Trends in CT scan rates in children and pregnant women: teaching,private, public and nonprofit facilities

Background

Radiation exposure from medical sources now equals or exceeds that from natural background sources, largely attributable to a 20-fold increase in CT use since 1980. Increasing exposure to children and fetuses is of most concern due to their heightened susceptibility. More recently, CT use may be leveling or decreasing, but it is unclear whether this change is widespread or varies by type of institution.

Objective

We sought to characterize trends in CT utilization in California hospitals and emergency departments among children and pregnant women, looking at different types of facilities, such as teaching, private, public and nonprofit institutions.

Materials and methods

We examined frequency of CT examinations by year from 229 facilities reporting CT usage in routinely collected California statewide data for 2005–2012. We modeled trends overall and by facility type.

Results

CT scans for pediatric and pregnant patient visits in the emergency department increased initially, then started to decline after 2008. Among hospital admissions, rates declined or leveled after 2005. In the emergency department, CT rates varied between types of facilities, with teaching hospitals reducing use sooner and more sharply than other types of facilities.

Conclusion

CT utilization in California among children and pregnant women has begun to level or decline. Still, population exposure remains at historically high levels, warranting consideration of potential public health implications. Further examination of reasons for trends among hospital types, particularly how teaching hospitals have reduced rates of CT utilization, may help identify strategies for CT reduction without compromising patient care.     

Purine Nucleoside Phosphorylase Deficiency: EVIDENCE FOR MOLECULAR HETEROGENEITY IN TWO FAMILIES WITH ENZYME-DEFICIENT MEMBERS

Purine-nucleoside phosphorylase (NP) deficiency is associated with severely defective thymus-derived (T)-cell and normally functioning bone marrow-derived (B)-cell immunity. In this study, two unrelated families with a total of three NP deficient members were investigated.High pressure liquid chromatography of the plasma of the three patients showed inosine levels greater than 66 muM. This nucleoside was absent from the plasma of their parents and control samples.NP was purified from normal human erythrocytes by affinity chromatography and an antiserum prepared in rabbits was used to study the NP variants in the two families.In family M the patient had no detectable erythrocyte NP activity and no detectable immunological-reacting material (irm) to the NP antibody. The parents, who are second cousins, had less than one-half of normal enzyme activity and approximately 14% irm attributable to a variant protein. Their electrophoretic patterns revealed a series of isozymes with slower than normal migration.In family B the patients had 0.5% residual enzyme activity and about one-half normal irm. Their electrophoretic pattern showed faintly staining bands which migrated faster than normal NP. The mother of the patients had one-half normal enzyme activity, 11% irm attributable to her variant protein, and a normal electrophoretic pattern. The father had less than one-half normal enzyme activity, equal amounts of normal and variant irm, and an electrophoretic pattern that showed increased activity of the more rapidly migrating isozyme bands.The combined use of immunological and electrophoretic techniques has shown the presence of three separate mutations; one in family M and two in family B associated with severely defective T-cell function.     

Small Airways in Idiopathic Pulmonary Fibrosis: COMPARISON OF MORPHOLOGIC AND PHYSIOLOGIC OBSERVATIONS

18 patients with idiopathic pulmonary fibrosis were studied to determine if they had morphologic evidence of small airways disease and if physiologic testing could predict morphologic findings. In the presence of normal airway function by standard physiologic studies (forced expiratory volume in 1 s/forced vital capacity and airway resistance by plethysmography), dynamic compliance, maximum expiratory flow-volume curves, and maximum flowstatic recoil curves were measured to detect physiologic alterations consistent with small airways abnormalities. These physiologic data were then compared with estimates of small airways diameter made in lung biopsy specimens.     

Antifungal Activity of 3′-Deoxyadenosine (Cordycepin)

The antifungal activity of the nucleoside analog 3′-deoxyadenosine (cordycepin) was studied in a murine model of invasive candidiasis. When protected from deamination by either deoxycoformycin or coformycin, both of which are adenosine deaminase inhibitors, cordycepin exhibited potent antifungal efficacy, as demonstrated by prolongation of survival and a decrease in CFU in the kidneys of mice treated with cordycepin plus an adenosine deaminase inhibitor. The antifungal effect was seen with three different Candida isolates: Candida albicans 64, a relatively fluconazole-resistant clinical isolate of C. albicans (MIC, 16 μg/ml), and the fluconazole-resistant Candida krusei. Cordycepin and related compounds may provide another avenue for the discovery of clinically useful antifungal drugs.     

Influence of patient age on the susceptibility patterns of Streptococcus pneumoniae isolates in North America (2000-2001): report from the SENTRY Antimicrobial Surveillance Program

Risks of developing resistance in Streptococcus pneumoniae can be greatly influenced by antimicrobial use that is often dictated by patterns of prescribing at various patient ages. The results from the SENTRY Antimicrobial Surveillance Program (2000-2001; North America) were examined for differing susceptibility profiles (25 antimicrobials) indexed by five patient age groups. All MIC results were from reference methods performed in central laboratories. Pneumococcal resistance rates in the youngest patient group (0-5 years) were significantly (p < 0.05) higher for penicillin, other beta-lactams, macrolides, tetracyclines and trimethoprim/sulfamethoxazole. In contrast, fluoroquinolone resistance in S. pneumoniae was greatest in the patients >/= 65 years (1.4% resistance to gatifloxacin, levofloxacin and moxifloxacin), where use of this class has been escalating. Continued local and global surveillance of resistances in common respiratory tract pathogens such as S. pneumoniae appears to be prudent practice to guide effective chemotherapy.     

Oxazolidinone susceptibility patterns in 2004: report from the Zyvox Annual Appraisal of Potency and Spectrum (ZAAPS) Program assessing isolates from 16 nations

OBJECTIVES: To investigate the activity of linezolid (an oxazolidinone), a potent choice for community- and hospital-acquired infections, via a worldwide surveillance network called the Zyvox Annual Appraisal of Potency and Spectrum (ZAAPS) Program. METHODS: A total of 4098 Gram-positive strains were collected from 42 laboratories located in North America (five sites in Canada), South America (10 sites), Europe (16 sites) and the Far East (11 sites). Each country or site submitted 200 isolates (Canada submitted 200 isolates for each of five sites; total 1000) for confirmation of organism identification and reference MIC processing. Nearly 25 comparator agents were tested along with quality control strains, and interpretative criteria from the CLSI, formerly the NCCLS, M100-S15 were applied. No linezolid resistance was detected in strains from 16 monitored countries in 2004. RESULTS: Linezolid remained highly active against Streptococcus pneumoniae, viridans group and beta-haemolytic streptococci (MIC90, 1 mg/L). Against Staphylococcus aureus, linezolid showed 99.5% of results at 0.5-2 mg/L with only one isolate at 4 mg/L. Oxacillin-resistant S. aureus rates varied between nations and ranged from 1.4% in Sweden to 29.5% in the UK to 65.2% in Mexico. Linezolid MIC values were generally one log2 dilution step lower for coagulase-negative staphylococci (CoNS) when compared with S. aureus. No CoNS strains produced a linezolid result at 4 mg/L. Compared with ZAAPS 2002 and 2003 results for enterococci where seven resistant strains were identified, the 2004 data revealed no resistance and 98.1% of linezolid MIC results were at 1 or 2 mg/L. Vancomycin-resistant enterococci (5.3% overall) varied markedly by country including a high of 47.2% in Korea. CONCLUSIONS: Linezolid continues to be effective in vitro against Gram-positive pathogens from five continents and no oxazolidinone-resistant strains were identified among the 4098 systemically collected strains (2004) or among 20 158 non-United States isolates for the entire ZAAPS Program (2002-04).     

Inhibition of Mycoplasma pneumoniae by Actinomycin D

Growth of Mycoplasma pneumoniae was completely prevented by 0.06 mug of actinomycin D/ml, and 0.00375 mug/ml caused 90% inhibition. It thus appears that M. pneumoniae is more susceptible to actinomycin D than previously reported. Low concentrations (0.019 mug/ml) of the antibiotic primarily inhibited ribonucleic acid synthesis and high concentrations (20 mug/ml) inhibited both ribonucleic and deoxyribonucleic acid synthesis.     

Effects of Prostaglandin Cyclic Endoperoxides on the Lung Circulation of Unanesthetized Sheep

Although prostaglandins E₂ and F_2α have been suggested as mediators of the pulmonary hypertension seen after endotoxin infusion or during alveolar hypoxia, their precursors, the endoperoxides (prostaglandins G₂ and H₂) are much more potent vasoconstrictors in vitro. In this study we compared the effects of prostaglandin (PG)H₂, a stable 9-methylene ether analogue of PGH₂ (PGH₂-A), PGE₂, and PGF_2α on pulmonary hemodynamics in awake sheep. The animals were prepared to allow for measurement of (a) lung lymph flow; (b) plasma and lymph protein concentration; (c) systemic and pulmonary vascular pressures; and (d) cardiac output. We also determined the effect of prolonged PGH₂-A infusions on lung fluid balance and vascular permeability by indicator dilution methods, and by assessing the response of lung lymph. Both PGH₂ and PGH₂-A caused a dose-related increase in pulmonary artery pressure: 0.25 μg/kg × min tripled pulmonary vascular resistance without substantially affecting systemic pressures. Both were 100 times more potent than PGE₂ or PGF_2α in this preparation. PGH₂-A, as our analysis of lung lymph and indicator dilution measurements show, does not increase the permeability of exchanging vessels in the lung to fluid and protein. It does, however, augment lung fluid transport by increasing hydrostatic pressure in the pulmonary circulation. We conclude: (a) that PGH₂ is likely to be an important mediator of pulmonary vasoconstriction; (b) its effects are probably not a result of its metabolites PGE₂ or PGF_2α.