Variation in access to sugar-sweetened beverages in vending machines across rural, town and urban high schools

OBJECTIVES

The 2010 Dietary Guidelines for Americans include reducing consumption of sugar-sweetened beverages. Among the many possible routes of access for youth, school vending machines provide ready availability of sugar-sweetened beverages. The purpose of this study was to determine variation in high school student access to sugar-sweetened beverages through vending machines by geographic location - urban, town or rural - and to offer an approach for analysing school vending machine content.

STUDY DESIGN

Cross-sectional observational study.

METHODS

Between October 2007 and May 2008, trained coders recorded beverage vending machine content and machine-front advertising in 113 machines across 26 schools in New Hampshire and Vermont, USA.

RESULTS

Compared with town schools, urban schools were significantly less likely to offer sugar-sweetened beverages (P = 0.002). Rural schools also offered more sugar-sweetened beverages than urban schools, but this difference was not significant. Advertisements for sugar-sweetened beverages were highly prevalent in town schools.

CONCLUSIONS

High school students have ready access to sugar-sweetened beverages through their school vending machines. Town schools offer the highest risk of exposure; school vending machines located in towns offer up to twice as much access to sugar-sweetened beverages in both content and advertising compared with urban locations. Variation by geographic region suggests that healthier environments are possible and some schools can lead as inspirational role models.

Regional anesthesia meets ultrasound: a specialty in transition

Despite its well-known benefits, regional anesthesia has not attained the stature, simplicity, and safety of general anesthesia. Many of the challenges and clinical failures of regional anesthetic techniques can be attributed to fact that neurovascular anatomy is highly variable. Furthermore, current nerve localization techniques provide little or no information regarding the anatomical spread local anesthesia. Recently, ultrasound technology has been utilized by anesthesiologists in an attempt to minimize many of the drawbacks of traditional nerve block techniques. This review article will update the reader on the current status of ultrasound-guided regional anesthesia, provide an evidence-based context, and supply key facts regarding ultrasound physics. In the process, we will also highlight several possible limitations of ultrasound techniques including learning curve issues, costs, and artifact generation.

Children with a TV in their bedroom at higher risk for being overweight

OBJECTIVE

We examined having a TV in the bedroom as a risk factor for child overweight.

DESIGN

Cross-sectional study.

SETTING

School- and telephone-based surveys in New Hampshire and Vermont between 2002 and 2004.

PARTICIPANTS

Two thousand three hundred and forty-three children enrolled in public schools, aged 9-12 years, and one of their parents.

MAIN EXPOSURES

The child having a TV in the bedroom.

MAIN OUTCOME MEASURES

Age- and gender-standardized child body mass index (zBMI). Overweight was defined as equal to or above the 95th percentile for zBMI.

RESULTS

Overall, 22.3% (N=523) of the children were overweight, and almost half of all children (48.2%, N=1130) had a TV in their bedroom. Children with a TV in their bedroom had a higher zBMI and were significantly more likely to be overweight compared to those without a TV in their bedroom (27.3 versus 17.7%, respectively; P<0.05). After controlling for sociodemographics, physical activity, frequency of TV or movie watching and internet use, children with a TV in their bedroom who watched at least one session of TV or movies per day were more likely to be overweight compared to those without a TV in their bedroom (odds ratio=1.32, 95% confidence interval: 1.03, 1.70).

CONCLUSIONS

Having a TV in the bedroom is a risk factor for child overweight, independent of reported physical activity, participation in team sports, TV or movie watching time and internet use at home. Further study is needed to fully understand the mechanism by which having a TV in the bedroom increases children's risk for overweight.

Ultrasound guidance improves the success rate of a perivascular axillary plexus block

BACKGROUND

Traditional approaches to performing brachial plexus blocks via the axillary approach have varying success rates. The main objective of this study was to evaluate if a specific technique of ultrasound guidance could improve the success of axillary blocks in comparison to a two injection transarterial technique.

METHODS

Fifty-six ASA physical status I-III patients presenting for elective hand surgery were prospectively randomized to receive an axillary block performed by either a transarterial technique (Group TA) or an ultrasound-guided perivascular approach (Group US). Both groups received a total of 30 ml of 1.5% lidocaine (225 mg) with 5 microg/ml epinephrine. Patients were then evaluated for block onset in specific nerve distributions and whether or not the block acted as a surgical anesthetic.

RESULTS

Group TA sustained more failures defined as conversion to general anesthesia or the inability to localize the artery [Group TA eight patients (29%) vs. Group US in which 0 patients required conversion to general anesthesia (0%) P < 0.01]. Group US demonstrated a reduction in performance times vs. Group TA (7.9 +/- 3.9 min vs. 11.1 +/- 5.7 min, P < 0.05). By 30 min post-injection, there were no significant differences between groups TA and US in terms of the proportion of patients demonstrating a complete motor or sensory loss.

CONCLUSION

Ultrasonographic guidance improves the overall success rate of axillary blocks in comparison to a transarterial technique.

Antimicrobial activity of LB10827, a new orally administered cephalosporin, tested against Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae

A new orally administered cephalosporin, LB10827, was compared to 16 other antimicrobial agents tested against Streptococcus pneumoniae (520 strains), Haemophilus influenzae (302 strains) and Moraxella catarrhalis (188 strains) by reference broth microdilution methods. LB10827 (MIC90, 0.12 mg/L; highest MIC, 0.5 mg/L) was 8-16-fold more potent than cefdinir, cefpodoxime or cefuroxime when tested against S. pneumoniae. All Gram-negative strains were inhibited at </= 0.5 mg/L LB10827, which is an activity equal or superior to that of currently available and tested oral beta-lactams. LB10827 appears to be a promising agent worthy of continued investigations both in vitro and in vivo.

Comparative antimicrobial spectrum and activity of BMS284756 (T-3811; a desfluoroquinolone) tested against an international collection of staphylococci and enterococci, including in vitro test development and intermethod comparisons

The study was initiated to determine the in vitro activity and MIC/disk test comparisons of BMS284756, a new des-fluoro(6)-quinolone, against isolates of staphylococci and enterococci from the SENTRY Antimicrobial Surveillance Program, 2000. Isolates were tested by reference broth microdilution and standardized disk diffusion methods. Against 3,789 strains of gram-positive cocci from the SENTRY Program (2000), the BMS284756 MIC90 and percentage susceptible at < or = 2 and < or = 4 microg/ml were: Staphylococcus aureus (4 microg/ml; 89.3 and 97.1%), coagulase-negative staphylococci (CoNS; 4 microg/ml; 86.1 and 96.0%) and enterococci (> 4 microg/ml; 62.0 and 76.2%). Also tested were selected staphylococci (300 strains) and enterococci (102 strains) by two standardized methods. The activity of BMS284756 was highly correlated with oxacillin resistance among staphylococci. Oxacillin-susceptible staphylococci were all inhibited by BMS284756 at < or = 0.5 microg/ml, whereas oxacillin-resistant strains required inhibitory concentrations of > or = 1 microg/ml. Excellent correlation was observed between the MIC and 5-microg disk zone diameter for staphylococci and enterococci (r=0.91 to 0.93). Among vancomycin-susceptible enterococci, 67% of Enterococcus faecalis, 25% of E. faecium, and 76% of other Enterococcus spp. isolates were inhibited by BMS284756 at < or = 2 microg/ml. All vancomycin-resistant enterococci (VRE; 11 E. faecalis and 15 E. faecium) were inhibited by > or = 2 microg/ml of BMS284756. Among the non-VRE, non-faecium enterococcal isolates (n=64), 62% were inhibited by < or = 0.5 microg/ml. BMS284756 showed excellent activity against oxacillin-susceptible staphylococci and moderate activity against enterococci other than VRE and E. faecium. Acceptable correlations were observed between MIC and disk test results for both tested genus groups.

Effect of seeing tobacco use in films on trying smoking among adolescents: cross sectional study

OBJECTIVE

To test the hypothesis that greater exposure to smoking in films is associated with trying smoking among adolescents.

DESIGN

Cross sectional survey of 4919 schoolchildren aged 9-15 years, and assessment of occurrence of smoking in 601 films.

SETTING

Randomly selected middle schools in Vermont and New Hampshire, USA.

MAIN OUTCOME MEASURE

Number of schoolchildren who had ever tried smoking a cigarette.

RESULTS

The films contained a median of 5 (interquartile range 1-12) occurrences of smoking. The typical adolescent had seen 17 of 50 films listed. Exposure to smoking in films varied widely: median 91 (49-152) occurrences. The prevalence of ever trying smoking increased with higher categories of exposure: 4.9% among students who saw 0-50 occurrences of smoking, 13.7% for 51-100 occurrences, 22.1% for 101-150, and 31.3% for >150. The association remained significant after adjustment for age; sex; school performance; school; parents' education; smoking by friend, sibling, or parent; and receptivity to tobacco promotions. The adjusted odds ratios of ever trying smoking for students in the higher categories of exposure, compared with students exposed to 0-50 occurrences of smoking in films, were 1.7 (95% confidence interval 1.2 to 2.4), 2.4 (1.7 to 3.4), and 2.7 (2.0 to 3.8). These odds ratios were not substantially affected by adjustment for parenting style or for personality traits of the adolescent.

CONCLUSION

In this sample of adolescents there was a strong, direct, and independent association between seeing tobacco use in films and trying cigarettes, a finding that supports the hypothesis that smoking in films has a role in the initiation of smoking in adolescents.

Spectrum and activity of three contemporary fluoroquinolones tested against Pseudomonas aeruginosa isolates from urinary tract infections in the SENTRY Antimicrobial Surveillance Program (Europe and the Americas; 2000): more alike than different!

The spectrum and potency of ciprofloxacin, gatifloxacin and levofloxacin was compared to that of 10 other agents against urinary tract isolates of Pseudomonas aeruginosa among patients in the year 2000 SENTRY Antimicrobial Surveillance Program (Europe, Latin America, North America). Dramatic differences were observed between isolates in geographic areas with the most fluoroquinolone-resistant strains detected in Latin America (54.5% resistance) compared to resistance rates of 40.8-43.7% and 28.3-29.2% for Europe and North America, respectively. Overall, no significant differences were observed between the spectrums of these fluoroquinolones (37.1-38.8% resistance) for therapy of P. aeruginosa urinary tract infections in hospitalized patients. Generally, in this world wide sample, aminoglycosides, carbapenems (imipenem, meropenem), cefepime, and piperacillin with or without tazobactam possessed a wider range of activity and spectrum versus current P. aeruginosa clinical isolates.

Comparative antimicrobial spectrum and activity of BMS284756 (T-3811, a desfluoroquinolone) tested against 656 Enterobacteriaceae, including preliminary in vitro susceptibility test comparisons and development

BMS284756 (T-3811), a novel des-F(6)-quinolone, was evaluated using isolates of Enterobacteriaceae from the SENTRY Antimicrobial Surveillance Program tested by Etest (AB BIODISK, Solna, Sweden), reference broth microdilution and disk diffusion (5-microg) methods. Ciprofloxacin, levofloxacin, gemifloxacin and gatifloxacin were also tested by broth microdilution as comparator antimicrobial agents within the same drug class. The 656 isolate collection included species from the genera Citrobacter, Enterobacter, Escherichia, Hafnia, Klebsiella, Morganella, Pantoea, Proteus, Providencia, Salmonella, and Serratia. BMS284756 was slightly less active than comparison fluoroquinolones against these isolates (MIC(90), 4 mg/l versus 0.06-2 mg/l). However, at a proposed susceptible breakpoint of < or =4 mg/l, 90.7% of the isolates processed were susceptible to BMS284756, demonstrating an equivalent spectrum of activity to all other agents except gemifloxacin (86.6%). In general, isolates requiring >4 mg/l of BMS284756 for inhibition of growth were also less susceptible to the comparators suggesting cross-resistance is common between des-F(6)- and fluoro-quinolones. Excellent correlation was observed between broth microdilution MIC results and 5-microg disk zone diameters (r=0.94), and between broth microdilution dilution and Etest MIC values (r=0.96). In conclusion, BMS284756 has an activity and spectrum similar to contemporary fluoroquinolones and in vitro test methods (NCCLS, Etest) appear accurate and reproducible

In vitro antimicrobial activity of GAR-936 tested against antibiotic-resistant gram-positive blood stream infection isolates and strains producing extended-spectrum beta-lactamases

GAR-936, a new, semisynthetic glycylcycline, has shown good antibacterial activity against a wide range of clinically important Gram-positive and -negative aerobic bacteria including Streptococcus pneumoniae, Hemophilus influenzae, Moraxella catarrhalis, Neisseria gonorrhoeae, most Enterobacteriaceae, Staphylococcus aureus and Enterococcus spp. The purpose of this study was to determine the activity of GAR-936 against a range of Gram-positive and -negative bloodstream isolates including many strains producing extended-spectrum beta-lactamases (ESBLs). Six hundred four bloodstream isolates of Gram-positive cocci collected as part of the SENTRY surveillance program were selected for their geographic diversity. GAR-936 was also tested against an additional 176 Gram-negative cocci isolates (Klebsiella pneumoniae, 98 strains; Escherichia coli, 78 strains), 96 of which were ESBL-producers. Broth microdilution testing was used to determine the susceptibility of the selected organisms and a range of comparator antimicrobial agents whose choice was based on their activities against the selected pathogens and included a mix of both newer and older agents. Presence of an ESBL-producing strain was confirmed using the clavulanate test. GAR-936 demonstrated impressive activity against all 604 strains of Gram-positive cocci, with an MIC range of <or=0.015-1 microg/mL, and MIC(90)s ranging from <or=0.05 microg/mL for S. pneumoniae to 0.25 for S. aureus and coagulase-negative staphylococci. MICs against the 176 Gram-negative isolates were higher (range 0.06-4 microg/mL), with MIC(90)s of 0.25-1 microg/mL. The activity of GAR-936 was relatively unaffected by the presence of ESBLs. The activity of GAR-936 was particularly impressive against Gram-positive cocci when compared against the test results for vancomycin and the newer antimicrobial agents, linezolid and quinupristin/dalfopristin. The MIC(90)s for GAR-936 were significantly lower than the comparator agents for all species tested with particularly impressive results against S. pneumoniae and enterococci.

Flow dependency of error in thermodilution measurement of cardiac output during acute tricuspid regurgitation

OBJECTIVE

To evaluate the effect of variable degrees of tricuspid regurgitation on thermodilution cardiac output measurements during changes in venous return.

DESIGN

Prospective, controlled animal study.

SETTING

University laboratory.

PARTICIPANTS

Eight anesthetized mongrel dogs instrumented for simultaneous measurement of cardiac output by thermodilution and ascending aortic electromagnetometry.

INTERVENTIONS

Data were collected before and after induction of moderate and severe tricuspid regurgitation. Under each condition, measurements were obtained at baseline and after opening 2 peripheral arteriovenous shunts to increase venous return.

MEASUREMENTS AND MAIN RESULTS

Baseline electromagnetic flow ranged from 1.74 to 3.62 L/min (median 2.73 L/min). Moderate and severe regurgitation reduced median electromagnetic flow values by 31% and 51%. Applying generalized estimating equations to model thermodilution cardiac output as a function of electromagnetic flow, arteriovenous shunt, and severity of tricuspid regurgitation revealed that (1) moderate and severe regurgitation changed the slope and intercept of the thermodilution/electromagnetic regression, but the differences between them were not significant, and (2) arteriovenous shunt alone had no effect under any condition. A simplified model independent of shunt and containing just 2 levels of tricuspid regurgitation (none or present) crossed with electromagnetic flow was applied. This analysis showed that regurgitation caused thermodilution to significantly underestimate electromagnetic flow at cardiac outputs > 2.27 L/min (99 mL/kg/min) and overestimate it at flows < 1.02 L/min (44 mL/kg/min).

CONCLUSIONS

These data show that acute tricuspid regurgitation may produce underestimation of cardiac output by thermodilution when flow is relatively high, produce overestimation when flow is relatively low, or have minimal effect when flow is in the midrange.

Antimicrobial resistance in viridans group streptococci among patients with and without the diagnosis of cancer in the USA, Canada and Latin America

OBJECTIVE

To investigate antimicrobial resistance in viridans group streptococci (VGS) among patients with and without the diagnosis of cancer in the USA, Canada and Latin America.

METHODS

All bloodstream isolates of VGS collected from SENTRY centers in the Western Hemisphere between January 1997 and December 1999 were tested by reference broth microdilution methods (NCCLS). Results for isolates from patients with cancer were compared to those from other patient populations.

RESULTS

Overall, 438 unique patient bloodstream isolates of VGS were collected during the study. Percentage susceptible/MIC90 (mg/L) values for antimicrobials tested were as follows: penicillin, 66/1; erythromycin, 60/4; clindamycin, 92/0.12; cefepime, 86/1; trimethoprim-sulfamethoxazole, 80/2; ciprofloxacin, 44/> 2; gatifloxacin, 98/0.5; and vancomycin, 100/1. Of these isolates, 70 (16%) were confirmed to be from cancer patients. VGS isolates from cancer patients were less susceptible to most antimicrobials tested than were isolates from non-cancer patients. The greatest differences in susceptibility rates for cancer- versus non-cancer-associated VGS isolates were seen for ciprofloxacin (34% versus 46%, P = 0.07) and trimethoprim-sulfamethoxazole (64% versus 83%, P < 0.001), two agents which are often used for prophylaxis or as presumptive therapy in cancer patients.

CONCLUSIONS

Susceptibility rates for VGS isolates from cancer patients are lower than those for isolates from patients without a cancer diagnosis. These differences are greatest for agents that have seen widespread prophylactic and empirical use. Ongoing surveillance of VGS infections in this patient population is important and should help to guide therapy decisions.

Favourite movie stars, their tobacco use in contemporary movies, and its association with adolescent smoking

OBJECTIVE

To assess the relation between adolescents' favourite movie stars, the portrayal of tobacco use by those stars in contemporary motion pictures, and adolescent smoking.

DESIGN AND SETTING

632 students (sixth to 12th grade, ages 10-19 years) from five rural New England public schools completed a voluntary, self administered survey in October 1996. The survey assessed tobacco use, other variables associated with adolescent smoking, and favourite movie star. In addition, tobacco use by 43 selected movie stars was measured in films between 1994 and 1996.

OUTCOME MEASURES

Students were categorised into an ordinal five point index (tobacco status) based on their smoking behaviour and their smoking susceptibility: non-susceptible never smokers, susceptible never smokers, non-current experimenters, current experimenters, and smokers. We determined the adjusted cumulative odds of having advanced smoking status based on the amount of on-screen tobacco use by their favourite film star.

RESULTS

Of the 43 stars, 65% used tobacco at least once, and 42% portrayed smoking as an essential character trait in one or more films. Stars who smoked more than twice in a film were considered smokers. For adolescents whose favourite stars smoked in only one film, the odds of being higher on the smoking index was 0.78 (95% confidence interval (CI) 0.53 to 1.15). For adolescents whose favourite stars smoked in two films, the odds of being higher on the smoking index was 1.5 (95% CI 1.01 to 2.32). For adolescents whose favourite stars smoked in three or more films (Leonardo DiCaprio, Sharon Stone, John Travolta), the odds of being higher on the smoking index was 3.1 (95% CI 1.34 to 7.12). Among never smokers (n = 281), those who chose stars who were smokers in three or more films were much more likely to have favourable attitudes toward smoking (adjusted odds ratio 16.2, 95% CI 2.3 to 112).

CONCLUSIONS

Adolescents who choose movie stars who use tobacco on-screen are significantly more likely to have an advanced smoking status and more favourable attitudes toward smoking than adolescents who choose non-smoking stars. This finding supports the proposition that the portrayal of tobacco use in contemporary motion pictures, particularly by stars who are admired by adolescents, contributes to adolescent smoking.

Brand appearances in contemporary cinema films and contribution to global marketing of cigarettes

BACKGROUND

The appearance of a cigarette brand in a cinema film gives the brand a certain distinction through its association with the characters and general tone of the film. Through the worldwide distribution of films, brands are promoted globally. We assessed the tobacco-brand appearances in a 10-year sample of contemporary films.

METHODS

We viewed the contents of the top 25 US box-office films for each year of release, from 1988 to 1997 (250 films in total). We compared the prevalence of brand appearances for films produced before a voluntary ban on paid product placement by the tobacco industry (1988-90) with films produced after the ban (1991-97). Tobacco-brand appearance was defined as the screen appearance of a brand name, logo, or identifiable trademark on products or product packaging, billboards, store-front advertising, or tobacco promotional items. We defined actor endorsement of a brand as the display of a brand while being handled or used by an actor.

FINDINGS

More than 85% of the films contained tobacco use. Tobacco brands appeared in 70 (28%) films. Brand appearances were as common in films suitable for adolescent audiences as they were in films for adult audiences (32 vs 35%), and were also present in 20% of those rated for children. Prevalence of brand appearance did not change overall in relation to the ban. However, there was a striking increase in the type of brand appearance depicted, with actor endorsement increasing from 1% of films before the ban to 11% after. Four US cigarette brands accounted for 80% of brand appearances. Revenues outside the USA accounted for 49% of total revenues for these films, indicating a large international audience.

INTERPRETATION

Tobacco-brand appearances are common in films and are becoming increasingly endorsed by actors. The most highly advertised US cigarette brands account for most brand appearances, which suggests an advertising motive to this practice.

Respiratory tract pathogens isolated from patients hospitalized with suspected pneumonia: frequency of occurrence and antimicrobial susceptibility patterns from the SENTRY Antimicrobial Surveillance Program (United States and Canada, 1997)

Thirty-seven sentinel hospitals (29 in the United States [US]; eight in Canada) collected bacterial isolates from hospitalized patients with a diagnosis of pneumonia. The antimicrobial susceptibility patterns of these pathogens were determined to more than 60 agents (40 reported) using the reference broth microdilution method described by the National Committee for Clinical Laboratory Standards. The five most frequently recorded species among the 2757 isolates collected during the study were (no. tested/%): Staphylococcus aureus (632/22.9%), Pseudomonas aeruginosa (498/18. 1%), Haemophilus influenzae (284/10.3%), Klebsiella spp. (240/8.7%), and Streptococcus pneumoniae (213/7.7%). There was a significant difference in the susceptibility to antimicrobials between the US and Canada for S. aureus to oxacillin (50.1% versus 93.8% susceptible, respectively), gentamicin (78.7% versus 97.8%), and fluoroquinolones (49.5 to 53.0% versus 89.8 to 94.9%). Amikacin (92. 8% susceptible) was the most active antimicrobial agent against P. aeruginosa, and meropenem was the most potent beta-lactam. Against H. influenzae, most drugs retained a high level of activity, whilst against the S. pneumoniae, only the newer fluoroquinolones (gatifloxacin, levofloxacin, sparfloxacin) remained highly effective in vitro. Only two antimicrobial agents (imipenem and meropenem) were >99% active against the Klebsiella spp. and Enterobacter spp. isolated in this survey (possess extended spectrum beta-lactamases or hyperproduction of Amp C cephalosporins); cefepime (95.6-100.0% susceptible) was significantly more active than other cephalosporins tested. Clonal, epidemic outbreaks of multiply resistant strains were very rare in monitored hospitals. In conclusion, important differences exist between the US and Canada in the susceptibility patterns of some respiratory tract pathogens to commonly used antimicrobial agents with Canadian strains generally being more susceptible to currently available antimicrobial agents.

Antimicrobial activity and in vitro susceptibility test development for cefditoren against Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus species

Cefditoren, a third generation orally administered aminothiazolyl cephalosporin, has demonstrated bactericidal activity against many Gram positive and negative bacterial pathogens and stability against clinically important beta-lactamases. Cefditoren was compared to cefaclor, cefixime, and penicillins against 1 435 recently isolated strains of streptococci (312 Streptococcus pneumoniae, 165 viridans group streptococci, 142 beta-haemolytic streptococci), Haemophilus influenzae (521 strains), and Moraxella catarrhalis (295 strains). Streptococcus pneumoniae and viridans group streptococci had penicillin nonsusceptible rates of 37.8 and 35.8%, respectively. Cefditoren (MIC(90) in microg/ml/% susceptible) activity against all tested H. influenzae (0.03/100) and M. catarrhalis (0.06-0.5/100) was comparable to cefixime and significantly greater than cefaclor. Cefditoren (MIC(90), 0.5 microg/ml) was 4- to 128-fold more active than comparison beta-lactams against the pneumoococci and was the most potent beta-lactam (including penicillin) versus beta-haemolytic streptococci. Cefditoren pharmacokinetics demonstrate a T(1/2) of 1.5-2 h and C(max) values of 2.8 and 4.6 microg/ml, respectively with 200 or 400 mg doses of cefditoren pivoxil; plasma concentrations exceed 1 microg/ml for 4 to 6 hours (33-50% of dosing interval). Consequently, a susceptible MIC of </= 1 microg/ml or </= 2 microg/ml was proposed with zone diameter correlates of >/= 18 and >/= 15 mm (5-microg disk) for all cited fastidious species tested. Categorical agreement between MIC and disk tests was 94.6 to 100% with a correlation coefficient (r) range of 0.50 to 0.90 for streptococci. H. influenzae intermethod comparison results using the same interpretive criteria were in complete agreement, but exhibited a low r = 0.39. Cefditoren clearly possesses the most potent activity among currently studied oral cephalosporins or penicillin against commonly isolated bacterial pathogens causing bronchitis, pneumonia, sinusitis, or pharyngitis and was active against nearly all penicillin-resistant streptococci at </= 0.5 microg/ml. Expanded clinical investigations seem warranted.

Anti-gonococcal activity of gemifloxacin against fluoroquinolone-resistant strains and a comparison of agar dilution and Etest methods

Gemifloxacin is a novel quinolone with excellent activity against Gram-positive and some Gram-negative pathogens. Its activity was tested against 150 Neisseria gonorrhoeae strains, including 50 ciprofloxacin-resistant isolates, using reference agar dilution and Etest methods. Gemifloxacin was found to be highly potent against ciprofloxacin-susceptible strains (MIC(90) 0.008 mg/L), but was 16-fold less potent against ciprofloxacin-resistant gonococci. The order of quinolone potency against these fluoroquinolone-resistant mutants was: gemifloxacin (MIC(90) 0.12 mg/L) > trovafloxacin (0.25 mg/L) > moxifloxacin = grepafloxacin (0.5 mg/L) > ciprofloxacin (1 mg/L). Etest and reference agar dilution MIC results showed excellent correlation (r = 0.96) and >98% of MICs were within +/-1 log(2) dilution step (essential agreement). The excellent potency of gemifloxacin indicates its potential for the treatment of infections with quinolone-resistant N. gonorrhoeae.

Activity and spectrum of 22 antimicrobial agents tested against urinary tract infection pathogens in hospitalized patients in Latin America: report from the second year of the SENTRY antimicrobial surveillance program (1998)

The potency and spectrum of various antimicrobial agents tested against 434 bacterial isolates causing urinary tract infection (UTI) in hospitalized patients in Latin America were evaluated. The genotypes of the extended-spectrum beta-lactamase-producing and selected multi-resistant isolates were also evaluated by molecular typing techniques. Escherichia coli (60.4%) was the most common aetiological agent causing UTI, followed by Klebsiella spp. (11.2%) and Pseudomonas aeruginosa (8.3%). In contrast, Enterococcus spp. isolates caused only 2.3% of UTIs. Fewer than 50% of E. coli isolates were susceptible to broad-spectrum penicillins. The resistance rates to ciprofloxacin and the new quinolones were also high among these isolates. The molecular characterization of ciprofloxacin-resistant E. coli showed that most of them have a double mutation in the gyrA gene associated with a single mutation in the parC gene. The Klebsiella pneumoniae isolates studied demonstrated high resistance rates to beta-lactam drugs, including broad-spectrum cephalosporins. The carbapenems were the compounds with the highest susceptibility rate among these isolates (100.0% susceptible) followed by cefepime (91.7% susceptible). Meropenem, imipenem and cefepime were also the most active drugs against Enterobacter spp. Among P. aeruginosa isolates, meropenem (MIC(50), 2 mg/L) was the most active compound, followed by imipenem (MIC(50), 4 mg/L), cefepime (MIC(50), 8 mg/L) and ceftazidime (MIC(50), 16 mg/L). The results presented in this report confirm that bacterial resistance continues to be a great problem in Latin American medical institutions.

Trends in antimicrobial susceptibility of bacterial pathogens isolated from patients with bloodstream infections in the USA, Canada and Latin America. SENTRY Participants Group

From January through June of 1998, 4579 bloodstream infections (BSI) due to bacterial pathogens were reported from SENTRY hospitals in Canada, the USA and Latin America. Staphylococcus aureus, Escherichia coli, and coagulase-negative staphylococcus (CoNS) were the most common pathogens, together accounting for 55.2% of all BSI during this time period. Compared with the 5794 BSI reported from SENTRY from January through June of 1997, no major change was seen in the frequencies of occurrence of the most common bacterial causes of BSI. Between 1997 and 1998, the major change in antimicrobial resistance was an increase in oxacillin-resistance in both S. aureus and CoNS in all regions. These data demonstrate widespread antimicrobial resistance in Canada, Latin America and the USA, with a notable increase in oxacillin-resistance among staphylococci. Ongoing surveillance remains essential, and will enhance efforts to limit the scope of this worldwide problem.

Positive and negative outcome expectations of smoking: implications for prevention

BACKGROUND

To inform the development of messages for tobacco prevention programs, we examined seven positive and five negative outcome expectations of smoking as risk factors for smoking uptake.

METHODS

A cross-sectional, self-administered survey of 471 students in grades 6-12 who were never or experimental smokers was performed. Logistic regression was used to examine the relationship between outcome expectations and susceptibility to becoming a smoker in the future, a measure of intent and resistance to peer smoking.

RESULTS

A total of 36.1% of the sample was susceptible to smoking. All positive outcome expectations showed a strong and significant association with susceptibility. Students were most likely to be susceptible if they believed they would enjoy smoking (OR = 29.4). Three of the five negative outcome expectations were significantly associated with susceptibility, but the strength of these associations was much lower than that observed for the positive expectations (OR = 0.5 to 0.6). A strong belief in the negative outcomes of smoking did not alter the association between susceptibility and positive outcome expectations.

CONCLUSIONS

These findings suggest that teaching adolescents and teens about the negative consequences of smoking is unlikely to change their intent to smoke. Preventive efforts should identify ways to address the positive expectations adolescents have about smoking, possibly by offering alternative means for achieving these outcomes.

Antimicrobial activity of gatifloxacin (AM-1155, CG5501), and four other fluoroquinolones tested against 2,284 recent clinical strains of Streptococcus pneumoniae from Europe, Latin America, Canada, and the United States. The SENTRY Antimicrobial Surveillance Group (Americas and Europe)

The newer fluoroquinolones generally have greater potency against Gram-positive cocci including Streptococcus pneumoniae. In this study, we report the activity of gatifloxacin (formerly AM-1155 or CG5501) compared with penicillin, erythromycin, and four other peer drugs, tested against 2284 strains isolated in North America (Canada and United States), Latin America (six nations), and Europe in 1997. Reference broth microdilution methods were used and results were interpreted by consensus standards. Gatifloxacin demonstrated uniform potency against pneumococci across all monitored geographic areas (MIC90, 0.5 microgram/mL; > or = 99.6% of strains inhibited at < or = 1 microgram/mL). This activity was comparable to trovafloxacin (MIC90, 0.5 microgram/mL) and sparfloxacin (MIC90, 0.5 microgram/mL) and two- to four-fold greater than that of ciprofloxacin or levofloxacin. The most resistant strains to the fluoroquinolones had mutations in both par C (Ser 79-->Phe) and gyr A (Ser83-->Lys or Phe). Penicillin resistance (MIC, > or = 0.12 microgram/mL) rates varied from 27.6% in Europe to 55.7% in Latin America. Macrolide resistance was greatest in Europe and the United States. Gatifloxacin appears to be a promising new fluoroquinolone for clinical use in respiratory tract infections commonly caused by S. pneumoniae.

Comparative antimicrobial activity of gatifloxacin tested against Streptococcus spp. including quality control guidelines and etest method validation. Quality Control Study Group

Gatifloxacin (formerly AM-1155 or CG 5501) is a new 8-methoxy fluoroquinolone with enhanced activity against Gram-positive cocci, especially Streptococcus pneumoniae and other streptococci. Recent clinical strains (599 isolates) were tested against gatifloxacin, three comparison fluoroquinolones, and penicillin by the reference broth microdilution, Etest (AB BIODISK, Solna, Sweden) and standardized disk diffusion methods (5 micrograms gatifloxacin disk). Gatifloxacin (MIC90, 0.5 microgram/ml) activity was generally comparable to that of trovafloxacin (MIC90, 0.25 microgram/ml), or sparfloxacin (MIC90, 0.5 microgram/ ml) and markedly superior to ofloxacin (MIC90, 2-4 micrograms/ml) against the streptococci. Rates of penicillin non-susceptibility were 41.9, 38.0, and 16.2% for S. pneumoniae (301 strains), viridans group streptococci (150 strains), and beta-haemolytic streptococci (148 strains). Etest results correlated well (95.7-100.0% +/- one log2 dilution) with the reference MIC results, but Etest tended to have elevated gatifloxacin MIC results compared to the broth microdilution method for the highly resistant isolates (MICs, > 2 micrograms/ml). Gatifloxacin disk zone diameters correlate well to reference MICs for all streptococci and proposed interpretive criteria (susceptible at < or = 1 microgram/ml or > or = 18 mm, and resistant at > or = 4 micrograms/ml or < or = 14 mm) did not produce discords between method results (absolute agreement). A nine laboratory quality control (QC) study conforming to the National Committee for Clinical Laboratory Standards (NCCLS) Guideline M23-T3 studied S. pneumoniae ATCC 49619 and gatifloxacin. Proposed ranges for QC of NCCLS tests were 0.12-0.5 microgram/ml for the broth microdilution test and 24-31 mm for the disk diffusion method. These reported results indicate that gatifloxacin was a potent fluoroquinolone with extensive activity against streptococcal isolates. In vitro test methods to measure this activity appear accurate and comparable; and QC guidelines have been established for routine clinical laboratory use pending approval by the NCCLS and the Food and Drug Administration (FDA).

Activity of gatifloxacin against Haemophilus influenzae and Moraxella catarrhalis, including susceptibility test development, E-test comparisons, and quality control guidelines for H. influenzae

In vitro antimicrobial activity and susceptibility testing interpretation criteria and quality control were studied for gatifloxacin, a new 8-methoxy fluoroquinolone, tested against Haemophilus influenzae. Moraxella catarrhalis (600 strains) and H. influenzae (1,400 strains) from the SENTRY Antimicrobial Surveillance Program in North America (Canada and the United States) were also tested against gatifloxacin and 12 other antimicrobial agents. Gatifloxacin (MIC at which 90% of the isolates are inhibited [MIC90], </=0.03 microg/ml; 100.0% of strains inhibited at </=2 microg/ml) was the most active agent tested against H. influenzae and was similar to four comparison fluoroquinolones (MICs, </=0.03 to 2 microg/ml) against M. catarrhalis. A subset of 300 recent clinical isolates of H. influenzae were tested by using media (Haemophilus Test Medium agar and broth) and procedures recommended by the National Committee for Clinical Laboratory Standards (NCCLS) and with the E-test (AB BIODISK, Solna, Sweden). Gatifloxacin (MIC50, 0.008 microg/ml) was slightly more active than levofloxacin, and E-test results were generally elevated by 0.5 log2 dilution step compared to reference MICs. The gatifloxacin 5-microg disk test produced zone diameters that were routinely above 30 mm for H. influenzae strains, corresponding to gatifloxacin MICs of 0.008 or 0. 016 microg/ml. The gatifloxacin susceptibility breakpoint proposed for nonfastidious species (</=2 microg/ml; >/=18 mm) was also suggested for H. influenzae testing. No interpretive errors were observed. Quality control guidelines for H. influenzae ATCC 49247 were determined by using the NCCLS M23-T3 (1998) study design. The results from the nine-laboratory protocol suggested the following control ranges: for broth microdilution tests, 0.004 to 0.03 microg/ml; for disk diffusion testing, 33 to 41 mm. Gatifloxacin appears to be a potent anti-Haemophilus fluoroquinolone compound with in vitro testing interpretive criteria that will produce accurate results (disk diffusion, broth microdilution, and E-test).

Bacterial pathogens isolated from patients with skin and soft tissue infections: frequency of occurrence and antimicrobial susceptibility patterns from the SENTRY Antimicrobial Surveillance Program (United States and Canada, 1997). SENTRY Study Group (North America)

As part of the SENTRY Antimicrobial Surveillance Program, 1562 bacterial isolates were recovered from hospitalized patients with skin and soft tissue infections (SSTIs) in 30 United States (U.S.) and 8 Canadian medical centers between October and December, 1997. The overall rank order of recovery of the six most common pathogens was Staphylococcus aureus (42.6%) > Pseudomonas aeruginosa (11.3%) > Enterococcus spp. (8.1%) > Escherichia coli (7.2%) > Enterobacter spp. (5.2%) > beta-hemolytic streptocci (5.1%). With one exception, essentially the same order was observed in both the U.S. and Canada. The single exception was the Enterococcus group, which were the third most common isolate in the U.S. (9.6%), but the seventh most common isolate in Canada (3.7). Of note, 24.0% of S. aureus isolates were oxacillin resistant; vancomycin was uniformly active. Vancomycin resistance among Enterococcus spp. (16.5%) was observed only in the U.S. Several antimicrobial agents remained broadly active for SSTI isolates of P. aeruginosa, including meropenem, amikacin, tobramycin, and piperacillin with or without tazobactam. Imipenem resistance (MICs, > or = 8 micrograms/mL) was observed in 11.9% of isolates of P. aeruginosa and ceftazidime, and cefepime had equivalent activity (85.2% and 85.8% susceptible, respectively). Numerous beta-lactams, aminoglycosides and fluoroquinolones were broadly active against E. coli SSTI isolates (i.e. < 5% resistance). Extended-spectrum beta-lactamase production was uncommon both with E. coli and Klebsiella spp. in both nations. Cefepime, imipenem, and meropenem; the aminoglycosides; and fluoroquinolones were conspicuously more active against Enterobacter spp. than other agents tested. High-level, stably derepressed Amp C beta-lactamase production was commonly observed in this group (26.8%), but cefepime generally retained activity against these ceftazidime-resistant organisms. The results of this study serve to define the most common bacterial causes of SSTIs in North America, elucidate patterns of antimicrobial resistance and can be used as a basis for making initial empiric antimicrobial management decisions in hospitalized patients with such infections.

Survey of blood stream infections attributable to gram-positive cocci: frequency of occurrence and antimicrobial susceptibility of isolates collected in 1997 in the United States, Canada, and Latin America from the SENTRY Antimicrobial Surveillance Program. SENTRY Participants Group

The SENTRY Antimicrobial Surveillance Program was established in January, 1997 to monitor the predominant pathogens and antimicrobial resistance patterns of nosocomial and community-acquired infections via a network of sentinel hospitals in the United States (30 sites), Canada (eight sites), Latin America (10 sites), and Europe (24 sites). During the first 12-month study period (January to December, 1997), a total of 9519 blood stream infections (BSI) were reported by SENTRY participants in the U.S. (6150), Canada (1727), and Latin America (1642). The Gram-positive cocci, Staphylococcus aureus, coagulase-negative staphylococci (CoNS), enterococci, and streptococci accounted for 53.9% (5131 infections) of all BSI (56.5% U.S., 55.7% Canada, and 42.9% Latin America). The staphylococci, Enterococcus spp., S. pneumoniae, beta-hemolytic streptococci, and viridans group streptococci accounted for 6 of the top 11 BSI pathogens in the U.S. and Canada, whereas only S. aureus (1st), CoNS (3rd), and Enterococcus spp. (9th) were among the top 11 pathogens in Latin American hospitals. The results of this survey affirm the importance of Gram-positive cocci as causes of BSI in both North America and Latin America and demonstrate that important antimicrobial resistance exists among isolates of staphylococci, streptococci, and enterococci from all three geographic regions. This includes oxacillin-resistance among S. aureus (26.9% U.S., 29.2% Latin America, and 4.0% Canada) and CoNS (71.5% U.S., 68.4% Latin America, and 65.6% Canada), penicillin resistance among viridans group streptococci (48.5% U.S., 45.1% Canada, and 33.3% Latin America) and pneumococci (36.1% U.S., 27.5% Canada, and 65.6% Latin America), high-level resistance (HLR) to aminoglycosides among enterococci (27.2 to 70.1% U.S., 33.3 to 75.7% Canada and 16.7 to 51.5% Latin America), and macrolide resistance among beta-hemolytic streptococci (12.4 to 14.2% U.S., 10.5 to 12.3% Canada, and 0.0 to 4.0% Latin America), viridans group streptococci (32.4 to 39.7% U.S., 22.5-35.2% Canada, and 20.0% Latin America), and pneumococci (10.0 to 10.6% U.S., 9.8-10.8% Canada, and 9.4-18.7% Latin America). BSI isolates of Gram-positive cocci from the U.S. and Latin America were considerably more resistant than those from Canada. New agents with Gram-positive activity will be essential for optimal treatment of BSI attributable to Gram-positive cocci in both North and Latin America.

Comparison of activities of broad-spectrum beta-lactam compounds against 1,128 gram-positive cocci recently isolated in cancer treatment centers

We report the in vitro activities of broad-spectrum beta-lactam antimicrobials tested against 1,128 gram-positive pathogens recently isolated from cancer patients. Cefepime and imipenem were more active than ceftazidime and ceftriaxone against these organisms. Only vancomycin demonstrated reliable activity against oxacillin-resistant staphylococci, Enterococcus spp., and Corynebacterium spp. The spectrum of gram-positive organisms against which cefepime and imipenem have activity provides an advantage over ceftazidime as empiric therapy for cancer patients, potentially reducing the need for the empiric addition of glycopeptides.

Gatifloxacin (AM-1155, CG 5501) susceptibility testing interpretive criteria and quality control guidelines for dilution and disk (5-microgram) diffusion methods. The Quality Control Study Group

Gatifloxacin (formerly AM-1155 and CG5501), a new 8-methoxy fluoroquinolone, has an expanded spectrum of activity against Gram-positive cocci and some anaerobic bacteria. This compound was tested against 600 recent clinical strains of rapidly growing aerobic species to establish susceptibility testing interpretive criteria for the reference broth microdilution and standardized disk (5-microgram) diffusion methods of the National Committee for Clinical Laboratory Standards (NCCLS). These strains included 285 Enterobacteriaceae (17 species), 165 staphylococci, 49 enterococci, and 101 nonfermentative Gram-negative bacilli. Based on achievable serum levels with projected gatifloxacin dosing regimens, MIC break points of < or = 2 micrograms/mL (> or = 18 mm) for susceptibility and > or = 8 micrograms/mL (< or = 14 mm) for resistance were selected. The absolute agreement between tests was 94.3% with no very major false-resistant errors. The quality control ranges (MIC and zone diameters) for the NCCLS recommended strains were determined in a nine-laboratory NCCLS protocol as follows: Escherichia coli ATCC 25922 = 0.008-0.03 microgram/mL and 31-37 mm; Enterococcus faecalis ATCC 29212 = 0.12-1 microgram/mL; Pseudomonas aeruginosa ATCC 27853 = 0.5-2 micrograms/ml and 21-27 mm; Staphylococcus aureus ATCC 25923 = 27-33 mm and S. aureus ATCC 29213 = 0.03-0.12 microgram/mL. Gatifloxacin appears to be a promising new fluoroquinolone with acceptable susceptibility testing methods for routine clinical laboratory use.

Fracture risk in the U.S. Medicare population

Using data from the 5% U.S. Medicare sample, we estimated the actuarial (life table) risk that a person aged 65 will fracture the upper or lower limbs or the pelvis, by age 75, 80, 85, and 90, taking into account the chance of dying in the interval. The actuarial risk of a 65-year old white woman sustaining a fracture by age 90 is 16% for the hip, 9% for distal forearm, 5% for proximal humerus, and 4% for ankle. Black women and white men have substantially lower risks, and the risks for black men are very low. Although hip fractures pose the single greatest risk, the risk of all other fractures combined is greater. White women have particularly high risks for all fractures, because of their longevity as well as their high fracture rates. It is important to adjust for the probability of dying when estimating risks in an elderly population.

Antimicrobial activity of gatifloxacin tested against Neisseria gonorrhoeae using three methods and a collection of fluoroquinolone-resistant strains

Gatifloxacin, a new 8-methoxy fluoroquinolone, was tested against 131 strains of Neisseria gonorrhoeae by reference agar dilution, disk diffusion, and Etest (AB BIODISK, Solna, Sweden) methods on supplemented GC agar. Gatifloxacin activity was equal to ciprofloxacin (MIC50, 0.008 microgram/mL) against strains fully susceptible to fluoroquinolones, but was generally four-fold more active (MIC90, 0.064-0.094 microgram/mL) against strains with par C or gyr A mutations and resistance to ciprofloxacin. Etest results were comparable to those generated by the agar dilution test [correlation coefficient (r) = 0.97]. Gatifloxacin zone diameters using 5-microgram disks also correlated well (r = 0.86-0.87) with the agar dilution and Etest MIC results. Breakpoints for laboratory testing of Neisseria gonorrhoeae strains await clinical trial outcome correlations, but susceptibility at < or = 0.125 or < or = 0.25 microgram/mL (> or = 34 mm) seems appropriate. All three tests used in this study seem applicable for laboratory testing of isolates from patients with uncomplicated gonorrhoeae receiving therapy with gatifloxacin.

Antimicrobial activity of gatifloxacin tested against 1676 strains of ciprofloxacin-resistant gram-positive cocci isolated from patient infections in North and South America

Gatifloxacin (formerly AM-115) is a new 8-methoxy fluoroquinolone with an expanded spectrum against Gram-positive cocci and some anaerobes. To assess this new agent's activity, a collection of 1,676 Gram-positive cocci were selected for resistance to ciprofloxacin (> or = 4 micrograms/mL) and tested against gatifloxacin and 18 other compounds by reference broth microdilution methods. The strains (approximately 23,000 total isolates from the SENTRY Antimicrobial Surveillance Program) were from significant blood stream, respiratory tract, wound, and urinary tract infections in patients in North (38 hospitals) and South (10 hospitals) America. Against Enterococcus faecalis and E. faecium, gatifloxacin inhibited only 16% and 10% of strains compared with 12% and 5% for recently released trovafloxacin, respectively. Among Staphylococcus aureus (90% oxacillin-resistant) strains, gatifloxacin was more active (67% susceptible at < or = 4 micrograms/mL) than trovafloxacin (59%) or sparfloxacin (4%). Gatifloxacin had a wider spectrum than trovafloxacin against coagulase-negative staphylococci especially S. epidermidis, 2% versus 58% resistance. The glycopeptides, chloramphenicol and rifampin were most active. Against all genus/species groups with more than 100 sample strains (1,566), high-level resistance to gatifloxacin and trovafloxacin (> 4 micrograms/mL) was not significantly different (41.7% versus 39.1%; p > 0.05). Emerging resistance to the fluoroquinolones remains a clinical problem among Gram-positive species, and gatifloxacin seems to be active in vitro against many of these contemporary strains isolated in the Americas.

Microsurgical treatment of arteriovenous malformations: analysis and comparison with stereotactic radiosurgery

OBJECT

To compare microsurgical and stereotactic radiosurgical treatment of arteriovenous malformations (AVMs), the authors analyzed a prospective series of 72 consecutive patients who were treated microsurgically for cerebral AVMs by one neurosurgeon. The authors then compared the results of microsurgical treatment with published results of stereotactic radiosurgical treatment of small AVMs.

METHODS

Patients were categorized by age, gender, presentation, and preoperative neurological status. The AVMs were categorized by size, location, presence of deep venous drainage, and Spetzler-Martin grade. Outcome was assessed for angiographic obliteration, hemorrhage following treatment, presence of a new, persistent postoperative neurological deficit, and Glasgow Outcome Scale (GOS) score. Ordinal logistic regression was used to model the GOS score and to predict new postoperative deficits. Generalized estimating equations were used to compare published results of microsurgical and stereotactic radiosurgical treatment of AVMs. Kaplan-Meier event-free survival plots were generated to compare the two modalities with respect to hemorrhage following treatment. Overall, six patients (8.3%) exhibited a new persistent neurological deficit postoperatively. Sixty-five patients (90.3%) had a GOS score of 5. Three patients were moderately disabled and four patients were severely disabled. No patient was observed to be in a vegetative state and there were no treatment-related deaths. Seventy-one patients (98.6%) underwent intra- or postoperative angiography. Total excision of the AVM was angiographically confirmed in 70 patients (98.6% of those who underwent angiography). To date no patient has suffered from hemorrhage since the microsurgical treatment. When analysis was confined to patients whose AVMs were smaller than 3 cm in maximum diameter, the authors found a 100% angiographic obliteration rate, no new postoperative neurological deficit, and a good recovery in all patients. An analysis of all patients with Spetzler-Martin Grades I to III resulted in a 100% rate of angiographic obliteration, one patient with a new postoperative neurological deficit, and good recovery in 93% of the patients. Size of the AVM, preoperative neurological status, and patient age are associated with GOS score (for all, p < 0.02). The Spetzler-Martin grading system as well as each component of this system are associated with the development of a new postoperative neurological deficit (for all, p < 0.01). For the entire series there were fewer postoperative hemorrhages and deaths than those mentioned in published series of small AVMs treated with stereotactic radiosurgery. When these patients and published series of patients with microsurgically treated AVMs classified as Grade I to III were compared with similar patients treated radiosurgically there were significantly fewer postoperative hemorrhages (odds ratio = 0.210, p = 0.001), fewer deaths (odds ratio = 0.659, p = 0.019), fewer new posttreatment neurological deficits (odds ratio = 0.464, p = 0.013), and a higher incidence of obliteration (odds ratio = 28.2, p = 0.001) for the microsurgical group. Lifetable analysis confirms the statistically significant difference in hemorrhage-free survival time between the two groups (p = 0.002).

CONCLUSIONS

Based on this analysis, microsurgical treatment of Grades I to III AVMs is superior to stereotactic radiosurgery.

A comparison of neonatal outcomes of age-matched, growth-restricted twins and growth-restricted singletons

A retrospective cohort study was performed to determine whether growth-restricted fetuses of a twin gestation are at increased risk of adverse neonatal outcome compared with growth-restricted singletons. One cohort was comprised of 48 growth-discordant twin pregnancies in which the birth weight of the smaller twin was less than the tenth percentile. The neonatal outcomes of the 48 growth-restricted twin infants were compared with a cohort of 96 singleton infants matched by gestational age, degree of growth restriction, and gender. Outcomes evaluated included: length of stay, days of assisted ventilation, and diagnoses of morbidities of prematurity, congenital abnormalities, and neonatal death. No significant difference was detected in rates of neonatal morbidity or mortality. The overall neonatal death rate in the twins was 125 of 1000 and in the singletons was 104 of 1000 (Odds ratio 1.2, 95% confidence interval [CI]0.4-3.3). Growth-restricted twins have similar rates of adverse neonatal outcomes as compared with growth-restricted singletons. Both have high rates of morbidity and neonatal death. Twins and singletons should receive comparable diagnostic evaluation and antepartum management for growth restriction.

Ultrasound predictors of neonatal outcome in intrauterine growth restriction

Our purpose was to assess the value of commonly performed ultrasound parameters in predicting neonatal outcome of fetuses with intrauterine growth restriction (IUGR). One hundred twenty-seven patients were identified on ultrasound examination to have IUGR. Estimated weight percentile, amniotic fluid volume, umbilical artery Doppler velocimetry, and head circumference/abdominal circumference ratio were compared with neonatal outcome. Thirty infants had severely adverse courses. The degree of growth restriction was strongly associated with adverse outcome and neonatal death. Umbilical artery Doppler waveforms with absent or reverse end-diastolic flow were predicted of neonatal death, bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC), and adverse outcome in general. Oligohydramnios was predictive of adverse outcome and neonatal death. Logistic regression also showed that absent or reverse end-diastolic flow and oligohydramnios were independent predictors of adverse outcome. Ultrasound findings of low estimated weight percentile, absent or reverse end-diastolic umbilical blood flow, and oligohydramnios are independent predictors of adverse neonatal outcome of growth restricted fetuses.

Heterogeneity of hip fracture: age, race, sex, and geographic patterns of femoral neck and trochanteric fractures among the US elderly

To explore potential etiologic differences in the two major types of hip fracture, the authors computed the incidence rates of fractures of the femoral neck and trochanteric region of the proximal femur using a 5 percent sample of the US Medicare population aged 65-99 years. For the period they examined, July 1, 1986, through June 30, 1990, the rates of both hip fracture types increased with age in all race and sex categories. The proportion of hip fractures that occurred in the trochanteric region rose steeply with age among white women, but not among black women, white men, or black men. Within the United States, a north-to-south gradient in rates of both fracture types was observed among women, while no clear pattern was found for men. These findings raise the possibility of etiologic differences in the two fracture types, and the results provide further evidence of sex and racial differences in the risk of osteoporotic fractures.

Choosing covariates in the analysis of clinical trials

Much of the literature on clinical trials emphasizes the importance of adjusting the results for any covariates (baseline variables) for which randomization fails to produce nearly exact balance, but the literature is very nearly devoid of recipes for assessing the consequences of such adjustments. Several years ago, Paul Canner presented an approximate expression for the effect of a covariate adjustment, and he considered its use in the selection of covariates. With the aid of Canner's equation, using both formal analysis and simulation, the impact of covariate adjustment is further explored. Unless tight control over the analysis plans is established in advance, covariate adjustment can lead to seriously misleading inferences. Illustrations from the clinical trials literature are provided.