Acoustic microscopy system: design and preliminary results.

An acoustic microscopy system was designed to perform 2D imaging in the C-plane with a single-element transducer. The ultrasound transducer was fabricated by polishing bulk lithium niobate (LiNbO(3)) to the required thickness (approximately 60 or 45 micro) for the desired operating frequency (55 or 75 MHz). The polished LiNbO(3) was attached to acoustic backing and matching layers. Finally, an epoxy lens was applied and the transducer mounted in a housing. The transducer was mounted in a 3D motorized positioning stage and operated by a high-frequency pulser/receiver. Received echoes were sampled with a 2 GHz ADC card and displayed on a PC using software developed in the Matlab environment. Transducer frequency and bandwidth were measured off a steel plate positioned at the focal length. A penny was scanned initially to confirm expected performance before acquiring data from liver (n=3) and spleen (n=3) specimens. For the first probe, the peak frequency was 54.05 MHz with a -6 dB bandwidth of 6.76 MHz. The axial and lateral resolutions were estimated to be 114 and 188 microm, respectively. For the second probe, the peak frequency was measured to 82 MHz with a -6 dB bandwidth of approximately 23 MHz. The axial and lateral resolutions were estimated to be around 33 and 81 microm, respectively. C-scans of the penny clearly showed detailed structures on front and back, while the capsule and the trabecular structures of the splenic tissues could easily be separated in different layers. In conclusion, an acoustic microscopy system operating at 55-75 MHz has been constructed and the feasibility of obtaining high-resolution images of tissue specimens demonstrated.

Risk factors for adverse drug reactions communication of the CHDM.

In the CHDM (Comprehensive Hospital Drug Monitoring for Adverse Drug Reactions, Bern/St. Gallen), the data of the 34,838 computer registered patient admissions 1974-1988 were available for evaluation. We summarize the results of three different studies: 1. A multivariate analysis of the risk factors to developed an ADR during hospital stay, mainly the number of drugs, age, sex and renal function. 2. The occurrence rate of hyperkalemia under the treatment with diurectics, mainly potassium (K+)-losing with K+ substitution compared to the combination of K(+)-sparing with K(+)-losing preparations. 3. The occurrence-rate of exanthema in relation to amino-penicillin preparations an allopurinol. The results are presented in the communication. (Tab 7, Fig. 1, Ref. 15). Ref. 15.).

[Acute severe dyspnea as a side effect of drugs. Report from the CHDM (Comprehensive Hospital Drug Monitoring)]. / Akute schwere Dyspnoe als Medikamentennebenwirkung. Mitteilung aus dem CHDM (Comprehensive Hospital Drug Monitoring).

This "syndrome" has been observed in 4 of 23,935 in-patients registered in the years 1974-1987 in the Comprehensive Hospital Drug Monitoring (Bern/St. Gallen), with 6 reactions. Signs of an attack of bronchial asthma, laryngeal or pulmonary edema or a (heart-)circulatory event were not observed. Each patient was cyanotic and 3 had the feeling of impending death. The eliciting drugs were penicillin-G (twice) and cefazolin (once), given i.v.; iron dextran i.m. (once); pitressin tannate i.m. (once) and dicobalt edetate (Kelocyanor) i.v.(once). In each case the reaction started during or shortly after injection of the drug; the duration of the reaction in 5 of these events was 20-80 minutes. The pathomechanism could be a special form of anaphylactic reaction with acute pulmonary hypertension, comparable to IgE-induced anaphylaxis in the rabbit or aggregate anaphylaxis in the monkey or the dog. Further observations are needed for more detailed study.

Time pattern of allergic reactions to drugs.

Generalized, allergic reactions to drugs show time patterns different from those based on pharmacological concepts. We distinguish three types of reactions: acute reactions (reaction time (RT): 0-60 minutes), subacute reactions (RT: 1-24 hours) and reactions of the latent type (RT: 1 day to several weeks). In this study, allergic reactions in the strict sense are supplemented by reactions considered to be based on intolerance or idiosyncrasy to aspirin, pyrazolones, paracetamol, NSAIDs, quinidine, iodine-containing contrast media and some as yet not understood reactions to local anaesthetics. Out of a total of 23,935 drug monitoring patients with 32,317 hospitalizations in the clinical divisions of internal medicine at three Swiss hospitals during the 1974-1987 period, 951 patients with 1,040 probably or definitely drug-related events of the selected type were recorded. Ultimately, 287 patients with 310 adverse drug reactions (ADRs) fulfilled our selection criteria and were classified into six groups of syndromes (Table 1). (Of the reactions described as maculopapular rash, unspecified rash and special exanthema, only the 159 reactions from the 1985-1987 period out of a total of 889 reactions of this type observed during the whole study period were included in our secondary evaluation.) The total number of 310 reactions (100%) showed the following RT distribution: 36 (11.6%) were of the acute type, 13 (4.2%) of the latent type, 12 (3.9%) could be interpreted as two distinct possible types of reaction to different drugs, and for 3 (1.0%) reactions, the type of reaction was indeterminable. The majority of reactions, 246 (79.4%), were of the subacute type starting within 24 hours of the last drug exposure. Among the 36 reactions of the acute type, 7 events of acute severe dyspnoea were observed which seemed to be as life-threatening as anaphylactic or anaphylactoid shock. These hospital-epidemiological data are of interest for focusing basic research and developing further principles of drug safety.