Factors influencing choice between tracheostomy and prolonged translaryngeal intubation in acute respiratory failure: a prospective study

Hematologic parameters were studied in giant Canada geese (Branta canadensis maxima), mallard ducks (Anas platyrhynchos platyrhynchos) and various species of diving ducks at seasinal intervals throughout the year. Highest values for packed cell volume, hemoglobin content and erythrocyte counts were found in the winter and pre-nesting periods. Mean corpuscular volume and mean corpuscular hemoglobin varied inversely with these values.     

Enzymological studies of melanin concentrating hormone (MCH) and related analogues

1. Salmon melanin concentrating hormone (MCH) is a cyclic heptadecapeptide possessing the following primary structure: Asp-Thr-Met-Arg-Cys-Met-Val-Gly-Arg-Val-Tyr-Arg-Pro-Cys-Trp-Glu-Val. 2. In the fish, Synbranchus marmoratus, skin bioassay MCH5-15 is equipotent to MCH whereas MCH5-14, which comprises only the ring structure, is about 100-fold less active. 3. MCH and two fragment analogues, MCH5-15 and MCH5-14, were studied to determine their relative stability in the presence of fish serum and purified proteolytic enzymes, trypsin and alpha-chymotrypsin. 4. After 4 hr incubation in fish serum, MCH5-15 retained 1/100, MCH5-14 1/1000 and MCH only 6/1000 of the potency of the native hormone. 5. The three peptides were also very resistant to degradation by purified proteolytic enzymes involving the following relative order of resistance: MCH5-14 > MCH5-15 > MCH. MCH5-14 potency was not altered after a 1 hr incubation in either enzyme whereas MCH retained 1/10 and 4/100 of its original potency, and MCH5-15 retained 1/10 and 8/10 of its original potency, after 1 hr in trypsin and alpha-chymotrypsin, respectively.     

Cyclic neutropenia: report of a case with a 15-year follow up

Oropharyngeal dysphagia is a difficult clinical problem that is commonly found in patients with diffuse neurological or local laryngeal disorders. Gastroenterologists are frequently consulted regarding management of these patients. Diagnosis of specific pathophysiology is best accomplished with a combined approach, including barium video radiography and solid-state manometry. Therapy includes specific modalities where appropriate and mechanical manipulations aimed at prevention of aspiration, in consultation with a speech language pathologist.     

OVERLOAD RETARDATION OF FATIGUE CRACK GROWTH IN A 9%Cr 1%Mo STEEL AT ELEVATED TEMPERATURES

This paper describes an investigation into the effects of a single-peak tensile overload on fatigue crack propagation in a 9%Cr 1 %Mo steel. Overloads were applied during cycling at a constant stress intensity range (ΔK), and any consequent transients in growth rate were recorded. The severity of retardation rises as the magnitude of the applied overload is increased. The effect of temperature is complex, but a 525?C retardation is significantly less marked than at 25 or 225?C. Signs of crack face contact are seen on post-overload fracture surfaces, but there is little crack branching. The dominant cause of overload retardation in this steel appears to be plasticity-induced closure. At 525?C, post-overload dwell periods significantly reduce the severity of retardations. This is not observed at lower temperatures, indicating that the residual clamping stresses that lead to closure are gradually relieved at 525?C.     

In vitro superoxide production by hyaline cells of the shore crab Carcinus maenas (L.)

Routine clinical follow-up for distant metastatic disease among women with early stage breast cancer is of uncertain clinical benefit. In order to evaluate current practice patterns, we administered a mailed survey to a stratified random sample of physician members of the American Society of Clinical Oncology (ASCO) (N = 435). The survey assessed the frequency and motivation for ordering follow-up medical tests in asymptomatic postmenopausal women with stage I or II breast cancer. The response rate was 55%, distributed as 39% radiation oncologists, 32% medical oncologists, and 29% surgeons. In the first year after treatment, physicians performed, on average, one physical examination every 3 months, one blood panel (CBC, alkaline phosphatase and liver function tests) every 4 months, and one chest radiograph every 9 months. In addition, 38% of the respondents ordered CEA and 21% ordered CA 15-3 levels, 28% ordered bone scans, and less than 4% ordered CT scans, bone surveys, or bone marrow biopsies in the first year after treatment. A logistic regression analysis controlling for physician age, gender, sub-specialty, practice type, years of experience, number of breast cancer patients treated annually, geographic region, and community size, showed that surgeons were less likely to order blood tests (p < 0.001) and tumor markers (p < 0.0029) than medical oncologists in years 3 and 5 of follow-up. Compared to physicians practicing in the northeast, those from the midwest were less likely to order chest radiographs in year 3 of follow-up (p = 0.0028). Other provider characteristics had no significant effect on test ordering behavior. The results of this survey suggest that relatively uniform practice patterns in regard to the follow-up of postmenopausal women with early stage breast cancer exist among ASCO physicians.     

FATIGUE CRACK GROWTH FROM SMALL SEMI-ELLIPTIC HYDROGEN-INDUCED CRACKS IN QIN STEEL

Abstract— Small semi-elliptic hydrogen-induced cracks were produced in QIN (HY80) steel. Fatigue crack growth rate behaviour and threshold values for these cracks were investigated at several positive stress ratios ( R = 0.2 to 0.7) and compared with results from long through-cracks. At low R values the hydrogen-induced cracks gave higher thresholds, and lower crack growth rates at the same nominal Δ K value in the near threshold region. At high R values the growth rates of both crack types were almost identical. The results are explained by a combination of crack tip blunting and roughness induced closure of the intergranular hydrogen crack.     

The Two-Sheet Capacitive Jaumann Absorber

Many Jaumann absorber designs rely on purely resistive sheets spaced λ/4 apart, and the designs are based on the requirement that the voltage reflection coefficient and its derivatives vanish at the center frequency. The thickness of the absorber can be reduced and its bandwidth considerably expanded if the sheets are allowed to have capacitive reactances in addition to pure resistance. The bandwidth can be expanded even more by imposing different design criteria. We illustrate those advantages by invoking what we call a double-notch design process for a simple two-sheet absorber     

Electron paramagnetic resonance spectroscopic measurement of Mn2+ binding affinities to the hammerhead ribozyme and correlation with cleavage activity

Efficient phosphodiester bond cleavage activity by the hammerhead ribozyme requires divalent cations. Toward understanding this metal ion requirement, the Mn2+-binding properties of hammerhead model ribozymes have been investigated under dilute solution conditions, using electron paramagnetic resonance spectroscopy (EPR) to detect free Mn2+ in the presence of added ribozyme. Numbers and affinities of bound Mn2+ were obtained at pH 7.8 (5 mM triethanolamine) in the presence of 0, 0.1, and 1.0 M NaCl for an RNA-DNA model consisting of a 13-nucleotide DNA "substrate" hybridized to a 34-nucleotide RNA "enzyme" [Pley, H. W., Flaherty, K. M., and McKay, D. B. (1994) Nature 372, 68-74]. In 0.1 M NaCl, two classes of Mn2+ sites are found with n1 = 3.7 +/- 0.4, Kd(1) = 4 +/- 1 microM (type 1) and n2 = 5.2 +/- 0.4, Kd(2) = 460 +/- 130 microM (type 2). The high-affinity type 1 sites are confirmed for an active RNA-RNA hybrid (34-nucleotide RNA enzyme:13-nucleotide RNA substrate) by EPR measurements at low Mn2+ concentrations. Decreasing NaCl concentration results in an increased number of bound Mn2+ per hammerhead. By contrast, a binding titration in 1 M NaCl indicates that a single Mn2+ site with apparent Kd approximately 10 microM is populated in low concentrations of Mn2+, and apparent cooperative effects at higher Mn2+ concentrations result in population of a similar total number of Mn2+ sites (n1 = 8-10) as found in 0.1 M NaCl. Mn2+-dependent activity profiles are similar for the active RNA-RNA hybrid in 0.1 and 1 M NaCl. Correlation with binding affinities determined by EPR indicates that hammerhead activity in 0.1 M NaCl is only observed after all four of the high-affinity Mn2+ sites are occupied, rises with population of the type 2 sites, and is independent of Mn2+ concentrations corresponding to > 8-9 Mn2+ bound per hammerhead. Equivalent measurements in 1 M NaCl demonstrate a rise in activity with the cooperative transition observed in the Mn2+ binding curve. These measurements indicate that, over this NaCl concentration range, hammerhead ribozyme activity is influenced by population of a specific set of divalent cation sites.