Biomedical subjects
Publications and source records attributed to R Chrzanowski.
Three cases of arthroplasty in the course of syringomyelia are presented. These patients have been diagnosed in orthopedic-traumatologic department due to their bony/articular symptoms. After having established the diagnosis the patients were referred to Neurosurgery. Final diagnosis of syringomyelia requires computerized tomography and magnetic resonance imaging. Syringomyelia necessitates an early surgical treatment.
A simulation model of the effects of hormone replacement therapy (HRT) on hip fractures and their consequences is based on a population of 100,000 post-menopausal women. This cohort is confronted with literature derived probabilities of cancers (endometrium or breast, which are contra-indications to HRT), hip fracture, disability requiring nursing home or home care, and death. Administration of HRT for life prevents 55.5% of hip fractures, 22.6% of years with home care and 4.4% of years in nursing homes. If HRT is administered for 15 years, these results are 15.5%, 10% and 2.2%, respectively. A slight gain in life expectancy is observed for both durations of HRT. The net financial loss in the simulated population is 222 million Swiss Francs (cost/benefit ratio 1.25) for lifelong administration of HRT, and 153 million Swiss Francs (cost/benefit ratio 1.42) if HRT is administered during 15 years.
The assessment of medical technologies has to answer several questions ranging from safety and effectiveness to complex economical, social, and health policy issues. The type of data needed to carry out such evaluation depends on the specific questions to be answered, as well as on the stage of development of a technology. Basically two types of data may be distinguished: (a) general demographic, administrative, or financial data which has been collected not specifically for technology assessment; (b) the data collected with respect either to a specific technology or to a disease or medical problem. On the basis of a pilot inquiry in Europe and bibliographic research, the following categories of type (b) data bases have been identified: registries, clinical data bases, banks of factual and bibliographic knowledge, and expert systems. Examples of each category are discussed briefly. The following aims for further research and practical goals are proposed: criteria for the minimal data set required, improvement to the registries and clinical data banks, and development of an international clearinghouse to enhance information diffusion on both existing data bases and available reports on medical technology assessments.
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We investigated changes in angiotensin converting-enzyme (ACE) activity before and at 5, 15, 60, and 240 min after 20 micrograms phorbol myristate acetate/kg body wt iv in conscious rabbits. ACE activity was estimated in vivo from the single-pass transpulmonary metabolism of the synthetic substrate [3H]benzoyl-Phe-Ala-Pro [( 3H]BPAP) under first-order reaction conditions. Within 5 min after PMA administration, all animals developed profound granulocytopenia (15% of control) and moderate thrombocytopenia (57% of control), both lasting for the duration of the experiment. Concomitantly, there was a significant decrease in the transpulmonary metabolism of [3H]BPAP and the calculated apparent first-order reaction constant Amax/Km of ACE for [3H]BPAP. No histological evidence of lung injury was observed at these times. Since a concomitant fall in the permeability surface area product for urea was also observed, we considered that the apparent decline in ACE activity might have resulted from a reduction in perfused endothelial surface area. To resolve this, we studied the effect of PMA on the Km (a measure of enzyme affinity for its substrate) and Amax (a derivative of Vmax that is dependent upon total enzyme present and thus capillary surface area) of ACE and 5'-nucleotidase for [3H]BPAP and [14C]AMP, respectively. A significant increase in Km for both enzymes was observed at 1 h after PMA, whereas Amax was unaffected, suggesting that low-dose PMA may indeed produce endothelial cell enzyme dysfunction independent of its effect on capillary surface area. These results provide evidence of pulmonary capillary functional injury before or in the absence of structural endothelial damage.
The effects of ANTU-induced acute pulmonary capillary injury on lung and serum ACE functional activity and the specific accumulation of radio-labelled anti-ACE in lung were explored. Rats were injected either with ANTU or the solvent and sacrificed at various intervals up to one week after injection. All ANTU-injected animals developed pulmonary edema and bilateral pleural effusions which resolved by the one week time point. At no time was there any significant change in serum ACE levels. The specific activity of total lung ACE however rose from 11.0 +/- .95 (mean +/- SEM) to 18.4 +/- 1.1 by two hours after ANTU; by 24 hours, however, solubilized lung ACE had fallen significantly to 6.9 +/- .79 (p less than .01). Total lung ACE had returned to control values by one week. In parallel groups of animals the accumulation of 125I-labelled anti-ACE (AA) or normal sheep immunoglobulin (NSG) was compared in control and ANTU-treated rats. The ratio of the radioactivity in the lungs of AA--injected animals to that in NSG--injected animals fell significantly after ANTU administration (5.0 +/- .88 to 1.2 +/- .28 at 2 hours) suggesting that immunoreactive ACE had fallen despite an increase in ACE functional activity. The decreased binding of AA at the early time points perhaps reflects internalization of endothelial cell ACE in response to injury and an inability of the antibody to interact with the enzyme. The reduction in binding at 24 hours (1.38 +/- .47) correlates with a reduction in total lung ACE. ANTI-ACE may be a useful reagent for quantitating endothelial cell damage following lung injury.
The need for assessment of new medical technologies has recently become evident in many countries, especially for the people responsible for health care policy. There are multiple reasons for making evaluation: rising costs in health care, medical efficacy, safety, as well as social and political issues. Each stage of life of a diagnostic, therapeutic or preventive technology, from its emergence to obsolescence, can be assessed by an appropriate procedure. In Switzerland, a country with decentralized health care as well as political systems, the assessment is made by various institutions. Evaluative aspects are included in some National Research Foundation programs. Most work, however, is done by the division of medical techniques at the Swiss Hospital Institute. The panel of experts has recently prepared a report on magnetic resonance imaging (MRI). As a result of the initial evaluation, the need for this new technology in this country, and the number and sites of MRI systems for the next few years were established. The capital, running and unitary costs of this diagnostic procedure were estimated. The report will be of aid to the people planning investments and dealing with questions of reimbursement and other issues of health care policy. The methods of epidemiology, biostatistics, sociology and health economics used by the institutes of social and preventive medicine are very helpful in the procedures of technology assessment.
The Swiss Hospital Institute, a nonprofit institution that provides guidance on hospital planning and operation to Switzerland's health care community, conducted in 1984 a comprehensive study of magnetic resonance imaging (MRI) and magnetic resonance spectroscopy via a 17-member commission that examined all aspects of these emerging technologies. Future MRI utilization was estimated by developing five clinical categories of possible MRI use, based on ICD codes, and a probability of MRI utilization was developed for each category. By applying these probabilities to the number of inpatient admissions in each category, an annual nationwide volume of 20,000 scans was estimated. Ten MRI systems were considered adequate for a period of up to five years after the report's promulgation, based on a per-system annual throughput of 1,900-2,000 patients. A superconducting-magnet system with an 0.5-T field strength was deemed the most suitable, with units to be located in university hospitals. [Spectroscopy was considered best left to separate research installations.] The cost of equipment and construction for the 0.5-T superconducting magnet system were calculated as high as 3.6 million Swiss francs (Sfr) (approximately $1.65 million at fall 1985 exchange rates). the annual operating cost was estimated as Sfr 1.3 million ($600,000). On this basis a per-study fee of Sfr 690 ($315) was projected. The study recommended health insurance coverage of MRi use, only in patients with well-proven clinical indications for an MRI scan. The report is expected to aid in the orderly introduction of MRI into Switzerland's health care system.
Hypoxic-ischaemic brain lesions may be detected as low density (LD) areas by means of computerized tomography (CT), but the clinical significance of such LD areas has been controversial. Since timing might be a critical factor, we studied the temporal evolution of LD areas in 9 asphyxiated term babies who had had two or more CT, and compared the changes to the neurodevelopmental outcome. Scans were classified according to the elapsed time after asphyxia as early (day 1-7, n = 6), intermediate (week 2-4, n = 7; week 4-7, n = 3) and late CT (3 months or more, n = 7). In early scans, no, or only ill defined, LD areas were seen in the periventricular region. In intermediate CT's, LD-zones were further diminished in those babies who later were normal. Sharply accentuated LD areas, however, appeared in those who later suffered from neurodevelopmental disorders. These LD areas, probably representing hypoxic-ischaemic lesions, were located periventricularly, extending into the subcortical white matter and the cortex, and usually involved both hemispheres symmetrically. They began to disappear at 4 to 7 weeks in some regions, possibly because of glial proliferation. LD persisting more than 4-7 weeks tended to transform into cyst-like lesions, or marked atrophy. We conclude (1) that hypoxic-ischaemic lesions appear as zones of low density on CT scans performed after the first week and (2) that the extent of such lesions can best be assessed between 9 to 23 days after asphyxia.
Twenty-five asphyxiated term babies were investigated in order to evaluate the prediction of their neurodevelopmental outcome by means of computerized tomography (CT) as compared to neurological symptoms during the neonatal period. Low density (LD) areas, thought to represent hypoxicischaemic lesions, were assessed quantitatively by means of a LD score based on the extent and degree of LD, the total score ranging from 0-36. Neonatal scans were defined according to the time span elapsed between asphyxia and CT as (1) early CT (day 1-7, n = 15), and (2) intermediate CT (day 9-23: n = 14; day 29: n = 1). The newborns were classified according to the neonatal neurological findings as having mild (n = 8, 32%), moderate (n = 9, 36%), and severe (n = 8, 32%) encephalopathy, following the definition of Sarnat and Sarnat (1976). Among the twenty-two survivors, the follow-up (mean age 19.2 +/- 6.0 mts) revealed fourteen (56%) with normal outcome, two (8%) with transient neurodevelopmental anomalies during the first year, and nine (36%) with permanent abnormalities such as cerebral palsy and/or retardation (mainly global) and/or epilepsy. Early CT scans had no predictive value. Intermediate CT, however, showed distinct variations of LD areas which resulted in an LD score well correlated with the later outcome. In particular, a LD score below 14 characterized every baby who developed normally; a prediction not possible in a reliable way be means of neonatal neurological signs. For all abnormal children, the score correlated with the severity of the later neurodevelopmental disorder, except for one with the latest intermediate CT (day 29).
Cerebral computerized tomography (CT) was obtained in 37 children with congenital hemiparesis to document the type of cerebral anomalies found in this group, correlate them with various features of the neurological handicap and clinical history and determine the prognostic and practical value of this examination in a newly diagnosed case. The CT-findings were: 1. normal CT: 4 children (11%); 2. unilateral ventricular enlargement: 9 children (24%); 3. others (cortical and subcortical lesions): 24 children (63%). In this latter group, special patterns were found: a) focal ischemic lesions: 7 cases; b) cystic porencephaly: 2 cases; c) ventricular deformities with hydrocephalus: 7 cases; d) varia: 8 cases. The children with normal CT or unilateral ventricular enlargement had mild or moderate hemiparesis without epilepsy or mental retardation. The third group comprised the more severe cases but the prognosis was very variable. The different types of CT-lesions, their possible origin and neuropathological correlates are described and compared with two previous studies. The variety of lesions found in this series and the relative prognostic value of the CT-Scan justify this examination in a newly diagnosed case.
Atropine sulfate was successfully administered endotracheally to a 74-year-old patient suffering profound bradycardic cardiovascular collapse. Ninety seconds following endotracheal atropine administration, normal blood pressure and pulse were established. Therapeutic blood levels of atropine were documented following endotracheal administration. The endotracheal route for atropine administration appears to provide an effective alternative route of administration when intravenous access is difficult or impossible to establish rapidly.
A review of the contrast media used for myelography and radiculography is presented. Water-soluble, nonionic medium like metrizamide enables the examination of the entire CSF space. The relation of the diagnostic benefit to complications when using this contrast medium is favorable. Attention must be paid in using the correct myelographic technique and in controlling the possible severe adverse reactions which appear in 1.5% of the cases during 24 h after the examination.
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A case of a cholesterol-containing granuloma of the orbit studied by bone scanning and selective carotid angiography is presented. Bone scanning with 99mDisphosphonate disclosed a solitary focus of intense activity in the right orbitofrontal region. On the selective angiogram of the right external carotid artery a faint vascular blush was found in the orbital wall.
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