Biomedical subjects
Richard Wenzel
Publications and source records attributed to Richard Wenzel.
The design of clinical trials that evaluate antifungal prophylaxis and combination therapy: introduction and overview.
On 8 February 2003, the second in a series of meetings in honor of John E. Bennett, M.D., was convened in New York City. A report from the previous meeting was published in 2003. The goal of this second meeting was to discuss the design of clinical trials in prophylaxis and combination therapy. This supplement presents 12 articles by leading clinicians who are currently active in trials in this area and presents a current view of the unmet needs and challenges.
Mobile, outdoor continuous-flow isotope-ratio mass spectrometer system for automated high-frequency 13C- and 18O-CO2 analysis for Keeling plot applications.
A continuous-flow isotope-ratio mass spectrometer (CF-IRMS, custom-made GasBenchII and Delta(plus)Advantage, ThermoFinnigan) was installed on a grassland site and interfaced with a closed-path infrared gas analyser (IRGA). The CF-IRMS and IRGA were housed in an air-conditioned travel van. Air was sampled at 1.5 m above the 0.07-m tall grassland canopy, drawn through a 17-m long PTFE tube at a rate of 0.25 L s(-1), and fed to the IRGA and CF-IRMS in series. The IRMS was interfaced with the IRGA via a stainless steel capillary inserted 0.5 m into the sample air outlet tube of the IRGA (forming an open split), a gas-tight pump, and a sample loop attached to the eight-port Valco valve of the continuous-flow interface. Air was pumped through the 0.25-mL sample loop at 10 mL s(-1) (a flushing frequency of 40 Hz). Air samples were analysed at intervals of approx. 2.8 min. Whole system precision was tested in the field using air mixed from pure CO2 and CO2-free air by means of mass flow controllers. The standard deviation of repeated single measurements was 0.21-0.07 per thousand for delta13C and 0.34-0.14 per thousand for delta18O of CO2 in air with mixing ratios ranging between 200-800 micromol mol(-1). The CO2 peak area measured by the IRMS was proportional to the CO2 mixing ratio (r2 = 1.00), allowing estimation of sample air CO2 mixing ratio from IRMS data. A 1-day long measurement cycle of CO2, delta13C and delta18O of air sampled above the grassland canopy was used to test the system for Keeling plot applications. Delta18O exhibited a clear diurnal cycle (4 per thousand range), but short-term (1-h interval) variability was small (average SD 0.38 per thousand). Yet, the correlation between delta18O and CO2 mixing ratio was relatively weak, and this was true for both the whole data set and 1-h subsets. Conversely, the delta13C of all 541 samples measured during the 25.2-h interval fitted well the Keeling regression (r2 = 0.99), yielding an intercept of -27.40 per thousand (+/-0.07 per thousand SE). Useful Keeling regressions (r2 > 0.9, average r2 = 0.96) also resulted from data collected over 1-h intervals of the 12-h long twilight and dark period. These indicated that 13C content of ecosystem respiration was approx. constant near -27.6 per thousand. The precision of the present system is similar to that of current techniques used in ecosystem studies which employ flask sampling and a laboratory-based CF-IRMS. Sampling (and measurement) frequency is greatly increased relative to systems based on flask sampling, and sampling time (0.025 s per sample) is decreased. These features increase the probability for sampling the entire CO2 range which occurs in a given time window. The system obviates sample storage problems, greatly minimises handling needs, and allows extended campaigns of high frequency sampling and analysis with minimal attendance.
Migraine headache misconceptions: barriers to effective care.
Migraine headaches affect 12% of the adult population in the United States and cause a significant economic loss due to decreased workplace productivity Although interactions between pharmacists and individuals with headache are common, few pharmacists receive adequate training regarding migraine therapy. We refute several misconceptions that hinder effective care, such as that migraine is a vascular disease, triptans cause rampant cardiacrelated morbidity and even mortality, a best oral triptan exists, sinus and tension headaches are prevalent, and migraine is a minor economic problem. Our pathophysiologic understanding demonstrates that migraine is a neurologic process of the trigeminovascular system, of which vascular effects are secondary. This process can result in a myriad of clinical signs and symptoms, often leading to a misdiagnosis of sinus or tension headache. The last decade's experience with triptans in more than half a billion people worldwide reveals a benign adverse-effect profile, particularly when taken early in an attack. Published reports and real-world experiences illustrate that these drugs do not merit fears of triptan-induced cardiac consequences in appropriately selected individuals. Society's productivity loss due to migraine is measured in billions of dollars. Restoring a patient's ability to function normally is now recognized as the primary treatment goal, not merely relieving pain. Thus, the overreliance on "pain killer" drugs such as butalbital-containing products and the continued underutilization of migraine-specific drugs need to be addressed. Opportunities exist for pharmacists and other health care providers to dispel continually propagated migraine misconceptions and familiarize themselves with advances in therapy. Such actions will benefit patients, the health care system, and society as a whole.
The case of the cold thermometers.
BACKGROUND: A temporal artery thermometer was introduced at our hospital. Immediately staff noted subnormal temperature readings. METHODS: Three serial evaluations of patient temperatures were done: August 2000 (initial), September 2000 (posteducation), and December 2000 (after removal of temporal artery thermometer). RESULTS: In the initial review, 89% of the readings were < 98.6 degrees F. Comparison of the readings from the last and first surveys showed a statistical increase in the proportion of readings > or =100.0 degrees F and decrease of readings <98.6 degrees F (P <.001). CONCLUSIONS: Our experience underscores the importance of performance data for quality monitoring of new products.
Practical approaches to migraine management.
Migraine is a recurrent clinical syndrome characterised by combinations of neurological, gastrointestinal and autonomic manifestations. The exact pathophysiological disturbances that occur with migraine have yet to be elucidated; however, cervico-trigemino-vascular dysfunctions appear to be the primary cause. Despite advances in the understanding of the pathophysiology of migraine and new effective treatment options, migraine remains an under-diagnosed, under-treated and poorly treated health condition. Most patients will unsuccessfully attempt to treat their headaches with over-the-counter medications. Few well designed, placebo-controlled studies are available to guide physicians in medication selection. Recently published evidence-based guidelines advocate migraine-specific drugs, such as serotonin 5-HT(1B/1D) agonists (the 'triptans') and dihydroergotamine mesylate, for patients experiencing moderate to severe migraine attacks. Additional headache attack therapy options include other ergotamine derivatives, phenothiazines, nonsteroidal anti-inflammatory agents and opioids. Preventative medication therapy is indicated for patients experiencing frequent and/or refractory attacks.