Importance of dosimeter calibration method on nebulizer output.

BACKGROUND: We have observed that dosimeter-run nebulizers have a much smaller output when manually activated than when breath activated; however, this has not been adequately investigated. OBJECTIVE: To evaluate the effect of different calibration methods on nebulizer output. METHODS: Six healthy subjects performed all calibrations. The nebulizers were operated by 2 different dosimeters and were calibrated to produce 9 microL per actuation by breath activation followed by exhalation to the room. The nebulizers were then operated at these identical settings, and the output determined in 3 ways: (1) breath activation followed by exhalation to the room, (2) breath activation with exhalation into the nebulizer, and (3) manual activation (with no subject using the nebulizer). These 3 methods were termed regular, rebreathe, and manual, respectively. RESULTS: There was a large and statistically significant difference in nebulizer output among the 3 methods. The measured rebreathe outputs (5.6 and 5.7 microL per actuation) were approximately two thirds and the manual outputs (3.2 and 3.9 microL per actuation) were approximately one third of the regular calibration outputs (8.6 and 8.9 microL per actuation); the 2 values are for the 2 dosimeters. The results were highly statistically significant (P < .001). CONCLUSIONS: The method by which a nebulizer-dosimeter system is calibrated results in different nebulizer outputs. This has a high likelihood of influencing the concentration of methacholine causing a 20% decrease in volume in the first second of forced expiration.     

Systematic review of the treatment of cancer-associated anorexia and weight loss.

PURPOSE: We systematically assessed the efficacy and safety of appetite stimulants in the management of cancer-related anorexia. Literature databases were searched for randomized controlled trials of appetite stimulants in the treatment of cancer anorexia. MATERIALS AND METHODS: Studies were graded according to quality. Fifty-five studies met inclusion criteria. RESULTS: Only two drugs have evidence to support their use for anorexia (progestins and corticosteroids). There is strong evidence against the use of hydrazine sulfate. The outcomes of these trials have been mixed and patient population heterogeneous. CONCLUSION: The optimal dose, time to start, and duration of treatment for many appetite stimulants for cancer anorexia is still unknown. A more systematic approach to research methodology with universal outcome measure and prospective randomized studies are need. Combination regimens are needed but this cannot at the present time be supported by the data presented.     

Studies on the properties of some peripheral MAO inhibitors

1. Studies were carried out on three monoamine oxidase (MAO) inhibitors, two of which, debrisoquine and para- hydroxyphenelzine, are purported to be peripheral inhibitors and one, phenelzine, is a peripherally acting inhibitor, which has been included for comparitive purposes. 2. All three showed varying degrees of specificity towards MAO type A. 3. The action of debrisoquine was very rapid as was that of para- hydroxyphenelzine. 4. The inhibition caused by debrisoquine was competitive and reversible, while that caused by both phenelzine and para- hydroxyphenelzine was irreversible. 5. The inhibition caused by debrisoquine appeared to be unaffected by the pH of the medium.     

Subarachnoid injection as a complication of retrobulbar anesthesia

We studied eight cases of apparent subarachnoid injection of local anesthetic through the optic nerve sheath and subsequent spread to the parabrainstem cisterns and the contralateral optic nerve sheath. The patients all experienced bilateral decrease in vision and ophthalmoplegia, and variable degrees of central nervous system symptoms and respiratory depression. The complications occurred with a variety of local anesthetic agents and with sharp disposable needles in six of the eight cases. These cases demonstrated the spectrum of signs and symptoms that may follow optic nerve sheath injection of local anesthetic agents.     

Administered radiopharmaceutical doses in children: a survey of 13 pediatric hospitals in North America.

Universally applied standards for administering radiopharmaceutical doses in children do not presently exist. Hence, pediatric radiopharmaceutical dosimetry varies considerably from institution to institution and is generally based on the recommended adult dose adjusted for body mass. METHODS: We surveyed 13 pediatric hospitals in North America to obtain objective data on dosimetry practices for 16 pediatric nuclear medicine examinations, including the minimum total radiopharmaceutical administered dose per examination, the total administered dose based on body mass, and maximum total doses in children. RESULTS: The reported administered doses of radiopharmaceuticals to children vary over a relatively large range, especially with respect to minimum total administered doses. CONCLUSION: This survey has identified a broad range of administered doses directly leading to variability in radiation-absorbed doses to patients. The nuclear medicine community should develop pediatric standards for radiopharmaceutical administered doses and reduce radiation exposure in children, such as through the use of modern software reconstruction techniques.     

Implications of admission hypothermia in trauma patients

Hypothermia is common after severe injury, and has been associated with an increased mortality rate in patients stratified by anatomic indices of injury severity. In this retrospective study of 173 patients, early post-traumatic hypothermia was found to correlate with physiologic indicators of volume deficit, independently of the amount of intravenous fluid received. There was no correlation found between admission core temperature and time from injury, blood alcohol, or presence of severe closed head injury. Hypothermic patients (less than 35 degrees C) had a lower predicted probability of survival and a higher mortality rate than euthermic patients (greater than or equal to 35 degrees C). However, when patients were stratified by physiologic and anatomic indicators of injury severity, mortality rates among the euthermic and hypothermic patients were not significantly different. Early post-traumatic hypothermia does not appear to exert an independent effect upon outcome.     

Paramyosin is the Schistosoma mansoni (Trematoda) homologue of antigen B from Taenia solium (Cestoda)

Antigen B, a major antigen of the cestode parasite Taenia solium, has been purified and a portion of amino acid sequence obtained. Paramyosin of the trematode parasite Schistosoma mansoni, an immunogenic protein that has shown promise as a vaccine candidate, has several biochemical and immunological properties in common with antigen B. A full-length cDNA clone of S. mansoni paramyosin has been obtained and the predicted translation product contains a sequence that is highly homologous to the sequence obtained for antigen B. The predicted amino acid composition and isolectric point of paramyosin are nearly identical to those established for antigen B. Recombinant S. mansoni paramyosin, expressed in Escherichia coli as a fusion protein with beta-galactosidase, was recognized by antisera against T. solium antigen B. We conclude from these results that S. mansoni paramyosin and T. solium antigen B are homologous proteins. Since S. mansoni paramyosin is thought to be a muscle protein and T. solium antigen B a secreted glycoprotein with anti-complement activity, this conclusion raises some interesting questions regarding the role of this class of proteins in the host-parasite relationship.     

Potential interference of agents on radioiodide thyroid uptake in the euthyroid rat.

The objective of this research was to investigate the merits of controlled studies with euthyroid rats as a means of determining the influence of dose and time after administration of agents that may interfere with radioiodide uptake in the thyroid. METHODS: Potassium iodide (KI), propylthiouracil (PTU), diatrizoate meglumine, and iohexol were selected to represent interfering agents. Two dose levels per agent were investigated. Doses used were 1 and 2 mg/kg of body weight for KI, 3.5 and 7 mg/kg of body weight for PTU, 1 mL/kg (282 mg I/kg) and 2 mL/kg (564 mg I/kg) of body weight for diatrizoate meglumine, and 1 mL/kg (300 mg I/kg) and 2 mL/kg (600 mg I/kg) of body weight for iohexol. The 24-h radioiodide thyroid uptake was determined after (131)I was given at 1, 8, 15, and 22 d after administration of interfering agents. RESULTS: The percentage radioiodide uptake value for the thyroid decreased significantly compared with controls for all agents and both doses on day 1 but returned to control levels by day 22 for all agents and both doses The time to return to normal varied between agents and doses. CONCLUSION: We conclude that the interfering agent, the dose given, and the length of time after administration influence the potential for an agent to affect radioiodide uptake in the thyroid. Further studies with the rat, preferably hyperthyroid, would be beneficial in generating data to reduce confusing contradictory information on the length and severity of interference of agents in radioiodide thyroid studies.