Structural polymorphism of glycophorins demonstrated by immunoblotting techniques

We have explored the polymorphism of the glycophorin system in the human erythrocyte membrane using the immunoblotting techniques and examining 52 individuals selected without prior bias as to their serologic state and ten documented serologic variants of M, N, S, s blood group system. Polyclonal antisera to alpha glycophorin and to alpha glycophorin CNBr carboxyl terminal fragment C (residues 82-131) and M and N specific monoclonal antibodies (MoAbs) were used. The first two reagents detect specific regions of the alpha glycophorin molecule and all electrophoretically resolved species of glycophorins immunologically related to alpha and delta glycophorins (delta glycophorin, [alpha-delta] hybrids and other glycophorins with an alteration in the carboxyl terminal segment); the M and N MoAbs identified the glycophorin species containing or lacking the M or N determinant in the amino terminal octapeptide structures. We find that immunoblotting confirmed in all cases the serologically determined phenotype; we also find that polymorphic forms of the glycophorin system are relatively infrequent; immunoblotting, independent from serologic testing, was capable of detecting five mutants, two most likely S-s-U-phenotypes; a new glycophorin species was detected in normal red cells with both antiglycophorin and antipeptide C sera, which is not evident with MoAbs; immunoblots of known glycophorin variants (En(a-), U-, Mg, Mi I, II, III, V, and Sta) confirmed but also extended our knowledge of the abnormal glycophorins involved; and the He+ and Wrb(-) cells showed normal patterns.     

Hemodynamics during liver transplantation: the interactions between cardiac output and portal venous and hepatic arterial flows.

Liver blood flow and systemic hemodynamics were measured intraoperatively in 34 patients after liver transplantation. Ultrasound transit-time flow probes measured hepatic arterial and portal venous flow over 10 to 75 min 1 to 3 hr after reperfusion. Cardiac output was measured by thermodilution. Mean cardiac output was 9.5 +/- 2.8 L/min; the mean total liver blood flow of 2,091 +/- 932 ml/min was 23% +/- 11% of cardiac output. Mean portal flow of 1,808 +/- 929 ml/min was disproportionately high at 85% +/- 10% of total liver blood flow. Correlation analysis showed a significant (p less than 0.01; r = 0.42) correlation between cardiac output and portal venous flow and a trend toward negative correlation (p = 0.087) between cardiac output and hepatic arterial flow. These data show that increased flow in the newly transplanted liver is predominantly portal venous flow and is associated with high cardiac output and reduced hepatic arterial flow. In the last 13 patients studied, portal flow was reduced by 50% and the hepatic artery response was measured. We saw a significant (p less than 0.05) increase in hepatic artery flow from 322 +/- 228 to 419 +/- 271 ml/min, indicating an intact hepatic arterial buffer response. The hepatic artery response also showed that it is a reversible rather than a fixed resistance that contributes to the low hepatic artery flow in these patients.     

Characterization of the DialGuard device for endotoxin removal in hemodialysis

Bacterial pyrogens, capable of penetrating dialyzer membranes, are responsible for a systemic inflammatory reaction in hemodialysis patients. Dialyzer reuse, involving rinsing of the dialyzer with pyrogen-containing water, may exacerbate this situation. Studies of the mechanism of action of endotoxin suggest that it irreversibly damages the vascular endothelium. The novel endotoxin removal method described here, is based on affinity-binding of endotoxin by the adsorbent ClarEtox, a USP Class VI-certified resin that is the active component of the medical device DialGuard. Under standard hemodialysis operating conditions, challenge of DialGuard with Pseudomonas maltophilia supernatant-spiked dialysate, containing 35-193 EU/ml endotoxin, resulted in endotoxin levels below 0.05 EU/ml in the treated dialysate. DialGuard was able to decrease endotoxin concentrations in the dialysate from a range of 2.39-8.49 to <0.005 EU/ml. DialGuard supports high fluid velocities at low back pressures and can be sanitized using the heat sanitization cycle of hemodialysis machines. DialGuard offers a simple, user-friendly way to reduce the concentration of endotoxin in dialysate and water for dialysis at a low cost.     

Bleeding-avoidance strategies and outcomes in patients ≥80 years of age with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention (from the NCDR CathPCI Registry)

The purpose of our study was to evaluate the use of bleeding-avoidance strategies (BAS) and risk-adjusted bleeding over time in patients ≥80 years of age undergoing primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction. We analyzed data from the CathPCI Registry from July 1, 2006 through June 30, 2009. Patients were included if they were ≥80 years old, presented with ST-segment elevation myocardial infarction, and underwent primary PCI. We evaluated trends in use of BAS (direct thrombin inhibitors, vascular closure devices, and radial access) and risk-adjusted bleeding over time. Of 10,469 patients ≥80 years old undergoing primary PCI, 1,002, (9.6%) developed a bleeding complication. Use of direct thrombin inhibitors and vascular closure devices increased over time (12.8% to 24.9% and 29.2% to 32.7%, p <0.01 and <0.05 for trends, respectively). Radial access was extremely uncommon (<1%) and did not change over the course of the study. In multivariable analyses, use of BAS was associated with lower bleeding. However, over the course of the study period, overall risk-adjusted bleeding did not decrease significantly (9.9% to 9.4%, p = 0.14 for trend). In conclusion, patients ≥80 years old undergoing primary PCI are at high risk of bleeding, and despite significant increases in use of BAS, the overall rate of bleeding complications remains high.     

Locating the Sural Nerve during Calcaneal (Achilles) Tendon Repair with Confidence: A Cadaveric Study with Clinical Applications

The sural nerve is at risk of iatrogenic injury even during minimally invasive operative procedures to repair the calcaneal (Achilles) tendon. Through 107 cadaveric leg dissections, the data derived from the present study was used to develop a regression equation that will enable surgeons to estimate the intersection point at which the sural nerve crosses the lateral border of the Achilles tendon, an important surgical landmark. In most cases, the sural nerve crossed the lateral border of the Achilles tendon 8 to 10 cm proximal to the superior border of the calcaneal tuberosity. By simply measuring the leg length of the patient (from the base of the heel to the flexor crease of the popliteal fossa), surgeons can approximate the location of this intersection point with an interval length of 0.68 to 1.80 cm, with 90% confidence, or 0.82 to 2.15 cm, with 95% confidence. For example, for a patient with a lower leg length of 47.0 cm, the mean measurement in the present study, a surgeon can be 90% confident that the sural nerve will cross the lateral border of the Achilles tendon 8.28 to 8.96 cm (interval width of 0.68 cm) proximal to the calcaneal tuberosity. Currently, ultrasound and clinical techniques have been implemented to approximate the location of the sural nerve. The results of the present study offer surgeons another method, that is less intensive, to locate reliably and subsequently avoid damage to the sural nerve during calcaneal (Achilles) tendon repair and other procedures of the posterolateral leg and ankle.     

Two-temperature PCR and heteroduplex detection: application to rapid cystic fibrosis screening.

We describe a rapid two-temperature PCR protocol for amplification of genomic DNA applied to the region of the most common mutation (delta F508) of the cystic fibrosis gene. Amplification products are detected as homo- or heteroduplexes on polyacrylamide gels as previously described. Data using two-temperature PCR show complete concordance with allele-specific hybridization after classical three-temperature PCR in 105 normal, carrier and affected individuals. Clinical application is demonstrated in a family which was uninformative by traditional RFLP linkage analysis. Two-temperature PCR may offer advantages of speed and specificity over three-temperature PCR in many clinical and research applications.     

Paracetamol is an effective drug to use for pain following oral surgery

DATA SOURCE: Studies were identified using the Cochrane trials registers of the Oral Health Group and of the Pain, Palliative and Supportive Care Group, along with the Cochrane Central Register of Controlled Trials, Medline, Embase and the Current Controlled Trials Register. Handsearching included several dental journals as well as the bibliographies of relevant clinical trials and review articles for studies outside the journals searched by hand. Authors of the randomised controlled trials (RCT) identified and manufacturers of analgesic pharmaceuticals were contacted in an attempt to identify unpublished or ongoing RCT. No language restriction was applied. STUDY SELECTION: Randomised, parallel-group, placebo-controlled, double-blind clinical trials of paracetamol (acetaminophen) for acute pain following third molar surgery were included. DATA EXTRACTION AND SYNTHESIS: All trials identified were scanned independently and in duplicate by two review authors. Any disagreements were resolved by discussion or, if necessary, a third review author was consulted. The proportion of patients who recorded at least 50% pain relief was calculated for both paracetamol and placebo. The number of patients experiencing adverse events, and/ or the total number of adverse events reported were analysed. RESULTS: Twenty-one trials met the inclusion criteria. A total of 2048 people were initially enrolled in the trials (1148 took paracetamol and 892 the placebo) and of these 1968 (96%) were included in the meta-analysis (1133 took paracetamol, and 835 the placebo). Paracetamol provided a statistically significant benefit when compared with placebo for pain relief and for pain intensity at both 4 and 6 h. Most studies were found to have moderate risk of bias, with poorly reported allocation concealment being the main problem. The risk ratio for pain relief at 4 h was 2.85 (95% confidence interval, 1.89-4.29), and at 6 h was 3.32 (95% confidence interval, 1.88-5.87). A statistically significant benefit was also found between doses of <1000 mg and of 1000 mg, the higher dose giving greater benefit for pain relief and intensity at both timepoints. There was no statistically significant difference between the number of patients who reported adverse events: this was 19% in the paracetamol group and 16% in the placebo group. CONCLUSIONS: Paracetamol is an effective drug to use for postoperative pain following oral surgery, and the reporting of adverse events shows it to be a safe drug: the number-needed-to-treat (NNT) to benefit is three for 1000 mg of paracetamol at 6 h and the NNT to harm is 33. It is most effective at a 1000 mg dose, and can be taken at 6-hourly intervals without compromising safety. It could be considered more readily by dentist and patients both as a first-choice analgesic, or to be taken alternately with other analgesics such as nonsteroidal anti-inflammatory drugs.