Biomedical subjects
Publications and source records attributed to A Noe.
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Changes in the diameter of extracranial and intracranial arteries resulting in changes in cerebral blood flow have previously been assumed to be the most important pathophysiological factor in migraine. To test this hypothesis 20 normal subjects, and three groups of patients (n = 29) with migraine were investigated by means of transcranial Doppler sonography. Blood flow velocities in the middle cerebral (MCA) and in basilar (BA) arteries were measured. Data from patients were obtained in the interval between migraine attacks, during migraine attacks and following treatment with either ergotamine (0.5 mg i.m.; n = 10); flunarizine, a calcium overload blocker (20 mg i.v.; n = 13); or a 5-HT1-like agonist (sumatriptan, 4 mg s.c.; n = 6). Ergotamine and sumatriptan are constrictors of cerebral arteries in animal experiments. The arithmetic mean of flow velocity in the BA was reduced in normal subjects (45 cm/s) as compared with patients with migraine measured in between attacks (53 cm/s). Mean flow velocity in MCA was not different in normals (72.5 cm/s) as compared with migraineurs (75 cm/s). Neither ergotamine nor the 5-HT1 agonist and flunarizine resulted in a significant change in blood flow velocity in MCA and BA. This was true irrespective of whether the drugs were given in the headache-free period, during a migraine attack or during the withdrawal phase of drug-induced headache. Ergotamine was effective in improving headache during migraine attacks and sumatriptan attenuated headache during drug withdrawal from chronic analgesic intake. These results indicate that the action of ergotamine and the 5-HT1-receptor agonist is probably not mediated by their vasoconstrictor action on cerebral arteries.
BACKGROUND: The present study was designed to evaluate the efficiency of a newly developed troponin T enzyme immunoassay for the detection of acute myocardial infarction. METHODS AND RESULTS: The study comprised 388 patients admitted with chest pain and suspected myocardial infarction and 101 patients with skeletal muscle damage and additional suspected myocardial cell damage. Troponin T was elevated to more than twice the analytical sensitivity of the assay (0.5 microgram/l) in all patients with non-Q wave (range, 1.2-5 micrograms/l) and Q wave infarction (range, 3-220 micrograms/l). Troponin T appeared in serum as early as 3 hours after onset of pain in 50% of the patients and remained elevated in all patients for more than 130 hours, revealing release kinetics of both free cytosolic and structurally bound molecules. The diagnostic efficiency of troponin T was superior to that of creatine kinase-MB (98% versus 97%) and remained at 98% until 5.5 days after admission, if patients with unstable angina were excluded from analysis. In the 79 patients with unstable angina, troponin T was elevated (range, 0.55-3.1 micrograms/l) in at least one blood sample from each of 37 patients (56%). Circulating troponin T was correlated to the presence of reversible ST segment or T wave changes on the electrocardiogram (p less than 0.005) and to the frequency of in-hospital complications. In the 101 patients with skeletal muscle damage and suspected additional cardiac muscle damage, troponin T was the most useful test; its efficiency was 89% or 94% (depending on the discriminator value used) as compared with 63% for creatine kinase-MB. CONCLUSIONS: Thus, the data of the study indicate that the newly developed troponin T test improves the efficiency of serodiagnostic tools for the detection of myocardial cell necrosis as compared with conventionally used cardiac enzymes.
Healthy subjects were given single intravenous doses of ciprofloxacin, azlocillin, and the two drugs simultaneously on separate occasions. High-pressure liquid chromatographic analysis was used to assay the concentrations of both drugs in serum and urine. Pharmacokinetic parameters were calculated by noncompartmental methods. The total body (CL), renal (CLR), and nonrenal (CLNR) clearances; steady-state volume of distribution (Vss); and fractional urinary excretion of ciprofloxacin were all markedly decreased with the simultaneous administration of azlocillin. The disposition of azlocillin was unchanged when it was given with ciprofloxacin compared to when it was given alone. The pharmacokinetic parameters (mean +/- standard deviation) of ciprofloxacin given alone versus in combination with azlocillin were as follows: CL, 52.2 +/- 9.2 versus 33.9 +/- 6.0 liters/h (P less than 0.0005); CLR, 26.5 +/- 4.8 versus 16.2 +/- 4.2 liters/h (P less than 0.0005); CLNR, 25.8 +/- 5.5 versus 17.7 +/- 4.0 liters/h (P less than 0.03); Vss, 224 +/- 30 versus 166 +/- 41 liters (P less than 0.01); fractional urinary excretion, 0.56 +/- 0.06 versus 0.43 +/- 0.04 (P less than 0.002), respectively. This interaction resulted in significantly higher and more prolonged concentrations of ciprofloxacin in serum, which may be beneficial in the treatment of serious gram-negative bacterial infections, but it could also produce greater toxicity or result in more pronounced effects on oxidative drug metabolism of other medications.
The stability and compatibility of ciprofloxacin with selected drugs in intravenous admixtures were studied. Ciprofloxacin 2 mg/mL in 5% dextrose was combined with each of 22 other drugs at concentrations commonly used in clinical practice. Each combination was maintained at room temperature (approximately 22 degrees C) in constant fluorescent light. Immediately after preparation and at 6 and 24 hours, each admixture was examined visually in normal fluorescent room light and the pH value was determined. For samples lacking visible precipitates or having pH changes of not more than 1 unit, ciprofloxacin concentration was assayed by using high-performance liquid chromatography. When combined with ciprofloxacin, 14 of the study drugs did not alter the concentration of ciprofloxacin, including amikacin sulfate, atracurium besylate, aztreonam, cimetidine hydrochloride, dobutamine hydrochloride, fluconazole, gentamicin sulfate, metronidazole (intravenous, ready to use), midazolam hydrochloride, norepinephrine bitartrate, pancuronium bromide, potassium chloride, tobramycin sulfate, and vecuronium bromide. There were five drugs that were determined to be incompatible with ciprofloxacin because of precipitate formation (amphotericin B, ampicillin sodium/sulbactam sodium, cefuroxime sodium, piperacillin sodium, and sodium bicarbonate). Incompatibility with ciprofloxacin based on pH changes of more than 1 unit was found with four drugs: ampicillin sodium/sulbactam sodium, ceftazidime, metronidazole hydrochloride (powder only), and ticarcillin disodium/clavulanate potassium. Intravenous ciprofloxacin 2 mg/mL admixed in 5% dextrose was stable and compatible with 14 of the 22 test drugs for up to 24 hours at room temperature. The other eight drugs should not be combined with ciprofloxacin.
The author provides an historical and current view of the work of the Human Developmental Anatomy Center of the National Museum of Health and Medicine of the Armed Forces Institute of Pathology in Washington, DC. A project to create and disseminate electronic images from the extensive holdings, as presented at a 1994 National Institutes of Health conference, is described.
We have designed a prototype knowledge management online environment for the biomedical sciences which integrates access to online representations of the scientific literature, bibliographic databases, high-performance visualization technologies, large-scale scientific databases, and tools for authoring new-generation scientific publications. This system will provide widespread access to its resources by using the World Wide Web for its underlying architecture. This system expands upon our Weblet Interactive Remote Visualization (IRV) server technology to produce a set of dedicated Internet "visualization servers" which provide interactive control of real-time visualizations from the Visible Embryo Project database from within Web pages viewed with our WebRouser software package. This system will be used to develop a set of prototype applications for both online education of medical students in developmental anatomy and for an interactive patient education system for expectant parents. We recognize that knowledge represented by these national resource databases is not static, therefore it is essential to include tools for both the creation of new "compound documents" which incorporate embedded objects, as well as for managing the peer-review of scholarly publications, in order to ensure the integrity of new knowledge as it is added to these databases in the future. We have therefore begun to design integrated tools for our system which facilitate both the creation of and the validation of new generations of scientific knowledge.
Since the origination of the Human Developmental Anatomy Center at the National Museum of Health and Medicine of the Armed Forces Institute of Pathology, efforts have been made to use electronic media to assist researchers wishing to use collections housed there. Earlier projects involved creating high-resolution images of the thousands of sections in the collections; later efforts involved creating three-dimensional models; later still, these images and models have been placed in a World Wide Web format for ease of distribution. This article assesses the utility of the project and anticipates future uses of the growing website.
Uptake of apomorphine and elimination kinetics in brain and muscle tissue of the weakly electric fish Gnathonemus petersii (Mormyridae) was determined by HPLC. 20 min exposure of the fish to apomorphine in the aquarium water (0.4 mg/l) resulted in a concentration factor of 1.09 for brain and 0.55 for muscle tissue. Elimination from brain tissue can be described with first order kinetics (t1/2 = 2.4 h).
With the advent of the 21st century, the Armed Forces Institute of Pathology is delivering online medical consultation to the global health care community. By incorporating widely available open system technology into the paradigm of telepathology, the AFIP is providing world class expertise in pathology and access to a wealth of information for physicians and the general public. The national treasure known as the Armed Forces Institute of Pathology has more than a glorious history; it has a pretty bright future, too.