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Biomedical subjects

K Spitzer

Publications and source records attributed to K Spitzer.

32 records · Page 2Linked to original sources

The Hamburg Stroke Data Bank: goals, design and preliminary results.

A stroke data bank has been developed which consists of 1500 items, including clinical and laboratory findings, past medical history, treatment and outcome. In addition to previously published registries, the Hamburg Stroke Data Bank allows storage of time-dependent data: multiple findings can be entered at different times after stroke onset. The data bank runs on any MS-DOS microcomputer and can be operated without computer knowledge. The stroke registry is conceived to support a prospective, local, multicentre study of stroke. This paper describes objectives, data bank structure and preliminary results of the pilot phase, which includes data of 441 patients with completed stroke and reversible ischaemic deficits. Demographic characteristics, incidence of stroke types, associated risk factors and outcome are evaluated.

Adolescent↗

NERVTRACK--a neuroanatomical data bank.

To provide the neurologist with a detailed and easily accessible neuroanatomical reference, we have developed a data bank including all relevant efferent and many afferent neuroanatomical pathways. NERVTRACK contains 4000 anatomical data items arranged in a tree-like manner reflecting structural and functional relationships. The program is able to address problems like the following: (1) What is the spinal, radicular, and peripheral innervation of a given muscle? (2) Which muscles are affected by a lesion of a given peripheral nerve, a root, or a segment of the spinal cord? (3) For a given muscle, what are synergists and antagonists, and which clinical test is applicable to evaluate its strength? NERVTRACK runs on IBM-compatible microcomputers, even on lap tops. It is a fast and comfortable reference for clinical practice and serves as a readily accessible teaching aid.

Expert Systems↗

The MICROSTROKE expert system for stroke type diagnosis.

MICROSTROKE is a prototype expert system designed to categorize and diagnose stroke types based on clinical information. The knowledge base of MICROSTROKE includes information from large stroke registries. The system first queries the physician-user for details of the patient's history, information about the onset of stroke, accompanying symptoms, and pertinent neurologic findings and then sums the individual data items, factors in the a priori odds, and arrives at the probabilities of different stroke types for a given patient. Specific diagnosis of stroke type includes thrombosis, embolus, lacune, intracerebral hemorrhage, and subarachnoid hemorrhage. Stroke type diagnoses by MICROSTROKE were correct in 72.8% of 250 cases in the Hamburg Stroke Data Bank. MICROSTROKE runs on any MS-DOS microcomputer and is intended as a practical aid for physicians not fully familiar with the diagnosis of stroke types.

Cerebrovascular Disorders↗

The TOPOSCOUT expert system for stroke localization.

Clinically, strokes are localized by the findings on neurologic examination. TOPOSCOUT is an expert system designed to diagnose the anatomic location and the corresponding vascular territory of strokes based on the clinical signs and symptoms. The inference engine of TOPOSCOUT uses a backtracking algorithm and a rule-based data base that includes associations of neurologic signs with vascular and anatomic areas. TOPOSCOUT is capable of detecting typical stroke patterns, for example, "top-of-the-basilar" or Wallenberg's syndromes. The accuracy of TOPOSCOUT's diagnoses has been tested for conformity with the final diagnoses of 129 patients in the Hamburg Stroke Data Bank, and a high level of agreement was found for hemispheric lesions. The program runs on microcomputers with MS-DOS and is intended as a practical aid for physicians not fully familiar with topologic stroke diagnosis and as an interactive teaching device.

Cerebral Arteries↗

Spontaneous subarachnoid haemorrhage: expert system for appraisal of the prognosis and computer-supported decision for therapy.

An expert system is presented which allows appraisal of the prognosis and a computer-supported decision for the therapy of patients with acute spontaneous subarachnoid haemorrhage (SAH). The knowledge of physicians as a synthesis of their own and other clinicians' experience is simulated with methods of artificial intelligence by setting up two data banks. In one data bank, selected information on the correlation between initial clinical parameters, on the one hand, and mortality, outcome and complications, on the other, from about 250 neurological publications is stored, taking into consideration the therapeutic regimens applied. A second data bank receives clinical and laboratory data profiles of a patient population which has already been treated. The expert system is able to compare the individual initial findings with the corresponding parameter combination stored in the data banks regarding the decision for therapy of a patient to be treated. This enables both calculation of the probable complications and prediction of the expected outcome in relation to various possible forms of therapy. The expert system can thus indicate the kind of therapy where the lowest number of complications and the best outcome can be expected, thus supporting the decision of the physician. As each new patient is treated, the volume of stored information increases, so the system possesses self-learning characteristics. To check the validity of the prognoses, the outcome estimated by the expert system for 51 patients with spontaneous SAH was compared with the actual outcome, and a high level of agreement was attained.

Decision Making, Computer-Assisted↗

[Prognostic significance of initial clinical and instrumental parameters in spontaneous intracerebral hemorrhages].

We retrospectively analyzed the records of 63 consecutive patients with spontaneous intracerebral hemorrhage (ICH) who had been treated in our neurological intensive care unit from 1981 to 1985 (aged 17 to 84 years). In this sample, the prognostic value of initial clinical and laboratory findings was studied. The following factors were significantly correlated with mortality: concomitant cardiac failure, general atherosclerosis, and chronic obstructive pulmonary disease; coma or deranged brainstem reflexes on admission; concomitant intraventricular or subarachnoid hemorrhage, hydrocephalus and midline shift on CT scan. ICH location did not significantly correlate with outcome. Among lobar ICH occipital hematomas carried the best prognosis. No prognostic importance was detected for age and gender, initial blood pressure, time interval between ICH and admission, ECG or angiographic findings, or laboratory values.

Aged↗

[Incidence and prognosis of internal medicine complications in spontaneous intracranial hematomas].

The records of 133 consecutive patients with spontaneous intracranial hemorrhage were reviewed to assess the frequency of systemic complications and their influence on outcome and neurological complications. The mean age of 63 patients with spontaneous intracerebral hemorrhage (ICH) was 11 years higher compared to 70 patients with spontaneous subarachnoid hemorrhage (SAH). Concomitant disease was more frequent in ICH than in SAH, and general atherosclerosis, chronic obstructive pulmonary disease and cardiac failure were associated with an increased mortality. 94% of all ICH and 79% of all SAH patients developed at least one systemic complication. A correlation was found between initial and late hyperglycemia, and high mortality rate and poor survival quality. In both groups an association of cardiac arrhythmias with intracranial pressure and an unfavourable outcome were observed. SAH patients with QT-prolongation had an increase in mortality and developed ischemic deficits more frequently. Pulmonary complications and disturbances of blood pressure regulation were associated with an unfavourable outcome, and in SAH patients with occurrence of neurologic complications.

Adolescent↗

A novel method for quantifying shape deformation applied to biocompatibility testing.

Cytotoxicity tests are important for the screening and evaluation of biocompatibility of artificial organs. Morphologic changes of cells that were contacted biomaterials or biomaterial extracts indicate their toxicity. However, information on cytotoxic effects is still obtained by subjective visual inspection of microscopic samples. In this article, a novel computer assisted method is introduced. The automatic analysis of digitized micrographs is achieved in several stages: segmentation, separation, classification, and measurement. The segmentation of the image is provided by a new local adaptive thresholding technique, which adapts the threshold window sizes onto local gray level distribution and yields optimal window sizes. The actual threshold is obtained by maximizing interclass variances and minimizing intraclass variance. For the separation of connected cells, the binarized samples are cleaned from "false" markers by morphologic filtering. The subsequent separation is a two phase approach. Information levels are generated top-down by successively applying an enhanced erosion operator, which yields markers and filters noise usually evolving from multiple erosions. The converse bottom-up integration of the eroded markers is performed by successively applying an enhanced dilation operator, which reconstructs the cells and prevents merging of already separated objects. The subsequent measuring provides quantitative parameters of the distribution of size and compactness of the cells contained within the sample. The method was evaluated by L-929 fibroblasts that were in contact with 0%, 5%, and 10% concentrations of ethanol. For each concentration, 268 images of the cell populations were captured. The obtained quantitative parameters are highly correlated to the common verbal description of morphologic changes. Therefore, the proposed automatic method has several advantages compared with subjective examinations. The results allow an objective comparison of the quantification of phenomena; the subjective influence of the observer is eliminated; and the laboratory staff is relieved of time consuming routine work.

Animals↗