National Beef Quality Audit: survey of producer-related defects and carcass quality and quantity attributes

To assess the then-current population of fed beef cattle for quality defects, the federally inspected beef steer and heifer slaughter in 28 packing plants was surveyed during a 3-mo period (October to December 1991). Data were collected over the course of 1 d of production at chain speed. Carcasses were selected randomly to include 50 and 10% of each lot on the slaughter floor and in the cooler, respectively. Slaughter floor defects evaluated were brand location and size, degree of bruising, grubs and injection sites, condemnation of offal, and the presence of mud and horns. USDA grade factors and other data were collected in the cooler. The distribution of hot-iron brand scars on the hide for the sample was as follows: cattle with no brand, 55.0%; cattle with butt brands, 29.9%; cattle with side brands, 13.8%; and cattle with shoulder brands, .8%. In addition, 83.3, 85.6, 76.6, 97.3, 99.9, and 99.8% of the carcasses had no superficial bruising in the chuck, rib, loin, round, brisket, and other areas of the carcass, respectively. The incidence of viscera condemnations for livers, lungs, tripe, and total viscera were 19.2, 5.1, 3.5, and .1%, respectively. Means for the carcass traits were as follows: USDA yield grade, 3.1; hot carcass weight, 344.7 kg; adjusted fat thickness, 1.5 cm; longissimus muscle area, 83.4 cm2; kidney, pelvic, and heart fat, 2.2%; USDA quality grade, high Select; marbling score, Small-minus; and overall maturity, A69.     

Ear canal reflectance in the presence of spontaneous otoacoustic emissions. I. Limit-cycle oscillator model

Allen et al. [Abstract in Eighteenth Midwinter Research Meeting of the Association for Research in Otolaryngology, Des Moines, IA (1995)] have found that the ear canal reflectance passes through a minimum around the frequency of a spontaneous otoacoustic emission (SOAE). They considered this result to constitute evidence against active nonlinear cochlear function as the basis for SOAEs. In order to investigate theoretically the expected behavior of ear canal reflectance in the neighborhood of a SOAE associated with an active-nonlinear cochlea, we use a simplified model in which the ear drum end of the ear canal is effectively terminated by a nonlinear-active element. Under the influence of a sinusoidal driver at the entrance of the ear canal, this element will, to a good approximation, either (1) oscillate at both the frequency of the driver (at which the reflectance is determined) and the SOAE (at a suppressed level, corresponding to nonentrainment), or (2) be entrained and only oscillate at the driving frequency. The magnitude of the nonlinear ear canal reflectance is found to exceed unity only at sufficiently low stimulus levels, and occurs under conditions of entrainment and nonentrainment of the spontaneous emission. Otherwise, the reflectance is less than unity and, as a function of frequency, has a minimum around the SOAE frequency.     

Extremely low-birth-weight children and their peers. A comparison of school-age outcomes

OBJECTIVE: To document 7-year developmental and educational outcomes in a cohort of predominantly white, middle-class, extremely low-birth-weight (ELBW, < 1000 g) children to address the incidence of increased developmental disability and the need for special educational services. DESIGN: Observational study. PATIENTS: Fifty-four ELBW children and 58 comparison children, who were matched for race, gender, and socio-economic status (30 with low birth weights [1500-2500 g] and 28 with birth weights > 2500 g). The ELBW cohort was drawn from 104 presurfactant survivors born between 1984 and 1986 and cared for in a single hospital. SETTING: Suburban, university-based tertiary referral center. MAIN OUTCOME MEASURES: Teachers' reports of classroom placement and special education services and tests of cognitive, motor, language, and visual-motor integration abilities were studied. RESULTS: Twenty-seven (50%) of 54 ELBW children were in regular classrooms with no special services compared with 21 (70%) of 30 in the low-birth-weight group and 27 (93%) of 28 in the full-term group, indicating a significant trend toward increasing need for special services with decreasing birth weight across the 3 groups (P < .001). The ELBW group scored significantly lower than the comparison groups on all tests, although generally within the average range. Seventy-nine percent of ELBW children had average cognitive scores, but they averaged 14 to 17 points lower than the 2 comparison groups. Twenty percent of the ELBW children had significant disabilities including cerebral palsy, mental retardation, autism, and low intelligence with severe learning problems. CONCLUSIONS: Even with optimal socioeconomic environments, 20% of ELBW children are significantly disabled, and 1 of every 2 ELBW children requires special educational services. Objective testing pinpointed weakness on all measures compared with matched peer groups.     

A homoallelic Gly317-->Asp mutation in ALPL causes the perinatal (lethal) form of hypophosphatasia in Canadian mennonites

Most drugs induce conditioned taste aversions and are therefore commonly supposed to produce nausea or sickness. Paradoxically, some drugs appear to lose induction capability when made to serve as a cue for a second drug that produces more severe sickness, perhaps through selective association with a hypothetical homeostatic or antisickness aftereffect of sickness. Using drug-drug pairings had made antisickness conditioning theory difficult to validate. We report here that rotation serves in lieu of a drug cue in rats. Rotation-drug pairings eliminate drug interactions and enable the sorts of parametric manipulations required to validate the theory. By postulating a common sickness mechanism to explain both taste aversion and aversion failure, the theory places the phenomenon within an adaptive evolutionary framework. Successful application could yield a direct countermeasure to severe nausea in clinical settings.     

Use of an intramedullary hip-screw compared with a compression hip-screw with a plate for intertrochanteric femoral fractures. A prospective, randomized study of one hundred patients

One hundred elderly patients who had an intertrochanteric femoral fracture were randomized to treatment with a compression hip-screw with a plate (fifty patients) or a new intramedullary device, the intramedullary hip-screw (fifty patients). All patients were followed prospectively for one year or until death. A detailed assessment of the functional status and the plain radiographs of the hip was performed one, three, six, and twelve months postoperatively. The two treatment groups were strictly comparable. The operative time needed to insert the intramedullary hip-screw was significantly greater than that needed to insert the compression hip-screw with the plate (p = 0.02), but use of the intramedullary hip-screw was associated with less estimated intraoperative blood loss (p = 0.011). The prevalence of perioperative complications, such as bronchopneumonia, cardiac failure, and urinary tract infection, was comparable in the two treatment groups. There were one intraoperative fracture of the femoral shaft and two intraoperative fractures of the greater trochanter in the group managed with the intramedullary hip-screw. One patient had pulling-out of the compression hip-screw on the seventh postoperative day. Four patients had a trochanteric wound hematoma, without infection, after insertion of an intramedullary hip-screw. All but one of the fractures healed. The one non-union, which was in a patient who had a compression hip-screw, was treated with a hemiarthroplasty. The mortality rate was similar in the two treatment groups. The patients who had an intramedullary hip-screw had, on the average, significantly better mobility at one (p < 0.0001) and three months (p = 0.0013) postoperatively. This difference was no longer seen at six and twelve months, although the patients who had an intramedullary hip-screw still had significantly better walking ability outside the home at those time-periods (p = 0.05). The compression hip-screw was removed from two patients because of pain in the mid-portion of the thigh, which had begun after consolidation of the fracture. Fourteen patients who had an intramedullary hip-screw had cortical hypertrophy at the level of the tip of the nail at twelve months postoperatively. Cortical hypertrophy was significantly related to the use of two interlocking screws (p = 0.02). Six of these patients also had pain in the mid-portion of the thigh, and the nail had been locked with two screws in five of them. Three of the six patients had the hardware removed because of the pain, and the symptoms resolved. A seventh patient had pain without cortical hypertrophy. The intramedullary hip-screw device was associated with significantly less sliding of the lag-screw and subsequent shortening of the limb in the region of the thigh (p = 0.012 and 0.019, respectively); these differences were more pronounced when the unstable fractures in the two treatment groups were compared (p < 0.001).     

Glaxo/MRS Young Investigator Medal. Molecular studies on adenosine deaminase deficiency and hereditary haemorrhagic telangiectasia

Factorially arranged experiments were designed to study prefreeze packed cell volume (PCV) changes and associated percentages of motile and unstained bull sperm in simple macromolecule-free Tyrode's solution and egg yolk-Tris (EYT), varying in osmolarity, and with addition of rapidly permeating cryoprotectants, glycerol and 1,2-propanediol, and nonpermeating substances, sucrose and NaCl. The percentage of motile and unstained sperm was assessed after resuspending sperm in 300 mOsm/L Tyrode's solution. At 25 degreesC PCV increased in Tyrode's solution as osmolarity was decreased from 250 to 150 mOsm/L and decreased as Tyrode's solution was increased to 400 mosmol/L. The relationship of PCV to the reciprocal of the osmolarity was essentially linear over the range of 150 to 400 mOsm/L, but PCV did not decrease further in solutions ranging from 500 to 1000 mOsm/L. The percentage of motile sperm declined to zero in Tyrode's solution at 700 mOsm/L, but 40% of the sperm were still unstained in 1000 mOsm/L solutions. The addition of glycerol or 1,2-propanediol had little effect on PCV. With glycerol or 1,2-propanediol added to 308 mOsm/L Tyrode's solution to give a total of 1267 mOsm/L, there were 49 and 56% motile sperm, respectively, compared to 1% with NaCl added to give 787 mOsm/L. The PCV and percentage of motile sperm suspended in EYT responded to osmotic changes similar to those reported for Tyrode's solution at both 25 and 5 degreesC. Some sperm remained motile after initial exposure to 800 mOsm/L solutions. These findings may have application in improving bull sperm cryopreservation.     

Effects of surfactant distribution and ventilation strategies on efficacy of exogenous surfactant

The effects of both surfactant distribution patterns and ventilation strategies utilized after surfactant administration were assessed in lung-injured adult rabbits. Animals received 50 mg/kg surfactant via intratracheal instillation in volumes of either 4 or 2 ml/kg. A subset of animals from each treatment group was euthanized for evaluation of the exogenous surfactant distribution. The remaining animals were randomized into one of three ventilatory groups: group 1 [tidal volume (VT) of 10 ml/kg with 5 cmH2O positive end-expiratory pressure (PEEP)]; group 2 (VT of 5 ml/kg with 5 cmH2O PEEP); or group 3 (VT of 5 ml/kg with 9 cmH2O PEEP). Animals were ventilated and monitored for 3 h. Distribution of the surfactant was more uniform when it was delivered in the 4 ml/kg volume. When the distribution of surfactant was less uniform, arterial PO2 values were greater in groups 2 and 3 compared with group 1. Oxygenation differences among the different ventilation strategies were less marked in animals with the more uniform distribution pattern of surfactant (4 ml/kg). In both surfactant treatment groups, a high mortality was observed with the ventilation strategy used for group 3. We conclude that the distribution of exogenous surfactant affects the response to different ventilatory strategies in this model of acute lung injury.     

Involvement of the pleckstrin homology domain in the insulin-stimulated activation of protein kinase B

Involvement of the pleckstrin homology (PH) domain in the insulin-stimulated activation of protein kinase B (PKB) was investigated in human embryonic kidney 293 cells. Different PKB constructs that contain mutations or deletions in the PH domain were transfected into cells, and the results on the basal and insulin-induced kinase activities were analyzed. Deletion of the entire PH domain (DeltaPH-PKB) did not impair the kinase activity; in contrast, the basal activity was elevated with respect to wild-type PKB. In addition, DeltaPH-PKB was responsive to insulin, and as for wild-type PKB, this was dependent on phosphoinositide 3-kinase. By contrast, a point mutation within the PH domain that impairs phospholipid binding (R25C) resulted in a construct that was not responsive to insulin. However, this defect was overcome by mutations that mimic the phosphorylation state of the active kinase. The increase in the basal activity of DeltaPH-PKB was shown to be due to an elevation in the level of phosphorylation of this construct. In addition, the subcellular localization of DeltaPH-PKB, as determined by both immunofluorescence and fractionation, was predominately cytosolic, and DeltaPH-PKB was present in the plasma membrane at much lower levels compared with wild-type PKB. These data show that phosphorylation is the major factor regulating the activity of PKB and that either removal of the PH domain or binding of phospholipids is required to permit this phosphorylation. In addition, membrane localization does not appear to be required for the activation process, but instead, binding of PKB to membrane phospholipids permits a conformational change in the molecule that allows for phosphorylation.     

Malignant progenitors from patients with acute myelogenous leukemia are sensitive to a diphtheria toxin-granulocyte-macrophage colony-stimulating factor fusion protein

We have previously demonstrated that human granulocyte-macrophage colony-stimulating factor (GM-CSF) fused to a truncated diphtheria toxin (DT388-GMCSF) kills acute myelogenous leukemia (AML) cell lines bearing the GM-CSF receptor. We now report that exposure of malignant cells from 50 different patients with AML for 48 hours in culture to DT388-GMCSF reduces by a median of 1.6 logs (range, 0 to 3.7 logs) the number of leukemic cells capable of forming colonies in semisolid media (leukemic colony-forming cells [CFU-L]) with a median IC50 of 3 x 10(-12) mol/L (range, 5 to >4,000 x 10(-12) mol/L). Furthermore, the cell kill is dependent on the presence of high-affinity GM-CSF receptors on leukemic blasts, because CFU-L from 27 of 28 AML samples expressing > or = 35 GM-CSF receptors per cell were inhibited by the toxin, whereas the colony growth from all 4 leukemic samples (2 AML, 1 acute lymphoblastic leukemia [ALL], and 1 prolymphocytic leukemia [PLL]) that had less than 35 receptors per cell was unaffected by the drug. Sensitivity of CFU-L to DT388-GMCSF was seen regardless of the clinical responsiveness of the patient's leukemia to standard chemotherapy agents. In contrast, clonogenic cells from normal bone marrow formed colonies at near control numbers after exposure to much higher toxin concentrations (4 x 10(-9) mol/L) than those required to kill CFU-L from most patients. Thus, leukemic progenitors isolated directly from the peripheral blood of most AML patients show the same sensitivity to DT388-GMCSF as previously demonstrated for AML cell lines. Under the same conditions of exposure, normal hematopoietic progenitors are relatively unaffected by DT388-GMCSF, suggesting its potential as a therapeutic agent in AML.