Clinical and economic outcome of patients undergoing tracheostomy for prolonged mechanical ventilation in New York state during 1993: analysis of 6,353 cases under diagnosis-related group 483

OBJECTIVE: To examine and describe the relation between age and disposition in patients undergoing tracheostomy. DESIGN: Retrospective analysis of a statewide database. SETTING: All acute care hospitals in New York state. PATIENTS: All patients (n = 6,353) > or = 18 yrs of age who were discharged from the hospital during 1993 with a final diagnosis-related groups code of 483. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The final disposition, according to six disposition codes (other acute care facility, residential healthcare facility, other healthcare facility, home, home healthcare services, and death) was examined for the entire population. Cost per case was assumed to equal the average statewide Medicaid rate. An inverse relation between survival rate and age was observed, which resulted in an age-related increased cost per survivor. Also, survivors in older age groups had an increased rate of discharge to residential healthcare facilities. There was a negative, albeit less marked, effect of older age on the rates of survivors discharged to home and to other healthcare facilities. CONCLUSIONS: Care of patients who undergo tracheostomy for prolonged mechanical ventilation is expensive. The older the patient, the less satisfactory the outcome from an economic, clinical, and possibly social perspective.     

Characterizing relative intensity noise in InGaAsP-InP triangular ring lasers

This paper discusses relative intensity noise (RIN) characterization of triangular ring lasers, fabricated through a self-aligned dry etching process in InGaAsP-InP. Unusual low frequency noise enhancement was observed in each of the output beams, that is strongly dependent on the mirror backscattering strength. We explain the physical origin of the unusual RIN results as a partition noise effect between the two output beams of the ring laser, which can be best interpreted as superposition of two incoherent spatially bidirectional modes, generated by incoherent spontaneous emission photons traveling in clockwise and counterclockwise directions. This effect is unique to the ring laser geometry, and reported here for the first time. General noise predictions of our analysis are consistent with experimental measurements. This partition noise enhancement is expected to be present in the entire class of bidirectional semiconductor ring lasers, affecting the noise performance of not only the triangular ring laser, but also circular and square geometries, and possibly microdisk type lasers, in integrated photonic circuit applications.     

Changes in serum osteocalcin, plasma phylloquinone, and urinary gamma-carboxyglutamic acid in response to altered intakes of dietary phylloquinone in human subjects

The response of osteocalcin and other biochemical markers of vitamin K status to diets formulated to contain different amounts of phylloquinone was assessed in nine healthy subjects aged 20-33 y. Subjects resided in a metabolic ward for two 15-d cycles with a minimum of 6 wk between cycles. A mixed diet containing 100 micrograms phylloquinone/d was fed throughout both cycles; however, the phylloquinone content of one of the cycles was increased to a total of 420 micrograms/d on days 6 through 10 by fortifying corn oil in the diet with phylloquinone (supplemented diet). Total serum osteocalcin concentrations were not affected by either of the dietary treatments. The percentage of undercarboxylated osteocalcin increased an average of 28% over the 15-d cycle with the mixed diet (P < 0.05) and declined significantly an average of 41% with 5 d of the supplemented diet (day 6: 21.9 +/- 1.3%, day 11: 12.8 +/- 1.1%; P = 0.0001) with a rise after the return to the mixed diet (16.7 +/- 1.3%, P < 0.001). Plasma phylloquinone concentrations increased significantly with supplementation (day 6: 0.95 +/- 0.16 nmol/L, day 11: 1.40 +/- 0.29 nmol/L; P < 0.001) and then rapidly returned to presupplementation concentrations on returning to the mixed diet. Twenty-four-hour ratios of urinary gamma-carboxyglutamic acid to creatinine were unchanged with the supplemented diet; however, excretion declined to 91 +/- 2% of baseline after 10 d on the mixed diet (P = 0.01). These results show that undercarboxylated osteocalcin, plasma phylloquinone, and urinary gamma-carboxyglutamic acid excretion appear to be sensitive measures of vitamin K nutritional status because all of these variables were responsive to changes in dietary intake.     

A minimal, compartmental model for a dendritic origin of bistability of motoneuron firing patterns

Various nonlinear regenerative responses, including plateau potentials and bistable repetitive firing modes, have been observed in motoneurons under certain conditions. Our simulation results support the hypothesis that these responses are due to plateau-generating currents in the dendrites, consistent with a major role for a noninactivating calcium L-type current as suggested by experiments. Bistability as observed in the soma of low- and higher-frequency spiking or, under TTX, of near resting and depolarized plateau potentials, occurs because the dendrites can be in a near resting or depolarized stable steady state. We formulate and study a two-compartment minimal model of a motoneuron that segregates currents for fast spiking into a soma-like compartment and currents responsible for plateau potentials into a dendrite-like compartment. Current flows between compartments through a coupling conductance, mimicking electrotonic spread. We use bifurcation techniques to illuminate how the coupling strength affects somatic behavior. We look closely at the case of weak coupling strength to gain insight into the development of bistable patterns. Robust somatic bistability depends on the electrical separation since it occurs only for weak to moderate coupling conductance. We also illustrate that hysteresis of the two spiking states is a natural consequence of the plateau behavior in the dendrite compartment.     

Connective tissue growth factor. Friend or foe?

Connective tissue growth factor (CTGF) is a novel cysteine-rich, secreted peptide, which is implicated in human atherosclerosis and fibrotic disorders such as systemic scleroderma. CTGF is a member of the peptide family that includes serum-induced immediate early gene products, a v-src-induced peptide, and a putative proto-oncogene. The CTGF gene family is a modular protein and is conserved throughout evolution. CTGF mRNA has been found in the human, mouse, chicken, frog, and fly. The functions of the CTGF gene family include embryogenesis, wound healing, and regulation of extracellular matrix production. Human CTGF is undetectable in normal blood vessels but overexpressed in atherosclerotic lesions, suggesting an important role in atherogenesis.