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.     

Regulation of ketogenesis, gluconeogenesis, and glycogen synthesis by insulin and proinsulin in rat hepatocyte monolayer cultures

The metabolic actions of porcine insulin and biosynthetic human proinsulin on fatty acid and glucose metabolism were studied in rat hepatocytes cultured in monolayer for 24 h. Our aim was to establish whether proinsulin action in the liver is similar to insulin action and whether the relative potencies of the two hormones are the same for different metabolic processes. Proinsulin and insulin exerted a similar maximal inhibitory effect on ketone body formation from palmitate and on gluconeogenesis from pyruvate. The half-maximal effective concentration of proinsulin was 11-13 times that of insulin. The antiketogenic effects of insulin and proinsulin were associated with an increased glycerol 3-phosphate content and a decreased affinity of carnitine palmitoyltransferase for its substrate palmitoyl-CoA. When the basal rate of ketogenesis was increased with isobutyl methylxanthine, the half-maximal effective concentrations of both proinsulin and insulin were decreased, but the relative potency of the two hormones was unchanged. Proinsulin and insulin exerted similar maximal stimulatory effects on glycogen synthesis and on the activities of pyruvate kinase, glucose 6-phosphate dehydrogenase, phosphogluconate dehydrogenase, and malic enzyme. The half-maximal effective concentration of proinsulin was 10-30 times that of insulin. These findings are consistent with receptor binding studies on liver membranes that suggest that proinsulin interacts with insulin-specific and not proinsulin-specific receptors. Our findings also suggest that proinsulin action does not differ from insulin action at a postreceptor site.     

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.     

Pain and faulty breathing: a pilot study

The purpose of this pilot study was to observe both relaxed and deep breathing patterns in a convenience sample to determine the incidence of normal versus faulty patterns of respiration. These observations were then combined with respondent answers to a survey on pain history to determine if there is any correlation between faulty breathing and musculo-skeletal pain patterns. If such a correlation can be made, then we propose that clinicians working with chronic pain patients may have improved outcomes if they address and correct faulty breathing patterns. Based on this study, it is suggested to include the evaluation and treatment of faulty respiration in the rehabilitation of chronic musculo-skeletal conditions, most notably cervical pain.     

Effects of a monoclonal antibody raised against nerve growth factor on skeletal pain and bone healing after fracture of the C57BL/6J mouse femur.

A closed femur fracture pain model was developed in the C57BL/6J mouse. One day after fracture, a monoclonal antibody raised against nerve growth factor (anti-NGF) was delivered intraperitoneally and resulted in a reduction in fracture pain-related behaviors of approximately 50%. Anti-NGF therapy did not interfere with bone healing as assessed by mechanical testing and histomorphometric analysis. INTRODUCTION: Current therapies to treat skeletal fracture pain are limited. This is because of the side effect profile of available analgesics and the scarcity of animal models that can be used to understand the mechanisms that drive this pain. Whereas previous studies have shown that mineralized bone, marrow, and periosteum are innervated by sensory and sympathetic fibers, it is not understood how skeletal pain is generated and maintained even in common conditions such as osteoarthritis, low back pain, or fracture. MATERIALS AND METHODS: In this study, we characterized the pain-related behaviors after a closed femur fracture in the C57BL/6J mouse. Additionally, we assessed the effect of a monoclonal antibody that binds to and sequesters nerve growth factor (anti-NGF) on pain-related behaviors and bone healing (mechanical properties and histomorphometric analysis) after fracture. RESULTS: Administration of anti-NGF therapy (10 mg/kg, days 1, 6, and 11 after fracture) resulted in a reduction of fracture pain-related behaviors of approximately 50%. Attenuation of fracture pain was evident as early as 24 h after the initial dosing and remained efficacious throughout the course of fracture pain. Anti-NGF therapy did not modify biomechanical properties of the femur or histomorphometric indices of bone healing. CONCLUSIONS: These findings suggest that therapies that target NGF or its cognate receptor(s) may be effective in attenuating nonmalignant fracture pain without interfering with bone healing.