Impact of a fluoroquinolone restriction policy in an elderly population

BACKGROUND

In light of growing concerns of bacterial resistance to fluoroquinolones, the province of Ontario instituted a fluoroquinolone restriction policy in March of 2001. The objective of this study was to examine the immediate impact of this policy on the rates of antibiotic prescription use and infectious disease-related hospitalizations among elderly individuals who are dispensed antibiotics.

METHODS

An interrupted time series analysis was conducted from January 1, 1994, to March 31, 2002, using administrative health care databases covering more than 1.4 million residents of Ontario, Canada, aged 65 years and older. Population rates of antibiotic use and infectious disease-related hospitalizations within 4 weeks after an antibiotic prescription were examined using interventional autoregressive integrated moving average models.

RESULTS

Immediately after the introduction of the fluoroquinolone policy, fluoroquinolone prescription rates decreased to approximately 70% of expected rates (P<.01). Approximately 30% higher than expected use of sulfonamide (P=.01) and urinary anti-infectives (primarily nitrofurantoin and trimethoprim; P<.01) were observed within 1 year after policy implementation. No significant changes in the use of any other groups of antibiotics were observed. Although no significant changes in the rates of overall infection-related hospital admissions among antibiotic users were observed, the rate of hospital admission for gastrointestinal infections was 32% lower than expected in the 1 year after the policy change (P<.01). The hospital admission rate for urinary tract infections was approximately 8% higher than expected (P<.01).

CONCLUSIONS

These findings suggest that formulary restrictions to fluoroquinolones can be implemented effectively to decrease use among an elderly population without adverse impact on hospital admission rates.

Lateral bending biomechanical analysis of neck protection devices used in football

The objective of this study was to perform a dynamic biomechanical analysis of football neck collars in order to determine their effect on head and neck loading. A total of 48 tests were performed comparing the Cowboy Collar, Bullock Collar, and the Kerr Collar. A control and each collar was tested at two speeds (5 m/s and 7 m/s), three impact locations (front, top, and side of the helmet), and two shoulder pad positions (normal and raised). This paper specifically analyzes the load limiting capabilities of these collars during an impact to the side of the helmet. A 50 percentile male Hybrid III dummy was equipped with a helmet, shoulder pads, and the various neck collars mentioned. The dummy was instrumented with tri-axial accelerometers at the CG of the head. Angular rate sensors were used in the head and chest. In addition, both the upper and lower neck were instrumented with load cells. The helmet was struck with a pneumatic linear impactor to provoke rotation of the head and neck. With the side impact location, the Kerr Collar substantially reduced lower neck moment. These reductions in loads correlate with the degree to which each collar restricted the motion of the head and neck.

Analysis of linear head accelerations from collegiate football impacts

Sports-related concussions result in 300,000 brain injuries in the United States each year. We conducted a study utilizing an in-helmet system that measures and records linear head accelerations to analyze head impacts in collegiate football. The Head Impact Telemetry (HIT) System is an in-helmet system with six spring-mounted accelerometers and an antenna that transmits data via radio frequency to a sideline receiver and laptop computer system. A total of 11,604 head impacts were recorded from the Virginia Tech football team throughout the 2003 and 2004 football seasons during 22 games and 62 practices from a total of 52 players. Although the incidence of injury data are limited, this study presents an extremely large data set from human head impacts that provides valuable insight into the lower limits of head acceleration that cause mild traumatic brain injuries.

Head acceleration is less than 10 percent of helmet acceleration in football impacts

Sports-related concussions constitute 20 percent of brain injuries each year in the United States. Concussion research has included a variety of instrumentation and techniques to measure head accelerations. Most recently, the Head Impact Telemetry (HIT) System (Simbex, Lebanon, NH), a wireless system that provides real-time data from impacts, is used to measure in-situ head accelerations in collegiate football. The purpose of this study is to compare helmet shell acceleration to head center of gravity acceleration using two measures of linear head acceleration. A study of 50 helmet to helmet impact tests using a pendulum provided a range of head accelerations from 5 g to 50 g. The primary measure of head acceleration is accelerometers mounted at the center of gravity of the Hybrid III head. A secondary measure is the in-helmet HIT System. The series of 50 pendulum impacts included three impact velocities of 2.0 m/s, 3.5 m/s and 5.0 m/s at four different impact locations. The impact locations were on the side, back, top and just above the facemask on the front. By comparing these two measured head accelerations and the helmet acceleration during a pendulum impact, it is shown that the response of the head and the helmet vary greatly and the in-helmet system matches the head and not helmet acceleration. Specifically, head acceleration is less than 10 percent of helmet acceleration in football impacts; moreover, the HIT System is able to accurately measure the head acceleration.

Recombinant adeno-associated virus-mediated correction of lysosomal storage within the central nervous system of the adult mucopolysaccharidosis type VII mouse

The central nervous system (CNS) is a predominant site of involvement in several lysosomal storage diseases (LSDs); and for many patients, these diseases are diagnosed only after the onset of symptoms related to the progressive accumulation of macromolecules within lysosomes. The mucopolysaccharidosis type VII (MPS VII) mice are deficient for the lysosomal enzyme beta-glucuronidase and, by early adulthood, develop a significant degree of glycosaminoglycan storage within neuronal, glial, and leptomeningeal cells. Using this animal model, we investigated whether gene transfer mediated by a recombinant adeno-associated virus (rAAV) vector is capable of reversing the progression of storage lesions within the CNS. Adult MPS VII mice received intracerebral injections of 4 X 10(7) infectious units of a rAAV vector carrying the murine beta-glucuronidase (gus-s(a)) cDNA under the transcriptional direction of the cytomegalovirus immediate-early promoter and enhancer. By 1 month after vector administration, transgene-derived beta-glucuronidase was present surrounding the injection site. Enzyme levels were between 50 and 240% of that found in wild-type mice. This level of beta-glucuronidase activity was sufficient to reduce the degree of lysosomal storage. Moreover, the reduction in storage was maintained for at least 3 months post-rAAV administration. These data demonstrate that rAAV vectors can transduce the diseased CNS of MPS VII mice and mediate levels of transgene expression necessary for a therapeutic response. Thus, rAAV vectors are potential tools in the treatment of the mucopolysaccharidoses and other lysosomal storage diseases.

Gene transfer to the intestinal tract: a new approach using selective injection of the superior mesenteric artery

Gene transfer to the intestinal tract has many potential applications, including complementation of single gene disorders, genetic immunization, and ectopic production of therapeutic molecules. Because the intralumenal approach to vector administration has not been highly successful, we tested whether the circulation can be used as a route to transfer genes to intestinal cells. The superior mesenteric artery (SMA) and vein (SMV) of adult Lewis rats were isolated and an adenoviral vector expressing the Escherichia coli LacZ gene was injected into the SMA. In one set of experiments, both vessels remained patent throughout the entire procedure. In a second group of animals, both vessels were occluded by clamping the SMA 1 cm distal to the injection site and the SMV proximal to the portal vein. In the absence of vascular clamps, gene transfer was evident throughout the small bowel, localized near the serosal surface within the muscularis propria. Occlusion of the SMA and SMV limited gene delivery to a short segment of bowel and shifted beta-galactosidase activity toward the mucosal surface. At the level of microscopy, most of the transduction events were in the lamina propria; transduced mucosal epithelial cells were occasionally observed. These data demonstrate that intestinal gene transfer can be accomplished through the circulation, and that targeting specific regions is feasible.

CT of pseudomembranous colitis

A case is presented in which computed tomography of the abdomen was performed to search for possible peritoneal abscess. The incidental observation of an irregularly thickened wall of the colon led to the diagnosis of pseudomembranous colitis.