses via angiotensin II type 1-receptors (AT1-R) and AT2-R.

METHODS

In 120 white, young male subjects with normal or mildly elevated blood pressure, we assessed plasma angiotensin II and aldosterone concentrations (RIA), 24-h urinary sodium excretion, 24-h ambulatory blood pressure and LV structure (two-dimensional guided M-mode echocardiography). The intronic +1675 G/A polymorphism of the X-chromosomal located AT2-R gene was investigated by single-strand conformational polymorphism analysis and DNA-sequencing.

RESULTS

Hypertensive subjects with the A-allele had a greater LV posterior (11.0 +/- 1.3 vs. 9.9 +/- 1.3 mm, p < 0.001), septal (11.8 +/- 1.4 vs. 10.1 +/- 1.2 mm, p < 0.001) and relative wall thickness (0.44 +/- 0.06 vs. 0.39 +/- 0.06, p < 0.01) as well as LV mass index (138 +/- 23 vs. 120 +/- 13 g/m2, p < 0.001) than those with the G-allele. Confounding factors (i.e., body mass index and surface area, plasma angiotensin II, sodium excretion, systolic and diastolic ambulatory blood pressure) were similar between the two genotypes. In normotensive subjects, relative wall thickness (0.36 +/- 0.05 vs. 0.35 +/- 0.05) and LV mass index (115 +/- 21 vs. 112 +/- 17 g/m2) were nearly identical across the two genotypes, with similar confounding variables.

CONCLUSIONS

Our data indicate that the X-chromosomal located +1675 G/A-polymorphism of the AT2-R gene is associated with LV structure in young male humans with early structural changes of the heart due to arterial hypertension.

Extracorporeal shock wave lithotripsy for clearance of bile duct stones resistant to endoscopic extraction

BACKGROUND

Endoscopic extraction of bile duct stones after sphincterotomy has a success rate of up to 95%. Failures occur in patients with extremely large stones, intrahepatic stones, and bile duct strictures. This study examined the efficacy and the safety of extracorporeal shock-wave lithotripsy in a large cohort of patients in whom routine endoscopic measures including mechanical lithotripsy had failed to extract bile duct stones.

METHODS

Out of 1587 consecutive patients, endoscopic stone extraction including mechanical lithotripsy was unsuccessful in 313 (20%). These 313 patients (64% women, median age, 73 years) underwent high-energy extracorporeal shock-wave lithotripsy. Stone targeting was performed fluoroscopically (99%) or by ultrasonography (1%).

RESULTS

Complete clearance of bile duct calculi was achieved in 281 (90%) patients. In 80% of the patients, the fragments were extracted endoscopically after shock-wave therapy; spontaneous passage was observed in 10%. For patients with complete clearance compared with those without there were no differences with regard to size or number of the stones, intrahepatic or extrahepatic stone location, presence or absence of bile duct strictures, or type of lithotripter. Cholangitis (n = 4) and acute cholecystitis (n = 1) were the rare adverse effects.

CONCLUSIONS

In patients with bile duct calculi that are difficult to extract endoscopically, high-energy extracorporeal shock-wave lithotripsy is a safe and effective therapy regardless of stone size, stone location, or the presence of bile duct stricture.

Malignant pheochromocytoma. Chromaffin granule transmitters and response to treatment

Chromaffin granule transmitters such as chromogranin A and catecholamines have been used in the diagnosis of pheochromocytoma, but the diagnostic and prognostic value of chromogranin A have not been explored in malignant pheochromocytoma. We evaluated these transmitters in patients with pheochromocytoma (n=27), both benign (n=13) and malignant (n=14). Patients with benign pheochromocytoma were studied before and after surgical excision (n=6), whereas patients with malignant pheochromocytoma were evaluated before and after combination chemotherapy with regular cycles of cyclophosphamide/dacarbazine/vincristine (nonrandomized trial in n=9). During treatment, patient responses to chemotherapy were divided according to anatomic and clinical criteria: responders (n=5) versus nonresponders (n=4). Plasma chromogranin A rose progressively (P<0.0001) from control subjects (48.0+/-3.0 ng/mL) to benign pheochromocytoma (188+/-40.5 ng/mL) to malignant pheochromocytoma (2932+/-960 ng/mL). Parallel changes were seen for plasma norepinephrine (P<0.0001), though plasma epinephrine was actually lower in malignant than benign pheochromocytoma (P=0.0182). In bivariate analyses, chromogranin A, norepinephrine, and epinephrine discriminated between pheochromocytoma and control subjects (all P<0.0001), whereas in a multivariate analyses, norepinephrine was the best discriminator (P:=0.011). Chromogranin A was significantly different in benign versus malignant pheochromocytoma on both bivariate (P=0.0003) and multivariate (P:=0.011) analyses. After excision of benign pheochromocytoma, chromogranin A (P=0.028), norepinephrine (P=0.047), and epinephrine (P=0.037) all fell to values near normal. During chemotherapy of malignant pheochromocytoma (n=9), plasma chromogranin A (P=0.047) and norepinephrine (P=0.02) fell but not epinephrine. In 5 responders to chemotherapy, there were significant declines in chromogranin A (P=0.03) and norepinephrine (P=0.03) but not epinephrine; in 4 nonresponders, none of the transmitters changed. Plasma chromogranin A varied longitudinally with tumor response and relapse. We conclude that plasma chromogranin A is an effective tool in the diagnosis of pheochromocytoma, and markedly elevated chromogranin A may point to malignant pheochromocytoma. During chemotherapy of malignant pheochromocytoma, chromogranin A can be used to gauge tumor response and relapse.

Oral absorption of clarithromycin in acute illness and during convalescence in patients with community-acquired pneumonia

STUDY OBJECTIVE

To compare the extent of oral clarithromycin absorption in patients during an illness and in health.

DESIGN

Sequential two-phase prospective study including an acutely ill pneumonia phase (PP) and a subsequent convalescent phase (CP).

STUDY POPULATION

Patients >/= 18 years old with radiographically confirmed community-acquired pneumonia (CAP) who were admitted to the hospital.

METHODS

During both study phases, patients received one single 500-mg dose of oral clarithromycin. Serial blood samples were drawn over a 24-h period in order to characterize the plasma concentration-time curves. Area under the curve from zero to 24 h (AUC(0-24)), maximum plasma concentration (Cmax), and time to maximum concentration (Tmax) were determined for both clarithromycin and its metabolite, 14-hydroxyclarithromycin, and compared between the two phases.

RESULTS

Twelve patients completed both phases of the study. For clarithromycin, there was a significant increase AUC(0-24) (47.37 +/- 8.51 microg/h/mL vs 36.22 +/- 6.09 microg/h/mL) in favor of the PP. There were no significant differences detected with respect to Cmax (4.32 +/- 0.63 microg/mL vs 3.57 +/- 0.46 microg/mL), or Tmax (3.50 +/- 0.50 h vs 2.83 +/- 0.59 h) between PP and CP. For 14-hydroxyclarithromycin, the AUC(0-24) and Cmax were significantly higher (5.84 +/- 1.08 microg/h/mL vs 8.84 +/- 1.92 microg/h/mL; 0.42 +/- 0.08 microg/mL vs 0.76 +/- 0.23 microg/mL) in the CP as compared to the PP. Tmax remained unchanged.

CONCLUSION

The extent of absorption of oral clarithromycin was not diminished during an acute illness with CAP.

Follow-up study of depression in the elderly. Clinical and SPECT data

BACKGROUND

Imaging studies in depression of the elderly are often small and highly selective.

AIMS

To investigate a large group of elderly depressed patients in order to assess changes in clinical, imaging and neuropsychological variables at follow-up.

METHOD

Patients (n = 175, age range 65-91 years) with clinical depression were identified from consecutive local referrals. Clinical interviews, neuropsychological tests and SPECT scans were carried out at referral and at two-year follow-up.

RESULTS

Of 84 re-examined patients, 46.5% were well, 9.5% were ill, 33% partially recovered and 11% had developed dementia. Duration of illness before index assessment was the only factor to predict outcome. Thirty-nine patients could be scanned and followed up. There were no differences between patients with good or poor depressive outcome on SPECT. Ten clinically improved patients could be re-examined with SPECT. There were relative increases in right cingulate gyrus and right cerebellum at follow-up.

CONCLUSIONS

The patients group was comparable with other studies showing high levels of residual depressive symptoms. Activity changes in limbic cortex are implicated in depression of old age.

Comparison of ear to rectal temperature measurements in infants and toddlers

The purpose of this study was to compare arterial heat balance ear temperature measurements to rectal temperatures in infants and children and to determine the ability of the ear thermometer being tested to detect fever. From 12/95 to 2/96, 1,175 pairs of ear and rectal temperature measurements were prospectively obtained from 140 infants and toddlers. The mean rectal temperature was 37.58 degrees C (sd = 0.68) and the mean ear temperature was 37.60 degrees C (sd = 0.85). However, at the low end of the rectal temperature scale, ear temperatures tended to be higher, and at the high end of the rectal temperature scale, ear temperatures tended to be lower. There were 292 readings with a rectal temperature > or = 38.0 degrees C and in 204 (70%) the ear temperature was also > or = 38.0 degrees C. A retrospective analysis of 53 children who became febrile in hospital (ear or rectal temperature > or = 38.0 degrees C) showed that fever was detected first by rectal measurement in seven, by ear measurement in 31 (59%), and by both in 15 (28%). These data indicate that, on the average, rectal and ear temperature measurements are not different. Fever that developed in children after hospitalization was more likely to be first detected by ear than by rectal measurement.

Azithromycin versus ciprofloxacin for treatment of uncomplicated typhoid fever in a randomized trial in Egypt that included patients with multidrug resistance

To compare clinical and bacteriological efficacies of azithromycin and ciprofloxacin for typhoid fever, 123 adults with fever and signs of uncomplicated typhoid fever were entered into a randomized trial. Cultures of blood were positive for Salmonella typhi in 59 patients and for S. paratyphi A in 3 cases; stool cultures were positive for S. typhi in 11 cases and for S. paratyphi A in 1 case. Multiple-drug resistance (MDR; resistance to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole) was present in isolates of 21 of 64 patients with positive cultures. Of these 64 patients, 36 received 1 g of azithromycin orally once on the first day, followed by 500 mg given orally once daily on the next 6 days; 28 patients received 500 mg of ciprofloxacin orally twice daily for 7 days. Blood cultures were repeated on days 4 and 10 after the start of therapy, and stool cultures were done on days 4, 10, and 28 after the start of therapy. All patients in both groups improved during therapy and were cured. Defervescence (maximum daily temperatures of </=38 degrees C) occurred at the following times [mean +/- standard deviation (range)] after the start of therapy: 3.8 +/- 1.1 (2 to 7) days with azithromycin and 3.3 +/- 1.0 (1 to 5) days with ciprofloxacin. No relapses were detected. Cultures of blood and stool during and after therapy were negative in all cases, except for one patient treated with azithromycin who had a positive blood culture on day 4. These results indicated that azithromycin and ciprofloxacin were similarly effective, both clinically and bacteriologically, against typhoid fever caused by both sensitive organisms and MDR S. typhi.

Pain after primary inguinal herniorrhaphy: influence of surgical technique

BACKGROUND

Pain is an important problem after ambulatory hernia repair. To assess the influence of the surgical technique on postoperative pain, two separate randomized, patient-blinded, controlled trials were performed in men with an indirect inguinal hernia.

STUDY DESIGN

In study A, 48 patients with an internal inguinal ring smaller than 1.5 cm were randomly allocated to either simple extirpation of the hernial sac or extirpation plus annulorrhaphy. In study B, 84 patients with an internal inguinal ring wider than 1.5 cm were randomly allocated to extirpation plus annulorrhaphy or extirpation plus Lichtenstein mesh repair (modified). All operations were performed under unmonitored local anesthesia with standardized perioperative analgesia using methadone and tenoxicam. Pain was scored daily for the first postoperative week and after 4 weeks on a four-point verbal-rank scale (no, light, moderate, or severe pain) during rest, while coughing, and during mobilization (rising to the sitting position). Use of supplementary analgesics (paracetamol) was recorded. Cumulative daily pain scores for the first postoperative week and the number of patients who used supplementary analgesics were the main outcome measures.

RESULTS

There were no significant differences in cumulative pain scores or use of supplementary analgesics between the treatment groups in either study. Cumulative pain scores were significantly higher during coughing and mobilization than during rest in both studies.

CONCLUSIONS

Choice of surgical technique for open repair of a primary indirect inguinal hernia has no influence on postoperative pain.

The incidence of fetal heart rate changes after intrathecal fentanyl labor analgesia

We performed a retrospective review to compare the incidence of new fetal heart rate abnormalities after institution of either intrathecal fentanyl or conventional epidural labor analgesia. In chronological order, the first 100 parturients in active labor who had received epidural analgesia and had recorded fetal heart rate (FHR) traces for 30 min before and after injection were identified, as were the first 100 parturients who had received intrathecal fentanyl analgesia. A perinatologist blinded to the anesthetic technique evaluated each recording and identified any changes in the FHR between the before and after tracings. The incidence of new "negative" (implying worsened fetal status) changes was 6% in the epidural group and 12% in the intrathecal group (P > 0.05, not significant). There were no differences in incidence or degree of blood pressure change, need for cesarean delivery, neonatal outcome, parity, or oxytocin use. No parturient required urgent or emergent cesarean delivery, and all changes resolved within the 30-min observation period. A much larger study would be required to determine whether this six percentage point difference represents a true difference between groups, and its clinical significance.

IMPLICATIONS

We compared the incidence of fetal heart rate changes after two techniques of labor analgesia. Both techniques were associated with a low (6%-12%) incidence of changes, but a much larger series would be required to determine whether this represents a true difference. No difference in neonatal outcome was found.

Growth hormone response to baclofen in patients with seasonal affective disorder: effects of light therapy

There is evidence for gamma-aminobutyric acid (GABA) dysfunction in the pathophysiology and treatment response of patients with major depression, but this has not been studied in seasonal affective disorder (SAD). Growth hormone (GH) response to a challenge with a GABAB receptor agonist, baclofen, is considered an in vivo index of hypothalamic GABAB receptor function in humans. To explore the role of GABAB receptor function in SAD, we compared the GH response to baclofen challenge in 15 patients with SAD and 20 matched healthy controls. Of the 15 patients with SAD, 14 had repeat baclofen challenge following 2-week treatment with light therapy. The results showed that baclofen administration led to a significant increase in GH release both in patients with SAD and normal controls. There was no significant difference in the GH response to baclofen between the two groups. Furthermore, 2-week treatment with light therapy did not significantly alter the baclofen-induced GH response in patients with SAD, in spite of a clear therapeutic effect. The results of this study suggest that hypothalamic GABAB receptor function, as measured by baclofen induced GH release, is not altered in patients with SAD or by light therapy.

Sample size and power calculations for comparing two independent proportions in a 'negative' trial

Statistical methods for evaluating the adequacy of sample size and power cater mainly to the testing for treatment difference in a 'positive' trial. In biomedical research, the trial can sometimes be postulated as 'negative' to demonstrate that the different treatment groups are statistically equivalent. Herein we describe a computer program to determine the adequacy of sample size and power for comparing two independent proportions in a 'negative' trial. The program is written in MicroSoft QuickBasic Version 4.5, and its executable file is suitable for use as a stand-alone program on a microcomputer.

Ultrastructural effects of intravascularly injected polyethylene glycol-hemoglobin in intestinal mucosa

Polyethylene glycol (PEG)-conjugated Hb (PEG-Hb) is being considered as a blood substitute. Previously, we showed that PEG-Hb extravasates rapidly from the intestinal mucosa and causes transient epithelial sloughing, resulting in temporary unimpeded passage of material between the intestinal lumen and the microcirculation. The present study quantifies the time course of factors related to this disturbance. Anesthetized Sprague-Dawley rats (350-450 g) were injected with a bolus of PEG-Hb (10 mg/ml) in saline. Control animals received saline, alone or with Dextran 70 (5 mg/ml). After 2, 8, 15, 60, or 90 min, the small intestine was perfusion fixed for microscopy (4 animals for each time point). Epithelial cell detachment and mucosal mast cell degranulation peaked at 2 and 8-15 min, respectively, but by 90 min were back to normal. Goblet cell secretion increased with time up to 8-15 min, after which it leveled off. Mean interstitial width was significantly greater 8 min after injection than for controls and continued to increase with time. In capillaries, endothelial fenestral diaphragms were replaced by thick, amorphous structures. Mesenteric mast cell degranulation was significantly greater 60-90 min after injection compared with controls. We propose that these results are consistent with intravascular injection of PEG-Hb invoking a transient inflammatory response in the intestine.

Expression of altered alpha2-adrenergic phenotypic traits in normotensive humans at genetic risk of hereditary (essential) hypertension

BACKGROUND

Essential (hereditary) hypertension is a common, though complex, trait with substantial heritability, but a still-obscure mode of inheritance. In this disorder with relatively late onset, knowledge of phenotypes with earlier penetrance would aid genetic analyses, as well as assessment of risk.

OBJECTIVE

Because alpha2-adrenergic receptor alterations are among the most heritable in experimental genetic hypertension, we hypothesized enhanced expression of alpha2-adrenergic phenotypic traits in still-normotensive humans at genetic risk of hypertension.

METHODS

We evaluated hemodynamic (blood pressure, cardiac output, systemic vascular resistance, stroke volume, and cardiac contractility) and biochemical (plasma drug, catecholamine, renin, and chromogranin A levels) responses to alpha2-adrenergic blockade with intravenous yohimbine in 84 normotensive subjects stratified by genetic risk of essential hypertension (67 with positive family histories and 17 with negative family histories of hypertension), as well as 18 subjects with established essential hypertension. Results were evaluated by analysis of variance, normal likelihood ratio test, and by maximum likelihood analysis for bimodality (i.e. mixtures) of response distributions.

RESULTS

Blood pressure rose (P<0.001) during alpha2-adrenergic blockade, with greater response (P<0.001) in members of the hypertensive than in members of the normotensive group. Hemodynamically, the rise in blood pressure resulted from an increase in cardiac output (P<0.001), with associated increases in stroke volume (P=0.002) and cardiac contractility (P=0.006), without an overall change in systemic vascular resistance. Biochemically, plasma norepinephrine (P<0.001), epinephrine (P=0.001), and chromogranin A (P=0.02) rose, suggesting augmentation of efferent exocytotic sympathoadrenal activity. Cardiac output and stroke volume responses were correlated to increments in plasma catecholamines (especially epinephrine) for the positive group, but not for the negative group. Baseline plasma catecholamines predicted increments of stroke volume after administration of yohimbine (P=0.003-0.007) for the positive but not for the negative group. Simultaneous comparison of means and variances of cardiac output and stroke volume alpha2-adrenergic responses, by using a normal likelihood ratio test, revealed highly significant (P=0.025 to P<0.0001) differences between the groups of subjects with and without family histories of hypertension. Frequency histogram suggested that there was a bimodal distribution of responses of stroke volume to alpha2-adrenergic blockade for the normotensive group with positive family histories of hypertension; maximum likelihood analysis strongly rejected the hypothesis of a unimodal distribution, whereas the hypothesis of bimodality could not be rejected (chi2=18.4, P=0.0004). The second (exaggerated) mode of response of stroke volume to alpha2-adrenergic blockade, defined by maximum likelihood analysis, was found for 9.5% of subjects in the normotensive group with positive family histories of hypertension, and was characterized by significantly different responses of cardiac output (P=0.001), stroke volume (P<0.001), contractility (P<0.001), heart rate (P=0.03), systemic vascular resistance (P<0.001), and epinephrine (P<0.001). Even prior to alpha2-adrenergic blockade, baseline stroke volume (P=0.01), heart rate (P=0.04), systemic vascular resistance (P=0.005), and catecholamine (P=0.001-0.005) values for this subgroup were different than control values.

CONCLUSIONS

We conclude that heterogeneous, bimodally distributed hemodynamic responses to alpha2-adrenergic blockade in subjects with positive family histories of hypertension suggest a discrete subgroup with early expression of perhaps Mendelian traits associated with risk of later development of hypertension. Such phenotypic traits ('intermediate phenotypes'), with earlier penetrance than hypertension itself, can be

Randomised controlled double-blind trial of the calcium channel antagonist amlodipine in the treatment of acute alcoholic hepatitis

BACKGROUND/AIMS

Calcium channel blockers have a hepatoprotective action in animal models of alcohol-induced liver injury but their effect in alcoholic liver disease in humans has not been previously investigated. We have conducted a randomised, placebo-controlled trial to investigate the possible benefit of the calcium channel blocker amlodipine in terms of 4-week survival in hospitalised patients with severe acute alcoholic hepatitis.

METHODS

Sixty-two patients with acute alcoholic hepatitis were randomised to receive 5-10 mg amlodipine each day for 1 year or an identical capsule containing placebo. In 36 (58%), acute alcoholic hepatitis was confirmed on biopsy and in the remainder on clinical and laboratory criteria. There were no statistically significant differences in clinical characteristics and disease severity in the treated and placebo groups.

RESULTS

Of the 32 patients receiving amlodipine, there were six deaths (19%) in the first 4 weeks compared with seven (23%) of the placebo patients (p=0.329). Causes of death were similar in the amlodipine and control groups, with liver failure predominant. Analysis by the Cox proportional hazards model after adjustment for other prognostic factors showed survival was not significantly influenced by active treatment (p=0.07). One patient in each group was withdrawn because of the development of hypotension, but this did not recur on reintroduction of the capsules.

CONCLUSIONS

This study shows that calcium channel blockers are well tolerated with few side effects in advanced alcoholic liver disease, but there is no conclusive evidence from this study that calcium channel blockers are helpful in the treatment of alcoholic hepatitis.

The seven habits of highly effective data users

Effective data interpretation is a habit, not a random event. By applying the seven habits outlined in this article, any otolaryngologist--regardless of the level of statistical knowledge or lack thereof--will be able to use data effectively. The seven habits are (1) check quality before quantity, (2) describe before you analyze, (3) accept the uncertainty of all data, (4) measure error with the right statistical test, (5) put clinical importance before statistical significance, (6) seek the sample source, and (7) view science as a cumulative process. The same habits apply whether interpreting one's own data, interpreting someone else's data, reviewing an unpublished manuscript for a journal, or reviewing a grant application for a funding agency. The basic principles that underlie these habits provide a systematic process for moving from observations to generalizations with predictable degrees of certainty--and uncertainty.

Prospective placebo-controlled randomized trial of lexipafant in predicted severe acute pancreatitis

BACKGROUND

Many patients with severe acute pancreatitis develop organ system failure during the first few days of illness, and this accounts for the majority of early deaths. No specific therapy is available and treatment remains supportive.

METHODS

In a randomized controlled trial conducted in 11 hospitals in the West of Scotland, 50 patients with predicted severe acute pancreatitis were selected from 188 screened over a 14-month period. Patients received placebo or lexipafant, a potent platelet-activating factor antagonist, by continuous intravenous infusion at a dose of 100 mg/day for up to 7 days. Early systemic complications were assessed by the measurement of organ failure scores.

RESULTS

There was a significantly greater fall in organ failure score in the treatment group during the 7 days of study (mean and median changes in organ failure score were 0.17 and 0 in the placebo group versus -1.42 and -1 in the treatment group; P = 0.003, Wilcoxon rank sum test), associated with trends towards a reduction in mortality and a reduced incidence of systemic complications.

CONCLUSION

These results suggest that lexipafant may be a useful adjunct to full supportive care in the early management of patients with severe acute pancreatitis.

Prospective placebo-controlled randomized trial of lexipafant in predicted severe acute pancreatitis

BACKGROUND

Many patients with severe acute pancreatitis develop organ system failure during the first few days of illness, and this accounts for the majority of early deaths. No specific therapy is available and treatment remains supportive.

METHODS

In a randomized controlled trial conducted in 11 hospitals in the West of Scotland, 50 patients with predicted severe acute pancreatitis were selected from 188 screened over a 14-month period. Patients received placebo or lexipafant, a potent platelet-activating factor antagonist, by continuous intravenous infusion at a dose of 100 mg/day for up to 7 days. Early systemic complications were assessed by the measurement of organ failure scores.

RESULTS

There was a significantly greater fall in organ failure score in the treatment group during the 7 days of study (mean and median changes in organ failure score were 0.17 and 0 in the placebo group versus -1.42 and -1 in the treatment group; P = 0.003, Wilcoxon rank sum test), associated with trends towards a reduction in mortality and a reduced incidence of systemic complications.

CONCLUSION

These results suggest that lexipafant may be a useful adjunct to full supportive care in the early management of patients with severe acute pancreatitis.

Cardiopulmonary function at rest and during exercise after resection for bronchial carcinoma

BACKGROUND

Measurements of postoperative spirometric values after pneumonectomy and lobectomy vary considerably, and few researchers have studied the changes in exercise capacity during maximal work after lung resection. The purpose of this study was to describe the postoperative alterations in cardiopulmonary function.

METHODS

Ninety-seven consecutive patients with lung malignancy were prospectively examined with maximal exercise test, spirometry, and arterial gas tensions. Fifty-seven patients were reinvestigated 6 months postoperatively.

RESULTS

In patients having lobectomy, forced expiratory volume in 1 second decreased 8%, and exercise capacity, expressed by maximal oxygen uptake and maximal work rate, significantly decreased 13%. In patients having pneumonectomy forced expiratory volume in 1 second significantly decreased 23%, but the loss in lung volume was partly compensated as measured by exercise capacity, which decreased only 16%. Generally patients with the smallest preoperative forced vital capacity had the smallest postoperative deterioration expressed in percentages. We found a weak correlation between alterations in maximal oxygen uptake and lung function after resection.

CONCLUSIONS

Lobectomy is associated with only minor deterioration of lung function and exercise capacity. Pneumonectomy causes a decrease in pulmonary volumes to about 75% of the preoperative values, partly compensated in better oxygen uptake, which postoperatively was about 85% of the preoperative values. Alteration in forced expiratory volume in 1 second is a poor predictor of change in exercise capacity after pulmonary resection.

Effect of lamotrigine on carbamazepine epoxide/carbamazepine serum concentration ratios in adult patients with epilepsy

Although lamotrigine (LTG) appears to have a low propensity to cause pharmacokinetic interactions with other medications, it has been suggested that LTG may interfere with the elimination of carbamazepine 10,11-epoxide (CBZE), the active metabolite of carbamazepine (CBZ). Evidence for this pharmacokinetic interaction is inconclusive and conflicting, however. We evaluated CBZ apparent oral clearance and the steady-state CBZE/CBZ serum concentration ratios in nine patients (30.8 +/- 7.7 years) with epilepsy prior to and following the initiation of adjunctive treatment with LTG. Overall, CBZ oral clearance was unchanged following the introduction of LTG (5.58 +/- 1.60 vs. 5.81 +/- 1.74 1/h, P = 0.630). Likewise, CBZE to CBZ serum concentration ratios were not significantly different (0.241 +/- 0.082 vs. 0.232 +/- 0.082, P = 0.782). These observations suggest that the addition of LTG did not result in a significant pharmacokinetic interaction involving either CBZ or CBZE.