Utilization of screening mammography: comparison of different physician specialties

Data obtained on 426 consecutive patients referred to a breast center by 122 physicians, including family practitioners, general surgeons, and other specialists, showed that the obstetricians-gynecologists referred the greatest average number of patients per physician, with more than 50% of these referrals for screening mammography. Internists referred fewer patients by nearly a factor of ten, with only one-third of these patients referred for screening mammography. Internists may be the weakest link in the utilization of screening mammography.     

Blood group A immunodeterminants on human red cells differ in biologic activity and sensitivity to alpha-N-acetylgalactosaminidase

BACKGROUND: Epitopes of blood group A antigen can be enzymatically cleaved from red cells (RBCs), but the extent of cleavage required for normal survival in allogeneic blood transfusion recipients is unknown. Therefore, the cleavage rates were studied for A antigen epitope binding of 1) complement-activating anti-A, 2) Dolichos biflorus anti- A, lectin, and 3) hemagglutinating anti-A during incubation with a purified alpha-N-acetylgalactosaminidase, E.C. 3.2.1.49 (alpha- GalNAc'ase). STUDY DESIGN AND METHODS: Suspensions of group A RBCs were incubated with alpha-GalNAc'ase. Cells were removed at intervals, washed, and tested for loss of binding by monoclonal, polyclonal, and complement-activating anti-A, D. biflorus anti-A1 lectin, and Ulex europaeus anti-H lectin. RESULTS: A epitopes binding D. biflorus lectin were highly susceptible to alpha-GalNAc'ase; simultaneously with their loss, binding with U. europaeus lectin emerged. Loss of complement- mediated hemolysis was slower. A epitopes binding hemagglutinating anti- A were most resistant. Cleavage of A epitopes from membrane glycosphingolipids with short oligosaccharide chains was similarly resistant. Rates of cleavage from A1 and A2 RBCs were similar. CONCLUSION: RBC epitopes of blood group A differ in susceptibility to cleavage and biologic reactivity, which suggests that subsets mediating important biologic functions exist on functionally and topographically distinct membrane glycoconjugates.     

Triceps denervation as a predictor of elbow flexion contractures in C5 and C6 tetraplegia

OBJECTIVE: To determine whether the existence of elbow flexion contractures in persons with C5 or C6 tetraplegia is related to a lack of residual voluntary triceps function and triceps denervation (ie, lower motoneuron damage). DESIGN: A retrospective study of impairment data from 74 arms to identify the incidence of elbow flexion contractures and the contributing factors toward this deformity. SETTING: Five spinal cord injury (SCI) rehabilitation centers in the United States, 1 in England, and 1 in Australia. PARTICIPANTS: Forty-three subjects with motor complete C5 or C6 traumatic SCI. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Active and passive elbow extension, triceps voluntary muscle strength, and triceps response to electric stimulation. RESULTS: Subjects with weak voluntary triceps had significantly fewer and less severe elbow flexion contractures than those with paralyzed triceps ( P =.024). Subjects with completely denervated triceps (ie, no response to electric stimulation) had significantly more elbow flexion contractures than subjects with even a weak response to electric stimulation ( P =.003). Overall, 51% of the arms could not be passively extended to zero. Forty-six percent of the arms classified as C5 lacked full passive elbow extension, compared with 63% of the arms classified as C6 ( P =.302). CONCLUSIONS: A relationship has been found between elbow flexion contractures and lack of residual voluntary triceps and triceps denervation in subjects with C5 or C6 tetraplegia. There should be a greater awareness of the elbow flexion contractures that may develop as a result of this relationship. A better understanding of this deformity and its characteristics can lead to more effective clinical treatment and prevention strategies.     

Applying psychometric criteria to functional assessment in medical rehabilitation: I. Exploring unidimensionality

While rehabilitation providers are facing increasing pressure to document treatment outcomes, critics have warned against the inappropriate use of ordinal functional assessment data in arithmetic operations. Two salient criticisms concern the combination of items representing multidimensional abilities into a single total score, and the indeterminate distances between hierarchical functional assessment scale categories. In this initial study, the factor structure of the Patient Evaluation and Conference System (PECS) was studied to assess the potential for unidimensional measurement. Factor analysis of a multidiagnostic dataset (n = 3,564) yielded eight factors accounting for 60% of the variance among 68 PECS items. The factors indicate that several unidimensional measures may underlie the PECS. These factors are delineated, and further studies of unidimensionality and additivity are recommended.     

Analysis of serious non‐AIDS events among HIV‐infected adults at Latin American sites

Objective

Acquired immune deficiency appears to be associated with serious non‐AIDS (SNA)‐defining conditions such as cardiovascular disease, liver and renal insufficiency and non‐AIDS‐related malignancies. We analysed the incidence of, and factors associated with, several SNA events in the LATINA retrospective cohort.

Materials and methods

Cases of SNA events were recorded among cohort patients. Three controls were selected for each case from cohort members at risk. Conditional logistic models were fitted to estimate the effect of traditional risk factors as well as HIV‐associated factors on non‐AIDS‐defining conditions.

Results

Among 6007 patients in follow‐up, 130 had an SNA event (0.86 events/100 person‐years of follow‐up) and were defined as cases (40 with cardiovascular events, 54 with serious liver failure, 35 with non‐AIDS‐defining malignancies and two with renal insufficiency). Risk factors such as diabetes, hepatitis B and C virus coinfections and alcohol abuse showed an association with events, as expected. The last recorded CD4 T‐cell count prior to index date (P=0.0056, with an average difference of more than 100 cells/μL) and area under the CD4 cell curve in the year previous to index date (P=0.0081) were significantly lower in cases than in controls. CD4 cell count at index date was significantly associated with the outcome after adjusting for risk factors.

Conclusions

The incidence and type of SNA events found in this Latin American cohort are similar to those reported in other regions. We found a significant association between immune deficiency and the risk of SNA events, even in patients under antiretroviral treatment.     

Conduction block of whole nerve without onset firing using combined high frequency and direct current

This study investigates a novel technique for blocking a nerve using a combination of direct and high frequency alternating currents (HFAC). HFAC can produce a fast acting and reversible conduction block, but cause intense firing at the onset of current delivery. We hypothesized that a direct current (DC) block could be used for a very brief period in combination with HFAC to block the onset firing, and thus establish a nerve conduction block which does not transmit onset response firing to an end organ. Experiments were performed in rats to evaluate (1) nerve response to anodic and cathodic DC of various amplitudes, (2) degree of nerve activation to ramped DC, (3) a method of blocking onset firing generated by high frequency block with DC, and (4) prolonged non-electrical conduction failure caused by DC delivery. The results showed that cathodic currents produced complete block of the sciatic nerve with a mean block threshold amplitude of 1.73 mA. Ramped DC waveforms allowed for conduction block without nerve activation; however, down ramps were more reliable than up ramps. The degree of nerve activity was found to have a non-monotonic relationship with up ramp time. Block of the onset response resulting from 40 kHz current using DC was achieved in each of the six animals in which it was attempted; however, DC was found to produce a prolonged conduction failure that likely resulted from nerve damage.     

The geographic availability and associated utilization of dual-energy X-ray absorptiometry (DXA) testing among older persons in the United States

Summary  Using national Medicare data from 1999–2006, we evaluated the relationship between travel distance and receipt of dual-energy X-ray absorptiometry (DXA). After adjusting for potentially confounding factors, travel distance was strongly associated with DXA testing. Rural residents were most strongly dependent on the availability of DXAs performed in physician offices. Introduction  Medicare reimbursement for DXAs performed in non-facility settings (e.g., physician offices) decreased in 2007. With declining reimbursement, some DXA providers may cease providing this service, which would increase travel distance for some people. The impact of travel distance on access to DXA is unclear. Methods  Using national Medicare data, we identified claims for DXA to evaluate trends in the number and locations of DXAs performed. Travel distance was the distance from beneficiaries’ residence and the nearest DXA provider. Binomial regression evaluated the relationship between travel distance and receipt of DXA. Results  In 2006, 2.9 million DXAs were performed, a 103% increase since 1999. In 2005–2006, 8.0% of persons were tested at non-facility sites versus 4.2% at facility sites. The remainder (88%) had no DXA. Persons traveling 5–9, 10–24, 25–39, and 40–54, and ≥55 miles were less likely to receive DXA (adjusted risk ratios = 0.92, 0.79, 0.43, 0.32, and 0.26, respectively, <5 miles referent). Rural residents were more dependent than urban residents on the availability of DXA from non-facility providers. Conclusion  Approximately two-thirds of DXAs in 2005–2006 were performed in non-facility settings (e.g., physician offices). Rural residents would have preferentially reduced access to DXA if there were fewer non-facility sites.     

Incidence and burden of rotavirus gastroenteritis in Japan, as estimated from a prospective sentinel hospital study

We assessed the burden of rotavirus infection-related disease, in terms of hospitalization and associated costs, at 3 sentinel hospitals in Akita prefecture, Japan. From January 2001 through December 2002, a total of 443 children <5 years of age were hospitalized for acute gastroenteritis. Of 422 stool specimens collected, 244 (58%) tested positive for rotavirus. Only 7.8% of the rotavirus disease-associated hospitalizations involved infants <6 months of age, whereas most cases of disease (39%) were reported in the second year of life, and 89% of cases had occurred by 36 months of age. The mean severity score for rotavirus gastroenteritis resulting in hospitalization was 16.5, according to the modified 20-point severity scoring system. The average associated direct medical cost was 136,000 yen (1236 US dollars) per case and was similar among the 3 hospitals. The estimated incidence of rotavirus disease-associated hospitalizations among children <5 years of age was 7.9-17.6 hospitalizations/1000 person-years, and the estimated cumulative incidence by 5 years of age was 6.6%. Thus, approximately 1 in 15 children will require hospitalization due to rotavirus diarrhea by their fifth year of life. In Japan, this would mean that 78,000 children <5 years of age would be hospitalized each year, resulting in a direct medical cost of 10 billion yen (96 US dollars million). The burden associated with rotavirus gastroenteritis in Japan is substantial and might be reduced through the introduction of vaccines.