Dynamics of culling for Jersey, Holstein, and Jersey × Holstein crossbred cows in large multibreed dairy herds.

The objective of this observational study was to describe and compare the dynamics of reason-specific culling risk for the genetic groups Jerseys (JE), Holsteins (HO), and Jersey × Holstein crossbreds (JH), considering parity, stage of lactation, and milk yield, among other variables, in large multibreed dairy herds in Texas. The secondary objective was to analyze the association between survival and management factors, such as breeding and replacement policies, type of facilities, and use of cooling systems. After edits, available data included 202,384 lactations in 16 herds, ranging from 407 to 8,773 cows calving per year during the study period from 2007 to 2011. The distribution of lactation records by genetic group was 58, 36, and 6% for HO, JE, and JH crosses, respectively. Overall culling rates across breeds were 30.1, 32.1, and 35.0% for JH, JE, and HO, respectively. The dynamics of reason-specific culling were dependent on genetic group, parity, stage of lactation, milk yield, and herd characteristics. Early lactation was a critical period for "died" and "injury-sick" culling. The risk increased with days after calving for "breeding" and, in the case of HO, "low production" culling. Open cows had a 3.5 to 4.6 times greater risk for overall culling compared with pregnant cows. The odds of culling with reason "died" within the first 60 d in milk (DIM) were not significantly associated with genetic group. However, both JE and JH crosses had lower odds of live culling within the first 60 DIM compared with HO cows (OR=0.72 and 0.82, respectively). Other cow variables significantly associated with the risk of dying within the first 60 DIM were cow relative 305-d mature equivalent (305ME) milk yield, parity, and season of calving. Significant herd-related variables for death included herd size and origin of replacements. In addition to genetic group, the risk of live culling within 60 DIM was associated with cow-relative 305ME milk yield, parity, and season of calving. Significant herd-related variables for live culling included herd-relative 305ME milk yield, herd size, type of facility, origin of replacement, and type of maternity. Overall, reason-specific culling followed similar patterns across DIM in the 3 genetic groups.

Arrayed primer extension: solid-phase four-color DNA resequencing and mutation detection technology.

The technology and application of arrayed primer extension (APEX) is presented. We describe an integrated system with DNA chip and template preparation, multiplex primer extension on the array, fluorescence imaging, and data analysis. The method is based upon an array of oligonucleotides, immobilized via the 5' end on a glass surface. A patient DNA is amplified by PCR, digested enzymatically, and annealed to the immobilized primers, which promote sites for template-dependent DNA polymerase extension reactions using four unique fluorescently labeled dideoxy nucleotides. A mutation is detected by a change in the color code of the primer sites. The technology was applied to the analysis of 10 common beta-thalassemia mutations. Nine patient DNA samples, each of which carries a different mutation, and four wild-type DNA samples were correctly identified. The signal-to-noise ratio of this technology is, on the average, 40:1, which enables the identification of heterozygous mutations with a high confidence level. The APEX method can be applied to any DNA target for efficient analysis of mutations and polymorphisms.

Reduction of lung dust burden in pneumoconiosis by whole-lung lavage.

Pneumoconioses are characterized as irreversible, progressive respiratory diseases. No effective therapy exists to prevent progression of these diseases. Whole-lung lavage (WLL) might limit the rate of disease progression through the removal of dust, inflammatory cells, and cytokines. We performed WLL on a 54-year-old underground miner employed as a motorman and roof bolter and a 55-year-old driller at a surface coal mine. Both demonstrated normal lung function and chest radiographs showing ILO profusion category 2 nodular interstitial changes. From Subject 1, we recovered 5.24 x 10(8) cells (90% macrophages) from the right lung and 3.45 x 10(8) cells (94% macrophages) from the left lung. WLL removed 1.82 g of mineral dust (non-coal) on the right and 1.64 g on the left. From Subject 2, we recovered 7.49 x 10(8) cells (46% macrophages) from the right and 9.78 x 10(8) cells (69% macrophages) from the left lung. WLL removed 0.40 g of mineral dust on the right and 0.53 g on the left. Proinflammatory cytokines, growth factors, and cellular enzymes were also recovered. In cases of pneumoconiosis, WLL is capable of removing relatively large quantities of dust, cells, and soluble materials from the lungs. Only long-term follow-ups of individuals with progressive dust-induced disease who receive WLL therapy in the context of a clinical trial will provide information regarding the importance of removing mineral dust and inflammatory cells from the lung.

Does local irradiation affect gastric emptying in humans?

The authors measured gastric emptying in 13 patients undergoing radiation therapy to the chest, abdomen, or pelvis for nongastrointestinal cancer to investigate whether gastric emptying (GE) was altered by this therapy. Symptoms and weight were monitored at regular intervals. Patients served as their own controls and were compared to a group of healthy subjects. When studied prior to radiation therapy (baseline), cancer patients had a gastric emptying rate that was similar to a healthy control group (t1/2 mean+/-SEM 92.0+/-15.3 vs. 80.4+/-8.2 min). Irradiation did not change the emptying rate, either after the first dose (early) of 180 cGy (t1/2 99.5+/-17.9) or after 2 weeks of therapy (late) with 3000 cGy (t1/2 75.5+/-7.3). There was no correlation of radiation field or tumor type with gastric emptying rate. Two of the 13 patients experienced nausea and vomiting during their course of radiation, but their gastric emptying was unchanged from baseline.

Simulations of passive properties and action potential conduction in an idealized bullfrog atrial trabeculum.

This study investigates the properties of a distributed parameter model of an idealized trabeculum of cardiac muscle surrounded by a resistive-capacitive trabecular sheath. A mathematical approach is developed that permits the direct solution for the absolute potential in each medium [i.e., the intracellular (Vi), interstitial (Ve), and external (Vo) potentials), as opposed to obtaining solutions for the transmembrane potential V (where V identical to Vi-Ve). The mathematical description of the underlying individual cell is based upon quantitative whole-cell voltage-clamp measurements in bullfrog atrial myocytes. "Reduced" or "simplified" cell membrane models that lack the complete complement of transmembrane currents are compared with regard to their accuracy in representing the root, upstroke, and plateau regions of the propagated action potential in the complete model. The results show that a reduced cell membrane model must contain the sodium current INa, calcium current ICa, and background-rectifying K+ current IK1. A cell membrane model that contains a linear background K+ current IL instead of IK1 results in much poorer approximation to the upstroke, plateau, and conduction velocities of an action potential. The effects of varying the resistive-capacitive parameters of the trabecular sheath on both the passive properties (the time and space constants and the input resistance) and conduction parameters (time and space constants of the foot and conduction velocity of the action potential) of the trabeculum are also investigated. These simulations show that electrical activity within the trabeculum is much more sensitive to variations in the resistive component than in the capacitive component of the sheath. The trabecular sheath reduces the extracellular resistance seen by the cell by shunting current away from highly resistive interstitial medium into the volume conductor medium, which is of low resistance, and thereby increases conduction velocity. Finally, the addition of the cholinergic neurotransmitter acetylcholine to the extracellular medium reduces both the space constant of the trabeculum and the conduction velocity of propagated electrical activity.

Effects of soil fumigants and aldicarb on corky ringspot disease and trichodorid nematodes in potato.

In 1982 and 1983 the soil fumigants ethylene dibromide (EDB), EDB + chloropicrin, and 1,3-dichloropropene (1,3-D) applied with one or three chisels per row were evaluated singly and in combination with aldicarb on potato, Solanum tuberosum cvs. Atlantic and Sebago, for control of trichodorid nematodes and potato corky ringspot disease (CRS). In 1982 dosages per chisel for EDB, EDB + chloropicrin, and 1,3-D were 16.8, 23.9, and 56.1 liters/ha, respectively. EDB was applied at 12.6 liters per chisel per ha in 1983. Aldicarb was applied at 3.4 kg a.i./ha in-the-row. Differences (P

Effects of Soil Fumigants and Aldicarb on Bacterial Wilt and Root-knot Nematodes in Potato.

Preplant soil applications of oxamyl to shade grown tobacco in Globodera tabacum-infested field soil increased green leaf yields over untreated plots by 10.7 and 21.0% for 2.2 and 6.7 kg a.i. oxamyl/ha, respectively. Green leaf yield was negatively correlated (r = -0.60, P = 0.04) with initial G. tabacum density, which ranged from 33 to 154 second-stage juveniles (J2)/cm(3) soil. Numbers of G. tabacum J2 and developing juveniles and adults (J3-adults) per gram root were fewer in plants from oxamyl-treated plots than in plants from untreated plots. Numbers of J2 in roots 4, 6, and 8 weeks after transplanting were reduced by 80, 89, and 4%, respectively, and numbers of J3-adults were reduced by 96, 89, and 21%, respectively, in high-rate oxamyl plots, compared with untreated plots. Globodera tabacum reproduction, as measured by the ratio of final to initial soil densities, was less in oxamyl-treated plots than in untreated plots.

Effects of soil fumigants and aldicarb on nematodes, tuber quality, and yield in potato.

Efficacy of the fumigants ethylene dibromide (EDB), EDB + chloropicrin, and 1,3-dichloropropene (1,3-D) applied with one or three chisels per row, singly or in combination with aldicarb, was evaluated in 1982 and 1983 on potato (Solanum tuberosum) cultivars Atlantic and Sebago for control of several nematodes, including Belonolaimus longicaudatus, Meloidogyne incognita, and trichodorids. Generally, nematode populations were lowest following application of fumigants with three chisels per row, following EDB or EDB + chloropicrin, and when fumigants were applied in combination with aldicarb. These treatment combinations also resulted in highest yields in 1983. Cosmetic appearance of tubers was improved (P

Control of Nematodes and Soil-borne Diseases in Florida Potatoes with Aldicarb and 1,3-D.

Yields of U.S. Size A potato tubers were increased by 1,3-dichloropropene (1,3-D) (56 liters/ha) and 1,3-D (56 liters/ha) + aldicarb (3.4 kg/ha) in 1982 and 1983 and by aldicarb (3.4 kg/ha) in 1982. Treatments that included aldicarb provided the best control of corky ringspot disease, whereas those including 1,3-D were more effective against bacterial wilt. The most effective nematode control (nematodes included Meloidogyne incognita, Belonolaimus longicaudatus, trichodorids, Criconemella ornata, Tylenchorhynchus claytoni, and Helicotylenchus sp.) was provided by the combination of 1,3-D + aldicarb.

A Study of Equilibrium in Argon Arcs.

The intensities of the 7147 Å Ar i and 4806 Å Ar ii lines obtained from wall-stabilized arcs at pressures of 0.2 to 5 atm are presented in an Olsen-Richter diagram. Departures from equilibrium are evident at electron densities below 5 × 1016 cm-3. The assumption of equilibrium at higher electron densities leads to transition probabilities in fair agreement with lifetime measurements.

Transition Probabilities in Argon I.

In order to derive transition probabilities from intensity measurements of Ar I lines made by Dieke and Crosswhite, new transition probabilities for 26 lines from high levels in Ar I have been measured in a high current constricted arc. With these data, relative level populations of Ar I in Dieke and Crosswhite's rnicrewave discharge are determined and transition probabilities for 240 lines of Ar I in the wavelength range 4100 to 9800 Å are derived. The new values are compared with other published values.

A model of the phase-sensitivity of the pacemaking cell in the bullfrog heart.

In this study, mathematical models of the bullfrog sinus venosus (SV) pacemaker cell (Rasmusson et al., 1990, Am. J. Physiol. 259, H352-H369) and the ACh-sensitive K+ channel (Shumaker et al., 1990, Biophys. J. 57, 567-576) are combined to simulate the response of the SV myocyte to brief hyperpolarizing currents or acetylcholine (ACh) pulses. These simulations provide an ionic basis for the interpretation of the response of this pacemaker cell to either single perturbation or periodic stimuli. The model predicts that the effects of ACh stimulation on the pacemaker cycle length are dependent both on the phase and temporal characteristics of the [ACh] waveform. For example, the simulations show that (1) although ACh normally has an inhibitory effect on the pacemaker model, for cases where the rise time and duration of the [ACh] waveform are sufficiently brief, ACh can paradoxically accelerate the beat in which a single stimulus is given; (2) the SV pacemaker normally exhibits type 1 (odd) phase-resetting in response to ACh delivery, however type 0 (even) phase-resetting behavior may be exhibited when the [ACh] waveform is large enough and has a very fast rise time; and (3) the SV pacemaker may become phase-locked to a repetitive ACh stimulus applied with either a constant period or coupling interval. In the latter case, this entrainment phenomenon has implications for the control of the cardiac pacemaker by a neural oscillator (e.g. located in the medullary cardiovascular control center) which provides input to the pacemaker cell via the vagus nerve. In these regions of capture, repetitive ACh stimulation produces a well-known paradoxical accelerative effect on the SV pacemaker cell, similar to that seen in a variety of other species.

A model of beta-adrenergic effects on calcium and potassium current in bullfrog atrial myocytes.

A model of beta-adrenergic and muscarinic cholinergic effects on the bullfrog atrial myocyte has been developed to simulate the dose-dependent effects of isoprenaline (Iso) on the action potential duration (APD); i.e., low doses of Iso lengthen the APD, whereas high doses shorten the APD. In this model, the reduction in APD is the result of 1) calcium-dependent inactivation of calcium current (ICa) resulting from the enhancement of ICa by Iso and 2) an enhancement of potassium current (IK) due to both an Iso-induced increase in the rate of activation of IK and an increase in peak action potential height. The effect of acetylcholine (ACh) is simulated by a reduction in the Iso-induced increase in ICa and IK through a reduction in relative adenosine 3',5'-cyclic monophosphate concentration ([cAMP]), as well as activation of the ACh-sensitive potassium current. At low [Iso] levels in the presence of a high [ACh], the muscarinic cholinergic effects dominate the beta-adrenergic change. However, for a large [Iso] and a small [ACh], this pattern of changes in transmembrane currents is different; in this case the model predicts that ACh can actually increase APD.

Mutation detection by solid phase primer extension.

A mutation analysis method based upon a wild-type DNA sequence is presented. Oligonucleotides were utilized for primer extension by T7 DNA polymerase to discriminate between wild-type and mutant sequences in two solid phase approaches. 1. Oligonucleotides were annealed to an immobilized template, extended with fluorescent dideoxynucleotides (ddNTPs), and analyzed on an automated fluorescent DNA sequencer. The oligonucleotide length identified the known mutation site, and the fluorescence emission of the ddNTP identified the mutation. 2. Template DNA was annealed to an oligonucleotide array, extended with alpha-32P dNTPs, and analyzed with a Phosphor Imager. The grid position of the oligonucleotide identified the mutation site and the extended base identified the mutation.

A model of the muscarinic receptor-induced changes in K(+)-current and action potentials in the bullfrog atrial cell.

A model is formulated for characterizing the behavior of the acetylcholine (ACh)-sensitive K+ membrane channel (muscarinic channel) in bullfrog atrial myocytes. Parameters of the muscarinic current model are chosen in fit available data from the literature on bullfrog atrial myocytes (3, 4, 45). This model is subsequently incorporated into a large mathematical model of the bullfrog myocyte that is based on quantitative whole-cell voltage clamp data (40). Simulations are conducted on the active atrial cell model in bathing media containing ACh at different concentrations to explore the effect of this muscarinic channel on the electrical behavior of the myocyte. The model predicts a progressive shortening of the action potential with increasing [ACh], as well as an indirect influence of the muscarinic K+ current on the other membrane currents of the atrial cell. Interpretation of the simulation results provides suggestions for the probable mechanisms underlying the shortening of the action potential due to activity of the muscarinic channel. Specifically, the model predicts that with an increase in ACh concentration: (a) the outward muscarinic current, IK,ACh(t), increases in magnitude but shortens in duration; (b) the calcium current, ICa(t), may increase in magnitude, but when it does so it decreases in duration compared with the control conditions; (c) the intracellular Ca2+ concentration [Ca2+]i waveform during the action potential decreases in both magnitude and duration. Because the contractile activity of the cell is controlled by the [Ca2+]i waveform, the model predicts a decrease in contractile strength with an increase in ACh concentration in the bathing medium; i.e., a negative inotropic effect.

Differential sensitivities of viruses in red cell suspensions to methylene blue photosensitization.

BACKGROUND: Previous studies explored the feasibility of using the photosensitizer methylene blue (MB) as a virucidal agent in red cell suspensions. Under treatment conditions (5 microM [5 mumol/L] MB, 3.4 x 10(4) J/m2) that resulted in more than 6 log10 inactivation of vesicular stomatitis virus (VSV) or of the enveloped bacteriophage phi 6, red cell membrane alterations were observed. Increased red cell ion permeability and the binding of plasma proteins to the red cell surface were the most sensitive indicators, which varied in a dose-dependent fashion. STUDY DESIGN AND METHODS: Inactivation of three additional extracellular viruses and intracellular human immunodeficiency virus type 1 (HIV-1) was assessed after MB phototreatment of red cell suspensions. Potassium leakage and IgG binding also were characterized in MB-treated red cell suspensions that were exposed to low-fluence light (6 x 10(3) J/m2). RESULTS: Different viruses exhibit a wide range of sensitivities to MB photoinactivation. For example, phototreatment conditions (5 microM [5 mumol/L] MB, 3.4 x 10(4) J/m2) that inactivated more than 6 log10 of VSV did not inactivate the nonenveloped picornavirus, encephalomyocarditis virus. In contrast, lower fluences (6 x 10(3) J/m2) inactivated approximately 5 log10 or more of Sindbis virus and approximately 4log10 of extracellular HIV-1. These less stringent phototreatment conditions (5 microM [5 mumol/L] 6 x 10(3) J/m2) caused lower rates of red cell potassium leakage (reduction by 6-fold) and little or no binding of plasma proteins to the red cell surface, compared to values observed previously with higher fluences. However, neither 6 x 10(3) nor 4.1 x 10(4) J per m2 fluences resulted in any inactivation of intracellular HIV as represented by changes in the amount of p24 antigen produced during co-culture of actively infected H9 cells. CONCLUSION: MB-based protocols would require the use of high-efficiency (> 6log10) white cell-reduction filters or additional inactivation steps to deplete or inactivate intracellular virus.

Inactivation of free and cell-associated human immunodeficiency virus in platelet suspensions by aminomethyltrimethylpsoralen and ultraviolet light.

BACKGROUND: It has previously been reported that 40 micrograms per mL of aminomethyltrimethylpsoralen (AMT) plus 2.4 to 7.2 J per cm2 of ultraviolet A (UVA) light inactivated 4 to 6 log10 of several model viruses in platelet suspensions. This inactivation was achieved while satisfactory levels of platelet count, pH, morphology, aggregation, and hemostatic effectiveness were maintained. STUDY DESIGN AND METHODS: The efficacy of this procedure for inactivating free and intracellular human immunodeficiency virus (HIV), including integrated proviral sequences, was studied. RESULTS: The kinetics of inactivation for free HIV (4-5 log10 kill with 1.2-4.8 J/cm2) were similar to those obtained for the previously studied viruses. For studies on cell-associated virus, H9 cells productively infected with HIV were added to platelet suspensions and treated with the above regimen of AMT and UVA. The phototreated cells were then cocultivated with uninfected H9 cells for 4 weeks and supernatants were assayed by enzyme-linked immunosorbent assay for HIV p24. No evidence of HIV replication was detectable for cells receiving as little as 2.4 J per cm2 of UVA irradiation in the presence of AMT. Further, it has been demonstrated that stably integrated sequences from the HIV proviral env gene can no longer be amplified by polymerase chain reaction after 1.2 J per cm2 of UVA (with 40 micrograms/mL AMT) exposure. CONCLUSION: These data suggest that AMT and UVA is an effective antiviral treatment for free and cell-associated HIV in platelet suspensions.

A controlled trial of 6-methylprednisolone in acute alcoholic hepatitis. With a note on published results in encephalopathic patients.

In a prospective double-blind study, 27 patients with alcoholic hepatitis were randomized for 6-methylprednisolone (12 patients) or placebo treatment (15 patients). The mortality was 50% among steroid treated patients and 47% in the control group (P less than .05). The role of liver biopsy feasibility at selection is emphasized since the mortality in this group was 10% as opposed to 71% when the procedure was contraindicated (P less than .01). Complications in the steroid-treated subjects were similar quantitatively and qualitatively to those observed in the control series.