Occupational risk of hepatitis C virus infection to dental health care staff: an update

In this review, we develop four topics on the relationship between blood transfusion and cancer. First, the rationale for not allowing blood donations from patients with infiltrating tumors is presented. Second, the different possibilities for autotransfusions in cancer patients are discussed. Predeposited autotransfusions are rarely possible in these patients, in addition to the high cost. The usefulness of another method, intraoperative autologous transfusion with blood saved from the surgical field, is not well established. Our third topic concerns the effect of transfusion on cancer induction. In some cases, the risk of cancer is higher after allogenic transfusion resulting from a mechanism involving alterations of the immune function. Finally, the relationship between transfusion and cancer recurrence is controversial. In spite of numerous studies attempting to elucidate this relationship, no final conclusion can be drawn at the present time. What is sure, is that patients requiring blood transfusion have a higher risk of recurrence than patients who do not need transfusion.     

Respiratory muscle work compromises leg blood flow during maximal exercise

We hypothesized that during exercise at maximal O2 consumption (VO2max), high demand for respiratory muscle blood flow (Q) would elicit locomotor muscle vasoconstriction and compromise limb Q. Seven male cyclists (VO2max 64 +/- 6 ml.kg-1.min-1) each completed 14 exercise bouts of 2.5-min duration at VO2max on a cycle ergometer during two testing sessions. Inspiratory muscle work was either 1) reduced via a proportional-assist ventilator, 2) increased via graded resistive loads, or 3) was not manipulated (control). Arterial (brachial) and venous (femoral) blood samples, arterial blood pressure, leg Q (Qlegs; thermodilution), esophageal pressure, and O2 consumption (VO2) were measured. Within each subject and across all subjects, at constant maximal work rate, significant correlations existed (r = 0.74-0.90; P < 0.05) between work of breathing (Wb) and Qlegs (inverse), leg vascular resistance (LVR), and leg VO2 (VO2legs; inverse), and between LVR and norepinephrine spillover. Mean arterial pressure did not change with changes in Wb nor did tidal volume or minute ventilation. For a +/-50% change from control in Wb, Qlegs changed 2 l/min or 11% of control, LVR changed 13% of control, and O2 extraction did not change; thus VO2legs changed 0.4 l/min or 10% of control. Total VO2max was unchanged with loading but fell 9.3% with unloading; thus VO2legs as a percentage of total VO2max was 81% in control, increased to 89% with respiratory muscle unloading, and decreased to 71% with respiratory muscle loading. We conclude that Wb normally incurred during maximal exercise causes vasoconstriction in locomotor muscles and compromises locomotor muscle perfusion and VO2.     

Importance of recording lead V1 in the seventh right intercostal space in diagnosing corpulmonale

Right-sided chest leads V1 to V6R were recorded in the 4th to 7th intercostal spaces in 25 cases of corpulmonale secondary to chronic obstructive pulmonary disease and in an equal number of age-matched controls. Results were compared with findings in the conventional electrocardiogram. Chest leads recorded in the seventh right intercostal space along the right sternal border could detect 24% of cases of corpulmonale that were missed by conventional leads.     

Use of REMEDi HS in emergency toxicology for a rapid estimate of drug concentrations in urine, serum, and gastric samples

The REMEDi HS is a broad spectrum drug identification system, designed for emergency toxicology screening and forensic applications. The total analysis time is about 20 min. The current library has 555 drugs and metabolites. The system has a software routine that uses an internal standard (IS) to perform quantitative analysis for target compounds when calibrators are available; further, response factors (RF) are supplied for a rapid estimate of drug concentrations when calibrators are unavailable. In the present study, The concentrations of six drugs (bromisovalum, ephedrine, hydroxyzine, diphenhydramine, ranitidine, and lidocaine) and a metabolite of lidocaine (glycinexylidide) were determined using both methods. The slopes of the regression lines between the rapid estimate method and the IS method were generally within 20% of unity, in agreement with the manufacturer's claim. Semiquantitative estimates based on RF also showed good agreement with results obtained using multipoint calibration. These estimates were sufficient for clinical differentiation of routine and toxic levels. Our study demonstrated that the REMEDi HS is particularly useful for a rapid estimate of drug concentrations in the samples from emergency cases when calibrators are not readily available. Our study also showed that this system can be used for the therapeutic monitoring of ranitidine, bromisovalum, lidocaine, and diphenhydrmine.