A discordancy test approach to identify outliers of length of hospital stay

A discordancy test approach is proposed to identify outliers of inpatient length of stay. This has implications not only for benchmarking service delivery but also for linking budget allocation procedures to efficiency of health service provisions. The effects of shifting trim point thresholds on hospital payments are assessed in a case study of a group of obstetrical patients.     

Protein balance in the first week of life in ventilated neonates receiving parenteral nutrition

BACKGROUND: Protein intake is frequently delayed in ill neonates because of concerns about their ability to metabolize substrates. OBJECTIVE: We aimed to determine the factors affecting protein balance in ventilated, parenterally fed newborns during the first week of life. DESIGN: Leucine kinetic studies were performed in 19 neonates by using the [1-(13)C]leucine tracer technique after 24 h of a stable total parenteral nutrition (TPN) regimen. TPN intakes were prescribed by rotating attending physicians, enabling assessment of protein metabolism over a range of clinically used nutrient intakes. RESULTS: Mean (+/-SD) birth weight was 1.497 +/- 0.779 kg, gestational age at birth was 30.3 +/- 4.0 wk, and age at study was 3.9 +/- 1.4 d. Amino acid intakes (AAIs) ranged from 0.0 to 2.9 g x kg(-1) x d(-1). Based on leucine kinetic data, protein balance was calculated as the difference between protein synthesis and catabolism. By multiple regression analysis, AAI was the only predictor associated independently with protein balance (P < 0.01); energy intake, lipid intake, glucose intake, birth weight, and gestational age were not. Both leucine oxidation and nonoxidative leucine disposal rates were significantly correlated with leucine intake (P < 0.0005 and P < 0.01, respectively). Of the 12 infants with AAIs > 1 g x kg(-1) x d(-1), only 1 infant was significantly catabolic (protein balance <-1 g x kg(-1) x d(-1)). There was no evidence of protein intolerance as determined by elevated creatinine (69 +/- 31 micromol/L), plasma urea nitrogen (6.7 +/- 2.53 mmol/L), or metabolic acidosis (pH: 7.36 +/- 0.05). CONCLUSIONS: Ill neonates can achieve a positive protein balance in the first days of life without laboratory evidence of protein toxicity.     

Behavioral assessment of acoustic parameters relevant to signal recognition and preference in a vocal fish

Acoustic signal recognition depends on the receiver's processing of the physical attributes of a sound. This study takes advantage of the simple communication sounds produced by plainfin midshipman fish to examine effects of signal variation on call recognition and preference. Nesting male midshipman generate both long duration (> 1 min) sinusoidal-like "hums" and short duration "grunts." The hums of neighboring males often overlap, creating beat waveforms. Presentation of humlike, single tone stimuli, but not grunts or noise, elicited robust attraction (phonotaxis) by gravid females. In two-choice tests, females differentiated and chose between acoustic signals that differed in duration, frequency, amplitude, and fine temporal content. Frequency preferences were temperature dependent, in accord with the known temperature dependence of hum fundamental frequency. Concurrent hums were simulated with two-tone beat stimuli, either presented from a single speaker or produced more naturally by interference between adjacent sources. Whereas certain single-source beats reduced stimulus attractiveness, beats which resolved into unmodulated tones at their sources did not affect preference. These results demonstrate that phonotactic assessment of stimulus relevance can be applied in a teleost fish, and that multiple signal parameters can affect receiver response in a vertebrate with relatively simple communication signals.     

Genetic control of natural killing and in vivo tumor elimination by the Chok locus

The molecular mechanisms underlying target recognition during natural killing are not well understood. One approach to dissect the complexities of natural killer (NK) cell recognition is through exploitation of genetic differences among inbred mouse strains. In this study, we determined that interleukin 2-activated BALB/c-derived NK cells could not lyse Chinese hamster ovary (CHO) cells as efficiently as C57BL/6-derived NK cells, despite equivalent capacity to kill other targets. This strain-determined difference was also exhibited by freshly isolated NK cells, and was determined to be independent of host major histocompatibility haplotype. Furthermore, CHO killing did not correlate with expression of NK1.1 or 2B4 activation molecules. Genetic mapping studies revealed linkage between the locus influencing CHO killing, termed Chok, and loci encoded within the NK gene complex (NKC), suggesting that Chok encodes an NK cell receptor specific for CHO cells. In vivo assays recapitulated the in vitro data, and both studies determined that Chok regulates an NK perforin-dependent cytotoxic process. These results may have implications for the role of NK cells in xenograft rejection. Our genetic analysis suggests Chok is a single locus that affects NK cell-mediated cytotoxicity similar to other NKC loci that also regulate the complex activity of NK cells.     

The MAS proto-oncogene is imprinted in human breast tissue

The human MAS proto-oncogene is situated at 6q25.3-q26, a region that is homologous to mouse chromosome 17 where two parentally imprinted genes (Mas and Igf2r) have previously been identified. We investigated the imprinting status of MAS in adult lesions to establish the imprinting status of this gene in humans, as certain imprinted genes are known to have altered imprinting phenotypes in cancer. Of 14 breast samples demonstrating a MAS RT-PCR product, 4 were informative for a polymorphic marker. In all 4 cases, expression of the MAS gene was found to be mono-allelic, indicating the presence of a functional imprint at this locus in human breast tissue.     

Evidence for the production of peroxynitrite in inflammatory CNS demyelination

Peroxynitrite, which is generated by the reaction of nitric oxide (NO) with superoxide, is a strong oxidant that can damage subcellular organelles, membranes and enzymes through its actions on proteins, lipids, and DNA, including the nitration of tyrosine residues of proteins. Detection of nitrotyrosine (NT) serves as a biochemical marker of peroxynitrite-induced damage. In the present studies, NT was detected by immunohistochemistry in CNS tissues from mice with acute experimental autoimmune encephalomyelitis (EAE). NT immunoreactivity was displayed by many mononuclear inflammatory cells, including CD4+ cells. It was also observed in astrocytes near EAE lesions. Immunostaining for the inducible isoform of NO synthase (iNOS) was also observed, particularly during acute EAE. These data strongly suggest that peroxynitrite formation is a major consequence of NO produced via iNOS, and implicate this powerful oxidant in the pathogenesis of EAE.     

Primary craniovertebral anomalies and the hindbrain herniation syndrome (Chiari I): data base analysis

This prospective study analyzes 100 patients with Chiari malformation and primary craniovertebral junction (CVJ) anomalies (3-66 years). Neurodiagnostic investigations employed tomography, gas myelography, CT and CT myelography, and MRI. Factors considered were reducibility, mode of encroachment, cerebrospinal fluid (CSF) dynamics and syringohydromyelia. Sixty-six patients with irreducible pathology underwent ventral or ventrolateral decompression and dorsal stabilization. Dorsal occipitocervical fixation was performed in reducible lesions that also required dorsal decompression (n = 34). Proatlas remnants were identified in 8 and atlas assimilation in 92 patients. Paramesial invagination was present in 20, syringohydromyelia in 46, and vertebral segmentation defects in 66 others. Completely reducible abnormalities were identified in 16 of 20 patients aged 2-14 years, and partially reducible abnormalities in 4 of 16 patients aged 14-20 years, 8 of 48 patients aged 20-40 years and 6 of 16 patients aged 40-60 years. The critical sagittal canal diameter at the foramen magnum was 19 mm. Twenty-two patients had previous posterior decompression and 27 had previous syrinx to subarachnoid shunt with delayed deterioration. Improvement occurred in all after ventral or ventrolateral decompression with resolution of the syringohydromyelia and normalization of CSF flow. We conclude that: (1) hindbrain herniation syndrome is frequently seen with fourth occipital sclerotome abnormalities; (2) Chiari malformation with craniovertebral abnormalities become symptomatic with a canal diameter of < 19 mm; (3) abnormal ventral bony pathology is reducible in children wit atlas assimilation and later becomes irreducible invagination, therefore early operation with fusion is recommended; (4) ventral decompression relieves brain stem, cerebellar symptoms and syringohydromyelia; (5) CSF studies with cine MRI shows reversal of craniospinal CSF dissociation after ventral CVJ decompression and; (6) craniovertebral anomalies associated with Chiari malformations must be addressed early and appropriately.     

Integrated health care and the advanced practice nurse

As state-designed Medicaid reforms are enacted and commercial insurance carriers begin to manage care, advanced practice nurses (APNs) must be ready to aggressively pursue opportunities for clinical participation. Understanding the contractual obligations of becoming a provider, as well as adopting strategies for successful participation in these emerging integrated networks, will be critical for APNs. Successful contracting requires a carefully defined set of practice activities and a willingness to become a team player in a complex organization.