The prevalence and antibiotic sensitivity of oral Viridans streptococci in healthy children and children with disabilities in Kuwait

The purpose of this study was to compare the antibiotic susceptibility profiles of Viridans streptococci (VS) isolated from the oral cavity of healthy children and children with disabilities in Kuwait. Plaque samples were collected from the tooth and tongue surfaces of 102 healthy children and 102 children who were intellectually disabled and institutionalized. The resistance to seven antibiotics (amoxicillin, cephalothin, clindamycin, erythromycin, penicillin G, tetracycline, and vancomycin) was tested.
A total of 330 (44.5%) VS were isolated from the children who were healthy and 411 (55.5%) from children with disabilities. The most common isolates were S. salivarias (27.3%) in healthy children; S. sanguis (22.6%) was predominant among children who were disabled. S. mutans was found in 12.1% of the healthy children and in 16.5% of the children who were disabled. The combined percentage of resistant strains (healthy and disabled) was found to be highest with amoxicillin (43%) and lowest with vancomycin (12%). S. sanguis, S. mitis and S. oralis were more resistant in healthy children (45%, 56%, and 55% respectively) than in children with disabilities (40%, 47% and 47% respectively). S. mutans was the least resistant species to all antibiotics in both groups of children. About 56% of ali streptococci isolated from both groups were resistant to at least one of the antibiotics tested.
The data showed that there was a diference in the level of resistance of oral VS isolated from healthy children and children with disabilities to some antibiotics commonly used in dentistry.     

Use of inferior vena cava filters in the Medicare population

To examine the use of inferior vena cava (IVC) filters, we performed a population-based study using a 5% random sample of the United States Medicare population (1.25 million persons). Filter placement and its timing relative to diagnosis of venous thromboembolism (VTE) were determined using both hospital and physician Medicare billing codes after detailed review of large samples of complete individual claims records. Comorbid conditions and mortality were also noted. From July 1986 through June 1989, a total of 806 patients in the sample population received IVC filters. Mortality rates after filter placement were high: 16% during initial hospitalization, 32% within 6 months of filter placement, and 48% after 2 years. However, only 3 (1%) of 423 patients who underwent filter placement without the diagnosis of pulmonary embolism (PE) suffered PE within 1 year of filter placement. Use of IVC filters increased significantly over the study period (p <0.001).Rates of filter placement among the nine census divisions of the United States differed significantly (p<0.001).An East-West trend was notable with the highest rate (37 filters/100,000 enrollees/yr) in New England, as compared with 14 filters/100,000 enrollees/yr in the Pacific Division. No explanation for these regional-differences was evident after patient demographics and comorbidity were examined. Vena cava filters prevent PE for at least 1 year after placement. The frequency of IVC filter use in elderly patients is increasing and varies substantially by region. Although reasons for these trends are unclear, these findings suggest the need for uniform practice guidelines for IVC filter placement.Supported in part by the National Institutes of Aging, grant R0 1 AG 07-146, and by a training grant from the National Library of Medicine (NIH 5 T15 LM07044) to Dr. Birkmeyer.     

Sound-Tissue Interaction: The Physical Basis of Bone Ultrasonometry and Limitations of Existing Methods

Ultrasound measurements of bone are generally obtained using transmission rather than pulse-echo techniques because of its highly attenuating nature. Ultrasound velocity and attenuation measurements are utilized. For velocity, there are well-defined fundamental relationships describing the dependence on the elasticity and density of bone. However, the practical implementation and signal processing of velocity measurements has led to a significant variability in results from different commercial systems. We may measure either phase of group velocity, for the latter, adopting a range of pulse arrival definitions. We are offered bone velocity, heel velocity, time of flight, and amplitude-dependent velocity. For attenuation measurements, however, the reverse is true. We generally record the increase in attenuation with frequency (0.2-0.6 MHz), termed broadband ultrasound attenuation (BUA). Although first described in 1984, because of the complex interplay of attenuation mechanisms, there still lacks a fundamental understanding of the dependence of BUA on the material and structural properties of cancellous bone. With the increasing number of commercial systems available, there is an urgent need to understand the intrinsic (artefact free) and system estimation of ultrasound velocity and attenuation parameters that may be implemented to characterise bone and provide clinical information.