The American journal of medical technology最新文献

Multiple sclerosis (MS) is a relatively common cause of inflammatory demyelinating lesions of the central nervous system. In an attempt to detect and characterize ongoing demyelination in MS patient brains, we used a novel magnetic resonance imaging (MRI) technique, involving the fitting of a three-component model to the [Formula: see text] relaxation behavior at high-field (7 T). This model allowed estimation of the amount of myelin water (and thus indirectly myelin content), axonal water, and interstitial water. In this study, 25 relapsing-remitting MS patients underwent a 7 T MRI from which 12 gadolinium-enhancing lesions, 61 non-enhancing lesions, and their corresponding contralateral normal appearing white matter (NAWM) regions were analyzed. In both enhancing and non-enhancing lesions, the amplitude of myelin water was significantly decreased, and interstitial and axonal water were increased relative to the contralateral NAWM. Longer relaxation time [Formula: see text] of interstitial and axonal water, and lower frequency shift of axonal water, were also observed in both enhancing and non-enhancing lesions when compared to the contralateral NAWM. No significant difference was found between enhancing lesions and non-enhancing lesions. These findings suggest that the fitting of a three-component model to the [Formula: see text] decay curve in MS lesions may help to quantify myelin loss.

Biological variation (BV) in diagnostic tests can be conveniently estimated by the equation, BV = magnitude of reference limit - reference median magnitude of - 2(SD)A, where "reference limit" refers to either the 2.5th or 97.5th percentile in the reference population, magnitude of indicates absolute value, and (SD)A is the standard deviation of random analytical variation at the reference median. The value of (SD)A is calculated from the equation, (SD)A = (CV)A (reference median)/100, where (CV)A, the coefficient of variation of random analytical variation, is obtained from routine stable quality control material. The BV was calculated for plasma glucose concentration at the time points in the oral glucose tolerance test in an asymptomatic reference population and found to vary in the order: fasting less than 3 hour less than 1/2 hour less than 1 hour less than 2 hour. We present correlation coefficients between subject age and plasma glucose concentration that suggest that BV at the fasting, 1/2, 1, and 2 hour points might be reduced by subdividing reference populations according to subject age.

A monodispersed band is a dense, homogeneous band on serum protein electrophoresis (SPE), indicating the presence of a discrete protein. Minor monodispersed bands in the gamma region on SPE usually indicate minor monoclonal immunoglobulins that can be characterized by immunofixation. Occasionally, these minor monodispersed bands cannot be shown to be immunoglobulins. This report illustrates that elevated levels of C-reactive protein (CRP) may be detectable as an "M-spike" on SPE; therefore, if immunofixation is performed, anti-CRP could be included in the panel of antisera used to characterize the minor monodispersed band. The detection of CRP as an "M-spike" in the gamma region is, however, dependent upon the absence of a chelating agent in the SPE support medium. When EDTA is present, the electrophoretic mobility of CRP is altered to a beta mobility.

It appears the state of the art of evaluating factors VIII and IX is in its infancy. With the exception of the screening tests, the more specific methodologies are expensive, time-consuming, and require a certain amount of technical proficiency for proper performance. However, our ability to evaluate these molecules has advanced greatly since the early 1970s. Most probably the methods described in this paper will be available in the near future to all laboratories wishing to perform them, either in kit form or in a more simplified version. Meanwhile, the APTT, mixing tests, qualitative factor assays, and bleeding times may be performed by nearly any laboratory. The performance of these tests will help identify those patients who may have potentially life-threatening postoperative bleeding episodes or who are having a bleeding episode that requires diagnosis for effective treatment. It is therefore important that these tests be incorporated into our routine coagulation protocols.

Simple and rapid Bactec methodologies for the determination of neat (unaltered) and heat stable urease activity of mycobacteria are presented. Clinical isolates (63) and stock cultures (32)--consisting of: M. tuberculosis (19), M. bovis (5), M. kansasii (15), M. marinum (4), M. simiae (3), M. scrofulaceum (16), M. gordonae (6), M. szulgai (6), M. flavescens (1), M. gastri (1), M. intracellulare (6), M. fortuitum-chelonei complex (12), and M. smegmatis (1)--were tested for neat urease activity by Bactec radiometry. Mycobacterial isolates (50-100 mg wet weight) were incubated at 35 degrees C for 30 minutes with microCi14C-urea. Urease-positive mycobacteria gave Bactec growth index (GI) values greater than 100 units, whereas urease-negative species gave values less than 10 GI units. Eighty-three isolates possessing neat urease activity were heated at 80 degrees C for 30 minutes followed by incubation at 35 degrees C for 30 minutes with 1 microCi14C-urea. Mycobacterium tuberculosis-bovis complex demonstrated heat-stable urease activity (GI more than 130 units) and could be distinguished from mycobacteria other than tuberculosis (MOTT), which gave GI values equal to or less than 40 units.

A course has been devised to simulate a hospital stat lab environment for students in a 2-year MLT Associate Degree program. This course ensures that each student will individually perform a wide variety of laboratory procedures and report results under hospital-like circumstances. This course, which has received favorable comment from NAACLS, circumvents problems of insufficient placement situations, inadequate supervision, and limited variety of student experience in hospital sites. Course procedures, objectives, and student evaluation methods are described.