Probing Loop-Mediated Isothermal Amplification (LAMP) targeting two gene-fragments of rose rosette virus

This study explores the development of Loop-mediated isothermal amplification (LAMP) for detection of rose rosette virus (RRV), a technique with the potential to be translated to rose nurseries. RRV is a negative-sense, single-stranded RNA virus which is a member of the genus Emaravirus (Family Fimoviridae) and the causal agent of the rose rosette disease (RRD). Although RRV symptoms are characteristics, early visual diagnosis of RRD can be misleading and confusing since it may appear like herbicide damage. Moreover, it may take incubation time for symptoms to appear after virus infection. Two sets of RRV gene sequences RNA3 and RNA4 were analyzed and two sets of four LAMP primers were designed. The direct antigen-capture method for direct trapping of RRV in plastic was used for RNA extraction followed by cDNA synthesis. RT-LAMP reactions were for 1 hour at 64°C (RRV-P3) and 66.5°C (RRV-P4) using either a thermocycler or a portable dry bath. RT-qLAMP was also optimized using DNA polymerase GspSSD LD using the same RRV sets of primers. RRV was detected in symptomatic and non-symptomatic RRD tissue from Oklahoma. The limit of detection (LoD) was 1pg/μL and 1 fg/μL using Bst 2.0 LAMP and GspSSD LD quantitative LAMP, respectively. In visual colorimetric pre- and post-reactions, the LoD was 10 pg/μL and 0.1 pg/μL using hydroxy naphthol blue (HNB, 120 μM) and SYBR green I (1:10 dilution), respectively. No cross-reactivity was detected in the RT-LAMP reaction testing cDNAs of eight commonly co-infecting rose viruses and one virus taxonomically related to RRV. Four different dyes were tested, and visible colorimetric reactions were obtained with RT-LAMP Bst 2.0 combined with SYBR I or HNB. RT-qLAMP with GspSSD2.0 offers LoD equal to RT-PCR and it is faster since it works with RNA directly.

Preweaned heifer management on US dairy operations: Part V. Factors associated with morbidity and mortality in preweaned dairy heifer calves

The objective of this study was to evaluate morbidity and mortality in preweaned dairy heifer calves based on different health, feeding, and management practices, as well as environmental factors. This study was conducted as part of the calf component of the National Animal Health Monitoring System's Dairy 2014 study, which included 104 dairy operations in 13 states. The calf component was an 18-mo longitudinal study focused on dairy heifer calves from birth to weaning; data were collected on 2,545 calves. The percentage morbidity for all calves enrolled in the study was 33.9%. Backward elimination model selection was used after univariate screening to determine which management practices and environmental factors significantly affected morbidity and mortality. The final morbidity model included birth weight, serum IgG concentration, ventilation type, and average temperature-humidity index (THI) during the preweaning period. After controlling for other independent variables in the model, calves born at a higher birth weight had a lower predicted risk of morbidity than calves with a lower birth weight. An increase in serum IgG concentration was associated with decreased morbidity. Calves housed in positive- or cross-ventilated systems had a 2.2 times higher odds of developing disease compared with calves housed in natural ventilation systems. Average THI during the preweaning period was inversely correlated with morbidity; as THI increased, the predicted morbidity risk decreased. The percent mortality for all calves enrolled in the study was 5.0%. The final mortality model included birth weight, serum IgG concentration, amount of fat/day in the liquid diet, and morbidity. After controlling for other independent variables in the model, calves born at a higher birth weight had a lower risk of mortality. An increase in serum IgG concentration decreased the risk of mortality. The odds of mortality were 3.1 times higher in calves fed ≤0.15 kg of fat/d in the liquid diet compared with calves fed ≥0.22 kg of fat/d. The odds of mortality were 4.7 times higher in calves that experienced any disease throughout the preweaning period than in calves with no disease. In summary, morbidity and mortality were both associated with birth weight and serum IgG concentration. Additionally, morbidity was associated with ventilation type and average monthly THI, and mortality was associated with amount of fat per day in the liquid diet and morbidity.

Preweaned heifer management on US dairy operations: Part II. Factors associated with colostrum quality and passive transfer status of dairy heifer calves

Passive transfer of immunity is essential for the short- and long-term health of dairy calves. The objective of this study was to evaluate factors associated with colostrum quality and passive transfer status of US heifer calves. This study included 104 operations in 13 states that participated in the calf component of the National Animal Health Monitoring System's Dairy 2014 study. This 18-mo longitudinal study included 1,972 Holstein heifer calves from birth to weaning. Multivariable mixed linear regression models were selected using backward elimination model selection after univariate screening to determine which factors were associated with colostrum IgG and serum IgG concentrations. The mean colostrum IgG concentration was 74.4 g/L with 77.4% of colostrum samples having IgG concentrations >50 g/L. The final model for colostrum IgG included colostrum source and a categorized temperature-humidity index value (cTHI) for the month before calving. Mean colostrum IgG concentrations were highest for dams in third and higher lactations (84.7 g/L) and lowest for commercial colostrum replacers (40.3 g/L). Colostrum IgG concentrations were highest for cTHI ≥70 (72.6 g/L) and lowest for cTHI <40 (64.2 g/L). The mean serum IgG concentration was 21.6 g/L, with 73.3% of calves having serum IgG concentrations >15 g/L. The final model for serum IgG concentration included region, heat treatment of colostrum, colostrum source, timing to first feeding, volume of colostrum fed in the first 24 h, age of the calf at blood sampling, and colostrum IgG concentration. Mean serum IgG concentrations were highest for calves that received colostrum from first-lactation dams (25.7 g/L) and lowest for calves fed commercial colostrum replacer (16.6 g/L). Serum IgG concentrations were higher for calves fed heat-treated colostrum (24.4 g/L) than for calves fed untreated colostrum (20.5 g/L). Serum IgG concentration was positively associated with the volume of colostrum fed in the first 24 h and colostrum IgG concentration, and negatively associated with the number of hours from birth to colostrum feeding and age (days) at blood collection. Dairy producers should be encouraged to measure the quality of colostrum before administering it to calves and to measure serum IgG or a proxy such as serum total protein or Brix to evaluate passive immunity and colostrum management programs.

Preweaned heifer management on US dairy operations: Part I. Descriptive characteristics of preweaned heifer raising practices

The objective of this study was to describe preweaned dairy heifer calf management practices on dairy operations across the United States that were used to analyze factors associated with colostrum quality and passive transfer, Cryptosporidium and Giardia, morbidity and mortality, and average daily gain. This study included 104 dairy operations in 13 states that participated in the National Animal Health Monitoring System's Dairy 2014 calf component study. This 18-mo longitudinal study focused on dairy heifer calves from birth to weaning, and data were collected on 2,545 heifer calves. Descriptive statistics were generated regarding colostrum feeding, preweaning housing, milk feeding and consumption, growth, morbidity and mortality, and weaning practices. The majority of calves enrolled were Holsteins (89.4%). Over half the calves (63.2%) enrolled in the study received the majority of their colostrum via bottle; however, 22.1% of calves from 51.0% of operations received colostrum via suckling from their dams. For all calves, the mean time to the first colostrum feeding was 2.8 h, and the average amount of colostrum at the first feeding was 2.9 L, with 4.5 L provided in the first 24 h. The mean serum IgG of all calves was 21.7 g/L; however, 76.0% of operations had at least 1 calf with failure of passive transfer of immunity with a serum IgG below 10 g/L. The majority of calves in the study were housed individually (86.6%). Nonetheless, 20.2% of operations housed some calves in groups, representing 13.4% of all calves. Approximately one-half of the calves in the study (52.3%) were dehorned or disbudded during the preweaning period, with only 27.8% of these calves receiving analgesics or anesthetics during the procedure. Whole or waste milk was the liquid diet type fed to 40.1% of calves, and milk replacer was fed to 34.8% of calves. A combination of milk and milk replacer was fed to 25.1% of calves. Calves, on average, were fed 2.6 L per feeding and fed 2.6 times/d, resulting in a total of 5.6 L of liquid diet fed per day. The mean average daily gain for all calves enrolled in the study was 0.7 kg/d. Fecal samples were collected and almost all operations had at least 1 calf positive for Cryptosporidium (94.2%) or Giardia (99.0%), and 84.6% of operations had calves that tested positive for both Cryptosporidium and Giardia. Over one-third of calves (38.1%) had at least one morbidity event during the preweaning period and the mortality rate was 5.0%. The mean age at weaning was 65.7 d. This study provides an update on dairy heifer raising practices in the United States.

Identification and Characterization of Isolates of Pythium and Phytophthora spp. from Snap Beans with Cottony Leak

Cottony leak is an important disease of snap bean in Oklahoma and nearby states. Oomycete pathogens isolated from diseased pods collected from commercial fields and research plots consisted of both Pythium spp. (n = 131) and Phytophthora spp. (n = 46). Isolates were identified to species by morphological characteristics and by sequencing a portion of the internal transcribed spacer region of representative isolates. The most common Pythium spp. were Pythium ultimum var. ultimum; Pythium 'group HS', a self-sterile form of P. ultimum that produces hyphal swellings in lieu of sporangia (n = 74); and P. aphanidermatum (n = 50). Phytophthora spp. included Phytophthora drechsleri (n = 41) and P. nicotianae (n = 5). Nearly all of the isolates (95%) and all species were pathogenic on detached pods but Pythium ultimum var. ultimum and Pythium 'group HS' were most aggressive. Phytophthora drechsleri was most aggressive on seedlings, causing preemergence damping off and seed rot. Pythium ultimum var. ultimum, Pythium 'group HS', and P. aphanidermatum were intermediate in virulence to seedlings, causing root rot, stunting, and limited postemergence damping off. Phytophthora nicotianae and Pythium diclinum (n = 4) were not pathogenic on seedlings. Most (87%) isolates were sensitive to metalaxyl-M (concentration that caused a 50% reduction in mycelial growth [EC₅₀] < 1 μg/ml) and the rest were intermediate in sensitivity (EC₅₀ > 1 to < 100 μg/ml). Phytophthora drechsleri was the most sensitive species (EC₅₀ = 0.06 μg/ml) compared with Pythium aphanidermatum, which was least sensitive (EC₅₀ = 1.3 μg/ml). Cottony leak is a disease complex caused by several oomycete species that should include Phytophthora drechsleri, a newly reported pathogen of snap bean in the United States.

A simplified strategy for sensitive detection of Rose rosette virus compatible with three RT-PCR chemistries

Rose rosette disease is a disorder associated with infection by Rose rosette virus (RRV), a pathogen of roses that causes devastating effects on most garden cultivated varieties, and the wild invasive rose especially Rosa multiflora. Reliable and sensitive detection of this disease in early phases is needed to implement proper control measures. This study assesses a single primer-set based detection method for RRV and demonstrates its application in three different chemistries: Endpoint RT-PCR, TaqMan-quantitative RT-PCR (RT-qPCR) and SYBR Green RT-qPCR with High Resolution Melting analyses. A primer set (RRV2F/2R) was designed from consensus sequences of the nucleocapsid protein gene p3 located in the RNA 3 region of RRV. The specificity of primer set RRV2F/2R was validated in silico against published GenBank sequences and in-vitro against infected plant samples and an exclusivity panel of near-neighbor and other viruses that commonly infect Rosa spp. The developed assay is sensitive with a detection limit of 1fg from infected plant tissue. Thirty rose samples from 8 different states of the United States were tested using the developed methods. The developed methods are sensitive and reliable, and can be used by diagnostic laboratories for routine testing and disease management decisions.

In situ site-specific specimen preparation for atom probe tomography

Techniques for the rapid preparation of atom-probe samples extracted directly from a Si wafer are presented and discussed. A systematic mounting process to a standardized microtip array allows approximately 12 samples to be extracted from a near-surface region and mounted for subsequent focused-ion-beam sharpening in a short period of time, about 2h. In addition, site-specific annular mill extraction techniques are demonstrated that allow specific devices or structures to be removed from a Si wafer and analyzed in the atom-probe. The challenges presented by Ga-induced implantation and damage, particularly at a standard ion-beam accelerating voltage of 30 keV, are shown and discussed. A significant reduction in the extent of the damaged regions through the application of a low-energy "clean-up" ion beam is confirmed by atom-probe analysis of the damaged regions. The Ga+ penetration depth into {100} Si at 30 keV is approximately 40 nm. Clean-up with either a 5 or 2 keV beam reduces the depth of damaged Si to approximately 5 nm and <1 nm, respectively. Finally, a NiSi sample was extracted from a Si wafer, mounted to a microtip array, sharpened, cleaned up with a 5 keV beam and analyzed in the atom probe. The current results demonstrate that specific regions of interest can be accessed and preserved throughout the sample-preparation process and that this preparation method leads to high-quality atom probe analysis of such nano-structures.

Dietary-induced metabolic acidosis decreases bone mineral density in mature ovariectomized ewes

Dietary-induced metabolic acidosis (DIMA) may be a significant confounder in the development of osteoporosis. Diets that are acidifying are typically rich in proteins and grains and relatively poor in fruits and vegetables. Previous studies have not examined whether an interaction between estrogen depletion and DIMA have a compounded affect on bone mineral density loss. Sheep have been used successfully in previous studies to examine the interaction of bone turnover and ovariectomy. Therefore, the goal of this pilot study was to determine if bone mineral density (BMD) loss could be induced using DIMA in skeletally mature ovariectomized (OVX) ewes.

A phase II trial of temozolomide for patients with recurrent or progressive brain metastases

BACKGROUND

Treatment options for patients with recurrent brain metastases are extremely limited. This study was designed to determine the safety and efficacy of temozolomide in the treatment of recurrent or progressive brain metastases.

PATIENTS AND METHODS

Forty-one patients (11 men, 30 women) with a median KPS of 80 were treated with temozolomide 150 mg/m2/day (200 mg/m3/day if no prior chemotherapy) for 5 days; treatment cycles were repeated every 28 days. Primary tumor types included 22 non-small cell lung, 10 breast, three melanoma, two small cell lung, two rectal, one ovarian and one endometrial cancer.

RESULTS

There were five episodes of grade 3 thrombocytopenia and one grade 4 leukopenia. Significant non-hematologic toxicity possibly related to temozolomide included pneumonitis [21, constipation [1], and elevated liver enzymes [21. Thirty-four patients were assessed for radiographic response; two had a partial response, 15 stable disease and 17 progressed. Both objective responses were seen in patients with non-small cell lung cancer. Overall median survival was 6.6 months.

CONCLUSIONS

Single agent temozolomide achieved disease control (PR or SD) in 41% of patients with recurrent brain metastases from a variety of primary malignancies with minimal toxicity. Therefore, temozolomide may be a reasonable treatment option for some patients with recurrent brain metastases.

Outcome of transfusion of K:11 erythrocytes in a patient with anti-K11 antibody

BACKGROUND AND OBJECTIVES

The clinical significance of anti-K11 in red cell transfusion therapy is unknown. We report the outcome of transfusion of K:11 erythrocytes into a patient with a known anti-K11 antibody.

MATERIALS AND METHODS

The patient was monitored clinically following transfusion of 11 units of K:11 erythrocytes. A red cell survival study with K:11 erythrocytes and a monocyte monolayer assay (MMA) were performed.

RESULTS

No adverse clinical outcome was detected. The red cell survival study showed normal survival of K:11 erythrocytes, and the MMA showed no increase in reactive monocytes.

CONCLUSION

These findings suggest that K:11 red cells can safely be transfused to individuals with anti-K11 antibody.

Inhibition of human platelet function by sulfatides

Sulfatides are glycolipid constituents of human platelet cell membranes and have been shown to interact with platelet-binding proteins involved in hemostasis. Because little is known about the physiological role of sulfatides in platelet function, the effect of sulfatide on platelet adhesion, aggregation, release, and ristocetin-induced platelet agglutination (RIPA) was studied. These processes are inhibited when exogenous sulfatide is present in vitro. Inhibition of aggregation induced by collagen, thrombin, and ristocetin by sulfatide was dose dependent. Adenosine diphosphate-mediated adhesion and aggregation were not significantly affected by sulfatide, nor was serotonin- and epinephrine-mediated aggregation. Collagen mediate release of serotonin was reduced sulfatide. RIPA demonstrated dose-dependent inhibition in response to sulfatide. These results suggest that sulfatide may play a role in modulating platelet activation.

Long-term outcome of low-grade oligodendroglioma and mixed glioma

BACKGROUND

Low-grade oligodendrogliomas and mixed gliomas can be indolent and remain unchanged for years. Optimal timing and effectiveness of initial treatment is uncertain and therapy can be associated with toxicity.

METHODS

Retrospective review of patients diagnosed between 1979 and 1997 with low-grade oligodendroglioma or mixed glioma. Time to progression, survival, prognostic factors, and treatment toxicities were evaluated.

RESULTS

A total of 106 patients (77 oligodendroglioma, 29 mixed glioma) were identified; median age was 36.7 years. Initial presenting symptoms were seizures in 76 (72%) and headache in 11 (10%); tumor was diagnosed as an incidental finding in five patients. Tumor progression was diagnosed in 72 patients (68%). Overall median time to progression (MTTP) was 5.0 years (range 0.5 to 14.2). Median overall survival (OS) was 16.7 years. No prognostic factors reached statistical significance. MTTP and OS were not significantly affected by treatment. Of 62 patients who received radiation therapy, 9 (15%) developed radiation necrosis and 13 developed radiation therapy-related cognitive changes, requiring ventriculoperitoneal shunting in six. Significant myelosuppression was seen in 35 of 76 (46%) patients treated with chemotherapy.

CONCLUSIONS

Low-grade oligodendroglioma and mixed glioma have a long median overall survival. There were no apparent differences in either immediate versus deferred treatment or choice of initial therapy on disease-free or overall survival. Chemotherapy was associated with significant acute toxicity in almost one half of patients; radiation therapy produced late neurotoxicity in one third, justifying deferred treatment until clinically necessary.

Coexisting dysfibrinogenemia (gammaR275C) and factor V Leiden deficiency associated with thromboembolic disease (fibrinogen Cedar Rapids)

Fibrinogen Cedar Rapids is a heterozygous dysfibrinogenemia (gammaR275C) that was associated with thromboembolism during and following pregnancy in three second-generation family members who also were heterozygotic for factor V Leiden (V R506Q). Like other dysfibrinogenemias with substitutions at position 275 of the gamma-chain, fibrinogen Cedar Rapids is characterized by defective end-to-end intermolecular fibrinogen and fibrin 'D : D' associations, a fibrin network structure that is composed of thicker and more highly branched fibers, normal fibrin 'D: E' associations, and normal factor XIII-mediated crosslinking of fibrinogen and fibrin. In addition, Cedar Rapids fibrinogen and fibrin displayed delayed plasmin lysis rates. Compared with normal fibrinogen, platelet aggregation or platelet fibrinogen receptor clustering was defective in the presence of fibrinogen Cedar Rapids. Most subjects with gammaR275 mutations do not experience clinical thrombotic disorders, suggesting that the combination of a factor V Leiden defect and a gammaR275C dysfibrinogenemia predisposes to thromboembolic disease.

A method for proficiency testing of small peer groups in the College of American Pathologists Coagulation Surveys

OBJECTIVE

To develop a grading scheme for the proficiency testing of small peer groups of fewer than 10 members for the prothrombin time (PT) and activated partial thromboplastin time (APTT).

METHODS

A modified target value for small peer groups was derived based on the assumption that measurement variability in the PT and APTT is more greatly influenced by variations in reagents than in instruments. Criteria for grading were established by statistical simulation to achieve misclassification errors of less than 5% for both incorrectly passing and failing participants. College of American Pathologists Coagulation Survey data were analyzed to determine the number of additional laboratories graded using the proposed scheme, as well as the failure rates among participants in the small peer groups.

RESULTS

The modified target value for small peer groups is a weighted average between the mean of the peer group and the mean of all participants using the same reagent (reagent group). Peer groups with as few as 4 members can be graded provided that specific criteria are satisfied: there must be at least 5 peer groups for the same reagent, at least 3 of these 5 peer groups must have more than 3 members, and the coefficient of variation for the reagent group must be less than 10%. This proposed grading scheme decreased the number of ungraded laboratories by 44% to 46% for the PT and 42% to 55% for the APTT. The percentage of failing grades among participants in the small peer groups ranged from 1.3% to 4.1% for the PT and 1.4% to 7.2% for the APTT. These failure rates were 2.8- to 13.0-fold higher than the failure rates in large peer groups (P < or = .05).

CONCLUSIONS

The proposed small peer group grading scheme can improve the effectiveness of College of American Pathologists proficiency testing for the PT and APTT and may also be generally applicable to other test methods and analytes.

Fetal hemorrhage and platelet dysfunction in SLP-76-deficient mice

The adapter protein SLP-76 is expressed in T lymphocytes and hematopoietic cells of the myeloid lineage, and is known to be a substrate of the protein tyrosine kinases that are activated after ligation of the T-cell antigen receptor. Transient overexpression of SLP-76 in a T-cell line potentiates transcriptional activation after T-cell receptor ligation, while loss of SLP-76 expression abrogates several T-cell receptor-dependent signaling pathways. Mutant mice that lack SLP-76 manifest a severe block at an early stage of thymocyte development, implicating SLP-76 in signaling events that promote thymocyte maturation. While it is clear that SLP-76 plays a key role in development and activation of T lymphocytes, relatively little is understood regarding its role in transducing signals initiated after receptor ligation in other hematopoietic cell types. In this report, we describe fetal hemorrhage and perinatal mortality in SLP-76-deficient mice. Although megakaryocyte and platelet development proceeds normally in the absence of SLP-76, collagen-induced platelet aggregation and granule release is markedly impaired. Furthermore, treatment of SLP-76-deficient platelets with collagen fails to elicit tyrosine phosphorylation of phospholipase C-gamma2 (PLC-gamma2), suggesting that SLP-76 functions upstream of PLC-gamma2 activation. These data provide one potential mechanism for the fetal hemorrhage observed in SLP-76-deficient mice and reveal that SLP-76 expression is required for optimal receptor-mediated signal transduction in platelets as well as T lymphocytes.

Tracing the timing of human analysis of motion and chromatic signals from occipital to temporo-parieto-occipital cortex: a transcranial magnetic stimulation study

In human visual analysis, the initial processing of motion and chromatic signals may be mediated by feed-forward pathways from striate cortex to segregated areas of extrastriate cortex. The time-course of occipital to temporo-parieto-occipital motion processing was unknown, as was the selectivity of the effect of transcranial magnetic stimulation (TMS) on motion processing. TMS delivered over occipital cortex degraded the discrimination of motion-defined form (MDF) in a discrete time window beginning 100-120 ms from the onset of the visual stimulus. Bilateral focal TMS delivered over the temporo-parieto-occipital junction (TPO) disrupted the discrimination of MDF in a time window beginning 20-40 ms later than the effect of TMS delivered over occipital cortex. Bilateral focal TMS delivered over TPO also degraded the discrimination of CDF, motion direction, and color.

College of American Pathologists Conference XXXI on laboratory monitoring of anticoagulant therapy: laboratory monitoring of unfractionated heparin therapy

OBJECTIVE

To review the state of the art as reflected in the medical literature and the consensus opinion of recognized experts in the field regarding the laboratory monitoring of unfractionated heparin therapy.

DATA SOURCES, EXTRACTION AND SYNTHESIS

The authors made an extensive review of the literature. The draft manuscript was circulated to every participant in the consensus conference prior to the convening of the conference. Extensive discussion concerning all of the issues addressed in the manuscript as well as the resulting recommendations occurred. This information was then used to revise the manuscript into its final form.

CONCLUSIONS

The resulting manuscript has 23 specific recommendations regarding preanalytic, analytic, and postanalytic phases of monitoring and testing for complications related to unfractionated heparin therapy. This report contains detailed discussion of these recommendations and includes literature citations that support them. A number of issues for which consensus could not be reached are also discussed. A method is provided to assist laboratories, particularly small laboratories, in providing clinicians with an appropriate therapeutic range for the activated partial thromboplastin time, the most commonly used test in monitoring heparin therapy.

The Collaborative Hospital Transfusion Study: variations in use of autologous blood account for hospital differences in red cell use during primary hip and knee surgery

BACKGROUND

Red cell use in patients undergoing Diagnosis Related Group (DRG) 209 procedures (major joint and limb reconstruction procedures of the lower extremities) has been shown to have large, unexplained interhospital variations.

STUDY DESIGN AND METHODS

Abstracted records of 2590 consecutive DRG 209 patients at five university hospitals from January 1992 to December 1993 were stratified by procedure and preoperative blood deposit status. Patient characteristics and transfusion and in-hospital outcomes were compared across hospitals.

RESULTS

Blood use among patients who did not preoperatively deposit blood was similar across hospitals. Significant differences were found across hospitals for total hip replacement patients in the percentage of patients preoperatively depositing blood (59-80%), percentage of patients receiving transfusion(s) (51 to > 99%), the mean number of units collected per patient (1.6-2.9), and the mean number of unused autologous units per 100 patients (1-185). No significant differences were found in the percentage of those who deposited blood and then required allogeneic units. There was little variability in length of hospital stay or in last hematocrits. Findings were similar for total knee replacement patients.

CONCLUSIONS

Interhospital variations in red cell use for primary total hip and knee reconstruction are primarily due to hospital-specific differences in autologous blood collection and transfusion.

The specific hospital significantly affects red cell and component transfusion practice in coronary artery bypass graft surgery: a study of five hospitals

BACKGROUND

Interhospital differences in blood transfusion practice during coronary artery bypass graft (CABG) surgery have been noted, but the underlying issues have not been identified.

STUDY DESIGN AND METHODS

Records of 3217 consecutive CABG cases in five university teaching hospitals in 1992 and 1993 were stratified by hospital, type of revascularization conduit, patients' sex, and other factors. Statistical methods were used to compare patient characteristics, transfusion outcomes, and hospital outcomes.

RESULTS

Forward two-step logistic regression using patient likelihood of red cell transfusion factors in the first step and the specific hospital in the second step revealed a significant effect of hospital on the delta odds ratios for red cell transfusion. This finding was confirmed by analyses of a highly stratified subset of cases, males in diagnosis-related group 107 (primary cases of coronary bypass without coronary catheterization) who underwent revascularization with venous and internal mammary artery grafts, revealing variations among hospitals from 109 to 457 units of red cells transfused per hundred cases. Corresponding variations in transfusions of all blood components were from 324 to 1019 units by hospital. Variation in red cell transfusion practice among surgeons in the same hospital was not responsible for these interhospital differences.

CONCLUSION

The effect of the specific hospital on transfusion practice is attributed to institutional differences that, through reasons of training or hierarchy, become ingrained in hospitals.

Evaluation of a new protamine titration method to assay heparin in whole blood and plasma

When unfractionated heparin is used for therapeutic anticoagulation, the heparin effect must be monitored to avoid thrombotic or hemorrhagic complications. The ability of a factor Xa inhibition (XaI) assay was compared with that of a low-level heparin protamine titration (LLHPT) assay to measure the concentration of heparin after heparin was added in vitro to specimens of plasma and whole blood. Heparin effect on the activated partial thromboplastin time also was assessed in the same specimens. The XaI and LLHPT assays had comparable precision and provided linear results over a wide range of heparin concentrations. Both assays slightly underestimated the total amount of heparin added to the specimens. The most rapid test was the whole blood LLHPT assay; this test therefore may be useful for bedside monitoring of heparin. A significant disadvantage of the LLHPT assay was the large sample size required to perform it. These results provide in vitro evidence that the XaI and LLHPT assays can provide equally precise monitoring of heparin concentration.

Determinants of red cell, platelet, plasma, and cryoprecipitate transfusions during coronary artery bypass graft surgery: the Collaborative Hospital Transfusion Study

BACKGROUND

Very little is known about the determinants of blood transfusions in patients undergoing coronary artery bypass graft surgery.

STUDY DESIGN AND METHODS

To identify factors that influenced the transfusion of red cells, platelets, plasma, and cryoprecipitate, statistical methods were used to study 2476 consecutive diagnosis-related group 106 and 107 patients in five teaching hospitals who underwent coronary artery bypass surgery between January 1, 1992, and June 30, 1993.

RESULTS

The likelihood of red cell transfusion was significantly associated with 10 preoperative factors: 1) admission hematocrit, 2) the patient's age, 3) the patient's gender, 4) previous coronary artery bypass surgery, 5) active tobacco use, 6) catheterization during the same admission, 7) coagulation defects, 8) insulin-dependent diabetes with renal or circulatory manifestations, 9) first treatment of new episode of transmural myocardial infarction, and 10) severe clinical complications. Platelet and/or plasma transfusions were strongly associated with the dose of red cells transfused. Transfusion requirements and other in-hospital outcomes were associated with patient characteristics, surgical procedure (reoperation vs. primary procedure), and the conduits used for revascularization (venous graft only, venous and internal mammary artery graft, or internal mammary artery graft only). Blood resource use and donor exposures were evaluated with respect to the risk to patients of contracting hepatitis C virus and human immunodeficiency virus infections.

CONCLUSION

The classification of coronary artery bypass graft patients on the basis of attributes known preoperatively and by conduits used yields subsets of patients with distinctly different transfusion requirements and in-hospital outcomes.

Low interinstrument variability of the international normalized ratio with the coagamate X2/Simplastin excel system

Minimizing the interlaboratory variability of the International Normalized Ratio (INR) for patients receiving coumarin therapy will require local laboratory calibration of individual coagulation instrument/reagent systems. However, some laboratories possess multiple coagulation instruments of the same model, and it is unclear if each instrument would require separate calibration. To address this question, a controlled study was performed that examined the interinstrument variability of the INR on three separate Coagamate X2 coagulometers (Organon Teknika, Durham, NC) using the Simplastin Excel reagent (Organon Teknika) (International Sensitivity Index = 2.14). The interinstrument coefficient of variation (CV) of the INR among the three instruments was 3.4% and 3.5% for patient control plasmas (n = 20) and coumarin plasmas (n = 40, INR range 1.5-4.6), respectively. The number of discordant INRs between paired instruments (one INR within and one INR out of the therapeutic range, plus a difference of at lest 0.4 INR units) was very low (0%). The interinstrument INR CVs for three commercial quality control plasmas were 2.6% (INR = 0.92), 4.1% (INR = 2.1), and 6.3% (INR = 4.5), and correlated well with the low CVs for patient samples. This study showed that the Coagamate X2/Simplastin Excel system is capable of very low interinstrument INR variability, and surpasses the interlaboratory CVs reported in the literature. Formal calibration of a single instrument may be adequate for laboratories possessing multiple instruments of the same model.

Brightness of uniform stabilized fields

Brightness of uniform fields during normal and stabilized viewing was determined as a function of adapting luminance, field size, and luminance gradient of the edges of the adapting field. In one set of experiments, it was found that, over a range of adapting luminances from 6 to 9600 td, a uniformly-illuminated 7.5 deg hemifield appeared about 1 log unit brighter in normal viewing than when it was retinally-stabilized. In the second set of experiments, it was found that the loss of brightness due to stabilized viewing was significantly greater for large fields with raised cosine edges than for small fields with step edges. Both sets of results can be accounted for by a two-stage model of light adaptation previously proposed to account for the fading time of stabilized images.

Determination of dissociation constant and concentration of an anti-DNA antibody by using the light-addressable potentiometric sensor

The most sensitive assay possible is desired for quantitation of total DNA and DNA probe binding. To reduce background signal, which may reduce assay sensitivity, it is desirable to employ low antibody concentrations. This requires the use of a specific antibody with a high affinity for DNA.

Picogram detection levels of asialofetuin via the carbohydrate moieties using the light addressable potentiometric sensor

Fetal calf serum asialofetuin was assayed in the sandwich format using biotinylated and fluoresceinated ricin toxin (B-RCA and F-RCA). The sandwiched species was captured on a biotin-BSA coated nitrocellulose membrane with streptavidin. Anti-fluorescein antibody-urease conjugate was bound to the complex, and detected and quantitated under microvolume conditions using the light addressable potentiometric sensor. As little as 250 pg of asialofetuin was detectable whereas fetuin gave no response at conditions as high as 32 ng. Using a competitive inhibition assay, we established that the binding constant for the asialofetuin-ricin complex was 3.6 x 10(8) M-1. This is in good agreement with data published using glycopeptides derived from asialofetuin, and RCA and the ricin agglutinin, RCA-120.

Analysis of changes in coagulation factors after postoperative blood loss in burn and non-burn patients

A prospective study of the postoperative kinetics of coagulation factors was undertaken in 23 burn patients and in six non-burn patients. All procedures resulted in a large volume blood loss. Fibrinogen, platelets and factors V, VIII and IX were measured serially. Burn patients returned all parameters to preoperative levels by 48 h postoperation, while non-burn patients showed a slower rate of return of platelets and factor V. This study suggests that burn patients may safely undergo re-operation at 48 h intervals for successive wound debridements if clinically necessary.

Packed red cells in acute blood loss: dilutional coagulopathy as a cause of surgical bleeding

The purpose of this study was: 1) to define coagulation abnormalities in patients who receive red cell concentrates rather than whole blood for large volume blood loss (greater than 0.5 blood volume); and 2) to determine when coagulation abnormalities lead to increased bleeding in the massively transfused surgical patient. We studied 32 ASA physical status I or II patients (mean age 15.6 +/- 2.3 yr) who lost more than 50% of their blood volume during elective posterior spinal stabilization. Crystalloid solutions and packed red cell concentrates were used to replace blood and fluid losses. Invasive hemodynamic measures, urinary output, and serial hematocrit determinations were used to help maintain a constant intravascular volume and confirm the estimates of blood loss. The quality of hemostasis was assessed during operation. In 15 of the 32 patients, surgical hemostasis remained effective throughout posterior spinal fusion. A coagulation profile (prothrombin time [PT] and activated partial thromboplastin time [aPTT], platelet count, and fibrinogen) was measured at the conclusion of operation in these patients. In 17 patients, increased surgical bleeding as a result of decreased clot formation and increased bleeding from the wound was present. In these 17 patients at the time increased bleeding was diagnosed, hemostatic tests (PT, aPTT, fibrinogen, platelet count, and coagulation factor assays V, VIII, and IX) were obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolated right atrial tamponade after open heart surgery: role of echocardiography in diagnosis and management

Ten patients with isolated right atrial tamponade complicating open heart surgery were identified over a 3.5-year period at three institutions. Clinical manifestations varied but were typically those of decreased perfusion with elevated central venous pressure. Hemodynamically these patients had systemic hypotension and tachycardia with elevated central venous pressure but without elevation of pulmonary artery or pulmonary artery wedge pressures. The correct diagnosis in each case was established by echocardiography; 7 via the transthoracic and 3 via the transesophageal approach. The typical echocardiographic feature was an extrinsic extracardiac mass compressing the atrium. Doppler findings included high flow velocities through the right atria, and color flow demonstrated narrow color jets through compressed, slit-like right atria. Surgical exploration confirmed these findings in each case. We conclude that the combination of clinical awareness and appropriate hemodynamic evaluation can alert the physician to the possibility of isolated right atrial hematoma causing decreased perfusion and/or shock following open heart surgery. Echocardiography using either the transthoracic or transesophageal approach can establish the diagnosis and lead to timely surgical intervention.

Cost-effective health information systems: user-driven internal development at the University of Iowa

GOALS

The Information Network For Online Retrieval & Medical Management (INFORMM), health information system (HIS) for the University of Iowa Hospitals and Clinics (UIHC), was analyzed with regard to development of a Computer-Based Patient Record (CBPR) in a cost-effective manner. The analysis: i) profiles INFORMM system functionality; ii) displays INFORMM use and satisfaction among physicians, nurses, and other hospital employees; iii) characterizes dynamics affecting INFORMM growth; and iv) evaluates the cost of a system of internal-development of software.

DATA SOURCES

INFORMM utilization for 1989, 1994, and 1995; service requests from users for the years 1985, 1990, and 1994; 1994 MECON-PEERx data; gap analysis user survey conducted by an independent consulting firm.

MAIN RESULTS

1) Physician use has been dominated by a single function: retrieval of laboratory results. 2) Nurse use of the system was more diverse. A recent surge of nurse and physician use resulted from the introduction of online documentation of nursing care. 3) Overall use has been predominantly by non-clinician users, no one function dominating their pattern of use. 4) User service requests were predominantly from the non-clinician group of users. Requests from non-physician groups have been coordinated by a limited number of representatives of those groups, unlike requests from physicians. 5) The UIHC HIS ranked high in user satisfaction. 6) The overall cost of the UIHC HIS system is relatively low as a percentage of the gross operating budget or as a ratio to the volume of patient activities in this medical center.

CONCLUSIONS

Internal development of INFORMM has been a cost-effective solution to the information demands of nursing staff and other users. INFORMM system composition reflects the quantity and organization of user requests. Satisfying the needs of physicians requires a change in the manner in which physician needs are assessed.

Adaptation with a stabilized retinal image: effect of luminance and contrast

The addition of a uniform increment of luminance (L) to a faded retinally-stabilized target results in the subjective reappearance of the image with contrast opposite to that of the target. This phenomenon, called apparent phase reversal (APR), reveals a nonlinear gain mechanism in the adaptation process. The magnitude of the threshold increment to elicit APR (Lapr) is a measure of the state of stabilized adaptation. In the experiments reported here, Lapr was studied as a function of background luminance (Lo) and contrast (m) of the adapting stimulus. It was found that Lapr increases with increasing Lo, but does not depend on m. The data are analyzed within the context of a previously proposed model of stabilized image fading consisting of a multiplicative inverse gain followed by a subtractive process. It was found that the addition of a contrast processing stage was required to account for the relationship between Lapr and m.

Monoclonal antibodies to platelet glycoproteins Ib and IIb/IIIa inhibit adhesion of platelets to purified solid-phase von Willebrand factor

Platelet membrane glycoproteins Ib (GPIb) and IIb/IIIa (GPIIb/IIIa) bind soluble von Willebrand factor (vWf) after stimulation with ristocetin (GPIb) or with thrombin or ADP (GPIIb/IIIa). In fluid-phase, vWf does not bind to these platelet receptors without stimulation. In contrast, platelets adhere to solid-phase vWf without stimulation by ristocetin, adenosine diphosphate (ADP), or thrombin, and adhesion increases after stimulation by these agonists. The effect of monoclonal antibodies specific for GPIb (6D1) and GPIIb/IIIa (10E5 and HP1-1D) on platelet adhesion to solid-phase vWF was studied. Adhesion of radiolabeled, washed platelets (with washed red blood cells) aspirated at a constant wall shear rate of 1000 sec-1 through glass capillary tubes coated with purified human vWf was quantified. Unstimulated platelet adhesion was decreased 80% to 90% by blocking either the GPIb site or the GPIIb/IIIa site with 6D1 or 10E5, respectively, or with 6D1 and 10E5 together. Adhesion was not reduced significantly by HP1-1D (anti-GPIIb/IIIa). After stimulation with ADP or thrombin, the platelet adhesion was reduced by prior incubation with saturating concentrations of either 6D1 (61% reduction) or 10E5 (80% reduction), as well as with both 6D1 and 10E5 (80% reduction). After stimulation with ristocetin, the adhesion was reduced with either 6D1 (90% reduction) or 10E5 (90% reduction) or both 6D1 and 10E5 (90% reduction). Prior incubation with HP1-1D had minimal effect on platelet adhesion to vWF after stimulation with thrombin, ADP, or ristocetin.(ABSTRACT TRUNCATED AT 250 WORDS)

The reliability of manufacturer-determined, instrument-specific international sensitivity index values for calculating the international normalized ratio

Some thromboplastin manufacturers are currently supplying the instrument-specific international sensitivity index (ISI) values of their reagents, allowing clinical laboratories to calculate instrument-specific international normalized ratio (INR) values on plasma samples from patients receiving coumarin therapy. However, the assumption that systematic interinstrument variability in the INR would be eliminated if manufacturer-determined ISI values were used remains unsubstantiated. This assumption was evaluated by comparing INR values obtained on one instrument that measures a mechanical endpoint (fibrometer) with one that measures a photo-optical endpoint (MLA-700). Three thromboplastin reagents with instrument-specific ISI values supplied by the manufacturer (ISI range, 1.23-2.79) were used. For two of three reagents, the fibrometer INR values were significantly higher than the MLA-700 INR values (P < .01). Analysis of log prothrombin time ratio plots showed that this systematic variability was caused by inaccurate manufacturer ISI values. Of clinical significance is that the inaccurate ISI values produced a high number of discordant INR values between these two instruments (> 47% of plasma samples had one INR value within and one out of the recommended therapeutic range). The implication of these findings for laboratory monitoring of oral anticoagulation is discussed.

Antibody-antigen binding constants determined in solution-phase with the threshold membrane-capture system: binding constants for anti-fluorescein, anti-saxitoxin, and anti-ricin antibodies

Affinities of various monoclonal and polyclonal antibodies for fluorescein-containing antigens, saxitoxin and ricin, were determined by using a light addressable potentiometric sensor-based system (Threshold). The dissociation constants, determined from Scatchard plots, ranged from 2 x 10(-7) to approximately 3 x 10(-12) M. Dissociation constants for fluorescein and saxitoxin were compared with values determined by independent means. This technique was found to be quick, simple, reproducible, and accurate.

Immunochemical detection using the light-addressable potentiometric sensor

Rapid, sensitive and flexible assay systems are needed for immunoassays, receptor-ligand binding studies and DNA probe assays. Filtration capture and sensor detection offer several advantages to these areas. Although dependent on the affinity of the specific binders employed, the sensitivity of these techniques can be in the order of 10(-12) M, and total assay time can be less than 15 minutes.

Mechanisms of hemostasis. Effect on intracerebral hemorrhage

Aspects of the mechanisms of hemostasis are reviewed with particular emphasis on the assembly of enzyme complexes on the membranes of cells. The way this membrane fixation of reactions accelerates coagulation, inhibition, and fibrinolytic systems is discussed. The complex nature of the hemostatic system and the multiple complications of its abnormalities present a difficult problem for the neurologist and neurosurgeon managing the patient with intracerebral hemorrhage. This is a situation in which close consultation and collaboration among the neurological and hematologic specialists are imperative to achieve the most favorable outcome for the patient with this life-threatening situation.

Cytokine and complement levels in patients undergoing cardiopulmonary bypass

Patients undergoing cardiopulmonary bypass are known to develop whole body inflammation that often results in a characteristic syndrome early postoperatively. This phenomenon has been attributed to complement activation caused by exposure of blood to the foreign surfaces of the cardiopulmonary bypass circuit. It has been unknown if cytokines are involved. Plasma levels of complement activation products (C3a, C4a, C5a, and C5b-9), interleukins (IL-1 beta, IL-2, IL-4, and IL-6), and tumor necrosis factor-alpha were measured at multiple time points before, during, and after cardiopulmonary bypass in 29 patients. No significant increase over preinduction levels was seen in the cytokines except for IL-6, which was significantly increased during cardiopulmonary bypass (p < 0.001), reaching a maximum 3 hours after cardiopulmonary bypass. C3a, C4a, and C5b-9 levels were significantly elevated during cardiopulmonary bypass (p < 0.001), with maximum C5b-9 levels preceding the IL-6 elevation. Heparin coating of the cardiopulmonary bypass circuit was not demonstrated to have an effect on activation of complement or cytokine production. There was no statistically significant correlation among hemodynamic variables or pulmonary function and complement, interleukin, or tumor necrosis factor-alpha levels. These results confirm the presence of complement activation and demonstrate the production of IL-6 after the generation of C5b-9 in patients undergoing cardiopulmonary bypass. IL-6 may contribute to adverse systemic reactions associated with cardiopulmonary bypass.

Endoscopic carpal tunnel release: a comparison of two techniques with open release

Proponents of endoscopic carpal tunnel release claim less pain and scar tenderness, quicker recovery of strength, and earlier return to work and daily activities over open methods to release the transverse carpal ligament. This single-center prospective study is the first to compare three different treatment methods: standard open release, a single-portal endoscopic technique (Agee), and a two-portal endoscopic technique (Chow). Two hundred eleven releases in 163 patients were evaluated by clinical outcomes questionnaire and objective testing over a 6-month follow-up period. There was no difference in resolution of paresthesias or nocturnal pain between treatment methods. Patients treated with open release reported more thumb weakness and pain with activities of daily living after surgery. Endoscopically treated patients achieved faster recovery of grip and pinch strength and wrist range of motion. Patients treated endoscopically had less mid-palm tenderness than did patients treated via the open technique, and Agee patients had less distal palmar tenderness than did patients treated via other methods. Overall, and in the workers' compensation group, patients treated endoscopically returned to work sooner. In the non-workers' compensation group, Agree patients returned to work sooner than did patients treated via the other two methods.

Fading time of retinally-stabilized images as a function of background luminance and target width

Fading time of a retinally-stabilized difference-of-Gaussian (DOG) stimulus depends on the background luminance, contrast and spatial frequency content of the stimulus. A model of the visual system including a nonlinear multiplicative, non-local and fast process followed by a linear subtractive, local and slower process accounts for these effects. Analysis of the fading time data allows us to estimate the spatiotemporal characteristics of the proposed adaptation processes. The model is consistent with recent models of normal light adaptation from the probe-flash paradigm.

Glycosphingolipid inhibition of the adhesion of thrombin-activated platelets to surfaces is potentiated by albumin

Previous studies have shown that exogenous glycosphingolipids (GSLs) inhibit the adhesion of thrombin-activated platelets (TAP) to polystyrene plates coated with various RGD-ligands (where RGD is the peptide sequence Arg-Gly-Asp), suggesting that GSLs can modulate the platelet integrin receptor glycoprotein IIb-IIIa. However, albumin was always used as a plastic surface-blocking agent in these studies. In order to evaluate the role of albumin in these experiments, we studied the effect of various GSLs and albumin on the interaction between TAP and hydrophobic surfaces in a solid-phase assay using indium-111-labelled platelets and polystyrene plates. TAP (10(8) platelets/ml) adhered to polystyrene (half-saturation time 40 +/- 3 min) with a maximal adhesion density of 56 +/- 1 x 10(3) platelets/mm2. Platelet adhesion was only slightly affected (< 11% inhibition) by immobilized bovine serum albumin, immobilized mixed bovine brain gangliosides (MBG) or fluid-phase MBG. In contrast, fluid-phase MBG was an effective inhibitor of platelet adhesion to polystyrene (> 46% inhibition), but only after albumin was first immobilized to the plate. Covering albumin-coated polystyrene with MBG, followed by washing, was as effective as fluid-phase MBG at inhibiting platelet adhesion, thus indicating that a ganglioside-albumin interaction at the polystyrene surface was responsible for effective inhibition. When purified GSLs were substituted for MBG, it was found that all those tested (GT1b, GD1a, GM1, asialo GM1 and globoside) had similar inhibitory activity.

Torsion of the gallbladder. A review of four cases

Four cases of torsion of the gallbladder have been gathered from this area. Three were admitted to our local hospitals and the fourth case occurred in the Veteran's Hospital in Fayetteville. The average age of these four cases was 85, and all patients were very thin. Three patients were female and one was male. One patient died following surgery. This patient had sought help rather late, and died of cardiopulmonary complications. This entity is rare, and only scattered cases are found in the literature. Biliary calculi are found in approximately 50% of the cases. The exact etiology of the torsion is unknown. A redundant mesentery is always present, and kyphosis is frequent. Our patients were all thin. Botha has postulated that vigorous peristalsis in the neighboring viscera or sudden body movement may be responsible. The diagnosis is rarely made preoperatively, but if surgery is not done, death will probably ensue. Later reports have indicated that sonography and abdominal CT scanning might prove helpful in establishing a diagnosis.

Effect of varying fibrinogen and hematocrit concentrations on magnetic resonance relaxation times of thrombus

OBJECTIVES

The authors assessed the effects of varying one extracellular component (fibrinogen concentration) and one cellular component (hematocrit) on magnetic resonance (MR) T1 and T2 relaxation times of in vitro blood clots.

METHODS

Blood from six male subjects was collected into sodium citrate anticoagulant (3.8%) and the whole blood was separated into platelet-rich plasma and packed erythrocytes. Subsequently, in vitro blood clots were made from varying concentrations of fibrinogen (1, 10, and 100 microM) in Tyrode's solution and washed, packed erythrocytes (hematocrit levels: 0%, 10%, 40%, and 80%). T1 and T2 measurements were completed at 20 MHz within 8 hours of initiating clotting.

RESULTS

Significant shortening of MR relaxation times occurred with increasing fibrinogen concentration for hematocrit values of 0% and 10%. Extracellular fibrinogen concentration did not contribute significantly to variation in relaxation times at hematocrit values of 40% and 80%. For any given fibrinogen level, significant shortening occurred in T1 and T2 values for each successive increase in hematocrit values.

CONCLUSIONS

Both extracellular (fibrinogen) and cellular (erythrocyte concentration) factors are significant determinants of thrombus T1 and T2 relaxation times.