Analysis of interrupted time series mortality trends: an example to evaluate regionalized perinatal care.

Interrupted time series designs are frequently employed to evaluate program impact. Analysis strategies to determine if shifts have occurred are not well known. The case where statistical fluctuations (errors) may be assumed independent is considered, and a segmented regression methodology presented. The method discussed ia applied to the assessment of changes in local and state perinatal postneonatal mortality to identify historical trends and will be used to evaluate the impact of the North Carolina Regionalized Perinatal Care Program when seven years of post-program mortality data become available. The perinatal program region is contrasted with a control region to provide a basis for interpretation of differences noted. Relevant segmented regression models provided good fits to the data and highlighted mortality trends over the last 30 years. Considerable racial differences in these trends were identified, particularly for postneonatal mortality. Segmented regression is considered relevant for the analysis of interrupted time series designs in other applications when errors can be taken to be independent. Thus, the methodology may be regarded as a general statistical tool for evaluation purposes.     

Survey approach to estimating demand for physician assistants

A national probability sample of physicians was surveyed by mail to provide an estimate of the number of job openings for physician assistants (PAs). The responses were used to undertake an empirical analysis of the factors which influence a physician's decision to hire a PA. Estimates were adjusted to account for survey non-response. This approach may be useful for estimating the employment demand for other types of health workers employed by physicians.It was found that in 1976 there was an unconditional demand for 20.338 PAs and a further conditional demand for 3417 PAs. This contrasts sharply with the fact that as of March 1977 only 4845 PAs had graduated from training programs. Approximately 53% of this employment demand was from physicians in the primary care specialties (general/family practice, obstetrics/gynecology, internal medicine, and pediatrics). Of note was the finding that physicians expected to pay PAs a lower salary than was being received in the market place. Further, 27% of physicians not willing to hire PAs indicated lack of knowledge about them as the main reason for not hiring.     

氯化钐、氯化镨对大鼠肝脏形态及LPO、SOD活性的影响

本实验采用不同途径给予断乳Ｗｉｓｔａｒ大鼠小剂量（０．０５ｍｇ／ｋｇ、０．０２５ｍｇ／ｋｇ）氯化角钐（ＳｍＣｌ３）、氯化镨（ＰｒＣｌ３）后，测定了肝脏中过氧化脂质（ＬＰＯ）和超氧化物歧化酶（ＳＯＤ）的含量，观察了肝脏的超微结构。结果表明：ＳｍＣｌ３和ＰｒＣｌ３均使肝脏中ＬＰＯ活性降低、ＳＯＤ活性升高，二者比较ＰｒＣｌ３的作用更为明显，肝脏未见明显形态学改变。     

The use of closed circuit television in the teaching of dental technology

A bstract — A low cost, single-operator, four-camera, closed-circuit television system was developed to teach dental technology to large classes (120) of second and third year (preclinical) undergraduates. Its use permits demonstrations to be conducted, recorded and played back, with no electronic knowledge, little training, and a minimum of preparation and assistance. The field of view is from above the demonstration table, and is selected by pushbutton in the size range 30 cm × 20 cm down to 3 cm × 2 cm. The system has many advantages, few disadvantages, is reliable in operation, and is acceptable to students.     

An empiric study of ecological inference.

Aggregate-level (macro) data are sometimes used when examining health care issues. Although they may be more accessible than individual (micro) observations, their interpretation is subject to ecological bias which in most cases is not measurable. This paper examines the implications of using aggregate-level data by conducting two separate analyses (micro and macro). Using as a database hospital episodes of care for the North Carolina Medicare aged population, regression models are developed from an examination of geographic grouping effects to explore the impact of extended care services, skilled nursing facility, and home health agency care on acute care hospital days. Specific problems encountered are: variable definition, collinearity , variance reduction, dilution of effect, spurious correlation, and observation influence. Stronger collinear (correlation among independent variables) relations occur at the macro-level than at the micro-level and spurious macro-correlations result from model specification and definition of interaction effects.     

The potential for increase in the periodontal diseases of the aged population

The periodontal disease trends in the nation's older adults aged 55 to 74 years are assessed using National Center for Health Statistics data spanning an approximate 12-year period. Both the 1960 to 1962 Health Examination Survey and the 1971 to 1974 Health and Nutrition Examination Survey I surveys used similar multistaged stratified probability samples. Examinations were calibrated and the collection of periodontal disease (PI), oral hygiene (OHI) and tooth loss scores were standardized. Data were collected on 1567 persons in 1960 to 1962 and 4746 persons in 1971 to 1974. The mean PI scores between the two surveys were not statistically different. However, when the periodontal diseases were divided into individuals with or without pockets, there was a significant decline in the per cent without pockets (P less than 0.001) while the per cent with pockets remained unchanged or increased. The significant reduction in OHI scores (P less than 0.02) seems to validate the decrease in gingivitis. The improvement in tooth loss was reflected by both the greater proportion of dentulous adults, and among the dentulous, a retention of more than two teeth per person by 1971 to 1974. A hypothesis is discussed regarding tooth retention and the periodontal diseases with projections for the year 2000.     

Resting-state functional connectivity abnormalities in limbic and salience networks in social anxiety disorder without comorbidity

The neurobiology of social anxiety disorder (SAD) is not yet fully understood. Structural and functional neuroimaging studies in SAD have identified abnormalities in various brain areas, particularly the amygdala and elements of the salience network. This study is the first to examine resting-state functional brain connectivity in a drug-naive sample of SAD patients without psychiatric comorbidity and healthy controls, using seed regions of interest in bilateral amygdala, in bilateral dorsal anterior cingulate cortex for the salience network, and in bilateral posterior cingulate cortex for the default mode network. Twelve drug-naive SAD patients and pair-wise matched healthy controls, all drawn from the Netherlands Study of Depression and Anxiety sample, underwent resting-state fMRI. Group differences were assessed with voxel-wise gray matter density as nuisance regressor. All results were cluster corrected for multiple comparisons (Z>2.3, p<.05). Relative to control subjects, drug-naive SAD patients demonstrated increased negative right amygdala connectivity with the left middle temporal gyrus, left supramarginal gyrus and left lateral occipital cortex. In the salience network patients showed increased positive bilateral dorsal anterior cingulate connectivity with the left precuneus and left lateral occipital cortex. Default mode network connectivity was not different between groups. These data demonstrate that drug-naive SAD patients without comorbidity show differences in functional connectivity of the amygdala, and of areas involved in self-awareness, some of which have not been implicated in SAD before.     

Identification of amino acid residues in PEPHC1 important for binding to the tumor-specific receptor EGFRvIII

EGFRvIII is a cancer-specific epidermal growth factor tyrosine kinase receptor mutation, expressed in different kinds of cancer, in particular ovarian, glioblastomas, and breast cancer. A peptide, PEPHC1, has previously been shown to bind selectively to EGFRvIII. An alanine scan was performed to identify the amino acid residues important for binding of PEPHC1 to EGFRvIII. The results indicate that the amino acid residues at the N-terminus of PEPHC1 are essential for the binding to the mutated receptor. One analog, [Ala(12)]PEPHC1, showed higher selective binding to EGFRvIII than PEPHC1. On the basis of these results, six truncated peptide analogs derived from the N-terminus of PEPHC1, H-HFIIL-NH2, H-HFIILG-NH2, H-HFIILGF-NH2, H-HFIILGFM-NH2, H-HFLIIGFMR-NH2, and H-HFLIIGFMRR-NH2 were synthesized and tested in the same manner. We observed that H-HFIIL-NH2 and H-HFIILG-NH2 showed almost threefold lower binding to the mutated receptor than PEPHC1, whereas the remainder showed 25% lower binding. The secondary structure of the PEPHC1 analogs was investigated by far UV circular dichroism spectroscopy and their binding correlated with various structural parameters such as charge, mean hydrophobicity (), and mean hydrophobic moment (). This work provides data, which will be useful in the development of novel peptide-based ligands for EGFRvIII-targeted diagnostics and therapy. This work was in part presented at the 17th International Symposium on Radiopharmaceutical Sciences, April 2007, Aachen, Germany.     

Nurse-led triage of acute medical admissions: accurate and time-efficient

In many hospitals a variety of triage systems are used by senior medical staff to identify likely length of stay (LOS) of acute medical admissions and thus facilitate a streamlined admission under either acute medicine or general internal medicine (GIM). The authors evaluated if senior nursing staff on the medical assessment unit could triage patients depending on their predicted LOS as accurately as consultant acute physicians. Each of 193 medical admissions were independently triaged by both groups to either acute medicine (<48 hours) or GIM (>48 hours) depending on predicted LOS. The accuracy of patient triage was identical for senior nursing staff and consultants (80.8% vs 81.9%), when 95% confidence intervals are taken into account. Nursing staff triaged patients a mean of 8.5 hours earlier than consultants. This study demonstrates that triage of acute medical admissions is a practical extension of the senior nursing role and has been successfully implemented, with accuracy of nursing triage (83.5%) being maintained in a repeat study 6 months later.