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Biomedical subjects

S Horner

Publications and source records attributed to S Horner.

30 records · Page 2Linked to original sources

Cerebrovascular risk factors in an elderly Austrian population: first year results of the Austrian Stroke Prevention Study (ASPS).

During the first year the Austrian Stroke Prevention Study enrolled 599 volunteers without clinical signs or symptoms of cerebrovascular disease aged 50 to 70 years. Study participants were randomly selected from the official register of the city of Graz. The rate of positive response was 26.9 percent. All subjects underwent an extensive risk factor screening with Duplex scanning of the carotid arteries obtained from a subset of 176 individuals. The prevalence of well-documented cerebrovascular risk factors was 40.6% for arterial hypertension, 35.4% for cardiac disease, 8.5% for diabetes mellitus und 3% for elevated haematocrit. The less well-documented cerebrovascular risk factors dyslipidemia, overweight, physical inactivity, hyperfibrinogenemia and smoking were noted in 75%, 33.7%, 27.2%, 14.9% and 12.2% of subjects, respectively. Multiple well-documented risk factors were noted in 23.7% of the examined volunteers. Multiple linear regression analysis revealed body mass index (p < 0.0001) and age (p < 0.0001) as independent predictors of the frequency of well-documented risk factors observed in any individual. Atherosclerotic carotid disease occurred in 61.9% of study participants investigated by Doppler sonography and was significantly associated with age (p < 0.00001), life-time tobacco consumption (p < 0.0001) and the concentration of apolipoprotein B (p < 0.05). This study demonstrates high prevalence rates of vascular risk factors in an elderly Austrian community. Implications for stroke prevention result from the conjunction of overweight and frequency of risk factors noted in any study participant, as well as from the relationship of carotid atherosclerosis to smoking and dyslipidemia.

Aged↗

Validity of skin testing for diagnosis of food allergy in dogs.

One hundred suspected allergic dogs were skin-tested with 9 food extracts, in addition to other inhalant and insect allergens. Forty-eight of the dogs had +2 or greater intradermal reactions to 1 or more food extracts at concentration of 1,000 protein nitrogen units/ml. Thirty of the food extract-positive dogs were fed a restrictive hypoallergenic diet. Of these 30 dogs, 3 improved, then allergy signs worsened when they were challenge-exposed with the original diet. Fifty-two dogs did not have skin test reactivity to any of the 9 food extracts. Of these 52 dogs, 35 were fed a restrictive diet. Six improved, then allergy signs worsened when dogs were challenge-exposed with the original diet. Skin-testing with selected allergenic food extracts was not useful in identifying food-sensitive dogs.

Animal Feed↗

Incidence of systemic reactions during rush immunotherapy.

Rush immunotherapy (RIT) was administered on an outpatient basis to 11 patients. Of these, nine had asthma and four were steroid-dependent. All patients received extracts containing a mixture of antigens to which they were prick-sensitive. FEV1s were greater than 80% predicted before starting RIT. Four patients each required a 1 week steroid "burst" to accomplish this. A series of 8 subcutaneous injections were given starting with 0.3 mL of 1:100,000 (wt/vol) and ending with 0.10 mL of 1:100 (wt/vol) 1.5 days later. A dose of 0.15 mL of 1:100 was given weekly after that. All patients but one completed the RIT. Four had sore arms, four had pruritus and/or sneezing, four developed wheezing, and one experienced anaphylaxis with hypotension. Systemic reactions tended to occur at the higher doses and usually more than 30 minutes after a previous injection. Subsequent weekly injections were tolerated without reactions by seven of the patients. Rush immunotherapy is an effective method for administering a high dose of allergen in a very short time period. Due to the risk of systemic reactions it needs to be given under carefully controlled conditions.

Adolescent↗

Magnetic resonance imaging white matter lesions and cognitive impairment in hypertensive individuals.

To search for a morphologic basis of cognitive impairment possibly associated with essential hypertension, we studied 35 otherwise asymptomatic hypertensive individuals (mean age, 38.7 years; range, 22 to 49 years) and 20 normotensive control subjects (mean age, 37.9 years; range, 26 to 49 years) using neuropsychologic tests and magnetic resonance imaging. Irrespective of drug treatment, hypertensive individuals performed significantly worse than did control subjects when assessed for verbal memory and total learning and memory capacity, while there were no differences in test results of visual memory, attention, vigilance, and reaction time. The hypertensive individuals also described themselves as less active but ranked similar on five other mood subscales. Punctate high-signal intensities of the white matter were found almost twice as often in the hypertensive group (38%) as in the control group (20%). There was no difference in test performance between hypertensive individuals with and those without white matter lesions, however. Our results confirm the presence of subtle neuropsychologic deficits and indicate a higher frequency of white matter signal abnormalities in essential hypertension, as shown on magnetic resonance imaging, but do not indicate a correlation of these findings with each other.

Adult↗

Cerebral hemodynamic changes following treatment with erythropoietin.

Adverse hemorheologic effects induced by erythropoietin (EPO) treatment of renal anemia may pose a cerebrovascular risk. We therefore investigated the changes in cerebral perfusion, cerebral blood flow velocity (BFV) and neuropsychologic performance in 11 patients (mean age 37 years) receiving EPO. In response to EPO there was a significant (p less than 0.01) increase in hematocrit (35%), hemoglobin (43%) and whole-blood viscosity (50% at high and 90% at low shear rate). The initially increased blood flow velocity dropped significantly (p less than 0.05) and returned toward normal values in the middle cerebral arteries and the basilar artery (22 and 19% decrease, respectively). Global cerebral blood flow (CBF) decreased by 10% (not significant). The score of the Wechsler Adult Intelligence Scale digit symbol test improved significantly (p less than 0.01) after EPO treatment. None of the patients developed cerebrovascular symptoms or side effects. We conclude that the hematologic and rheologic changes following EPO treatment cause CBF and BFV to return toward normal and improve neuropsychologic performance in patients with end-stage renal disease.

Adult↗

Gummatous lesions in men infected with human immunodeficiency virus and syphilis.

Two HIV-infected men are reported who developed gummatous lesions more than 12 months after appropriate treatment of presumptive syphilis. In one patient the lesions developed without any change in the VDRL titre. The most likely explanation for these lesions is reactivation of syphilis in the context of HIV infection. As these lesions respond to penicillin, the possible reactivation of appropriately treated syphilis, or even yaws, should now be considered in any ulcerative lesion in HIV infected individuals at risk from treponemal infection.

Adult↗

White matter signal abnormalities in normal individuals: correlation with carotid ultrasonography, cerebral blood flow measurements, and cerebrovascular risk factors.

We studied 52 asymptomatic subjects using magnetic resonance imaging, and we compared age-matched groups (51-70 years old) with and without white matter lesions with respect to carotid ultrasonography, cerebral blood flow (xenon-133 injection), and cerebrovascular risk factors. In the group with white matter signal abnormalities, we noted a higher frequency of extracranial carotid artery disease, a lower mean gray matter blood flow (F1), and a significant reduction (p less than 0.05) in blood flow of the slow-flowing (F2) compartment. Hypertension, diabetes mellitus, and cardiac diseases (p less than 0.002) were found more often in this group. Our results indicate that a higher incidence of changes known to be associated with an increased risk for stroke exists in the presence of white matter lesions in normal elderly individuals.

Adult↗

Criteria for an increased specificity of MRI interpretation in elderly subjects with suspected multiple sclerosis.

We reviewed the MRIs of 49 asymptomatic volunteers (age range, 31 to 77 years) and of 50 MS patients (age range, 14 to 63) for areas of increased signal (AIS) and features discriminating MS lesions from lesions seen with normal aging. We obtained optimal specificity of MRI interpretation (100%) if we required at least two of the following three AIS features--size greater than or equal to 6 mm, abutting ventricular bodies, infratentorial location--for a positive MRI diagnosis of MS. Applying these criteria to the MRIs of elderly patients with suspected MS should significantly improve specificity (p less than 0.001) over current quantitative criteria (at least three AIS greater than or equal to 3 mm) without significantly decreasing sensitivity.

Adolescent↗

Digital tomosynthesis: technique for electronic reconstructive tomography.

A technique is described for obtaining tomographic images through retrospective reconstruction of digital data. The apparatus used for this technique, called digital tomosynthesis consists of a linear tomographic x-ray machine that has been modified by the addition of a fluoroscope and TV system, a video disk recorder, an analog-to-digital converter, and a small computer for data processing and manipulation. Video frames are collected and stored during a single tomographic sweep. The stored data are then digitized and retrospectively processed in the computer for reconstruction of any desired tomographic plane within the body. The major advantages of DTS include short patient study time, low radiation dose compared with conventional tomography, the ability to enhance the digitized image through manipulation of window and level display, and the applicability of this technique to dynamic studies such as angiotomography. Phantom studies show good diagnostic quality of the resulting images, and preliminary vascular studies in dogs indicate the clinical potential of this technique for use in digital subtraction angiotomography.

Animals↗

Issues in pediatric research: safeguarding the children.

PURPOSE: To address the ethical question: "How can one safeguard children who participate in research?" PATIENT POPULATION: Infants through adolescents. CONCLUSIONS: Federal guidelines that delineate when research is allowable with children may not be enough to ensure children's safety from harm. PRACTICE IMPLICATIONS: Risk evaluation conducted by those who understand child development because such understanding allows one to better anticipate children's potential exposure to harm. Safeguarding children requires a conscientious effort to envision children's understanding of events, their potential reactions, and the possible immediate and long-term consequences. This understanding provides the foundation for implementing sound research procedures to safeguard the children.

Adolescent↗

Clinical application of digital tomosynthesis: a preliminary report.

Digital tomosynthesis represents a new technique for digital manipulation of data acquired during a single tomographic sweep. With the aid of a computer, data can be processed to yield images in any parallel plane of the body. This technique allows rapid tomographic studies requiring a much lower radiation dose to the patient. Dynamic studies such as angiotomography are feasible, and application to digital subtraction intravenous angiography is also possible with this technique. Early experience with clinical application in patient studies is presented.

Adult↗