Measurement of the neutron magnetic form factor from inclusive quasielastic scattering of polarized electrons from polarized 3He.
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Journal Article↗
Biomedical subjects
J Arrington
Publications and source records attributed to J Arrington.
Purpura as the presenting sign of an internal disease. Multiple myeloma.
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Aged↗
Brain magnetic resonance imaging in acute optic neuritis. Experience of the Optic Neuritis Study Group.
OBJECTIVE: Changes in the brain on magnetic resonance images are common in patients with optic neuritis even when there is no other clinical evidence of multiple sclerosis. The current study was designed to determine systematically the prevalence of brain abnormalities on magnetic resonance images in the patients entered into the Optic Neuritis Treatment Trial. DESIGN: Prospective multicenter clinical trial. SETTING: Referral centers. PATIENTS AND METHODS: Brain magnetic resonance images from 418 patients with acute optic neuritis (77% women; mean age, 32.0 years) were evaluated at a central reading center with the use of a standardized classification system (ranging from 0 for normal to IV for most extensive changes). RESULTS: Of the scans, 40.9% were classified as grade 0, 10.8% as grade I, 9.1% as grade II, 6.7% as grade III, and 32.5% as grade IV. For patients with isolated (monosymptomatic) optic neuritis, 26.7% had two or more lesions. CONCLUSIONS: We found a lower prevalence of brain magnetic resonance imaging abnormalities in isolated optic neuritis than previous studies have reported. This likely is due to our study having a higher degree of standardization of patient inclusion criteria, which limited patient selection bias.
Acute Disease↗
Papular dermatitis in adults: subacute prurigo, American style?
Determining the best treatment for recurrent pruritic papular eruptions that do not fit well into a diagnosis (of either atopy or some other diagnosis) is sometimes frustrating. We have studied 12 patients with recurrent pruritic papular eruptions by obtaining extensive histories and by performing skin biopsies, immunofluorescence studies, and screening patch tests. The eruptions in this group are not atopic by strict criteria but have atopic features and are without a determinable exogenous cause. Histologic features resemble papular urticaria, but there is no history to suggest arthropod bites. Patients with this type of eruption have features similar to those with subacute prurigo, and they respond to variable combinations of topical or systemic corticosteroids, systemic antihistamines, and UVB or UVA. We suggest that the designation of subacute prurigo might be more appropriate for patients with these findings.
Acute Disease↗
Placental histology in fetuses between 18 and 23 weeks' gestation with abnormal karyotype.
Placentas from karyotypically abnormal fetuses (18 to 23 weeks' gestation) were analyzed prospectively at the light microscopic level. Group I consisted of 14 control placentas. Group II consisted of 14 placentas from fetuses with an abnormal karyotype. Secondary and tertiary stem villi counts, small muscular artery counts, and total vessel counts were determined per 100 x field. There were no differences in secondary and tertiary stem villi counts between groups. A significant decrease in small muscular artery counts (p less than 0.01) and total vessel counts (p less than 0.01) was noted in group II. Placental and fetal weights were comparable between groups. This undervascularization may represent placental immaturity as a result of arrested or delayed angiopoiesis. It appears that this abnormality is established before the third trimester and may be enhanced by late vascular obliteration as reported by others. These data substantiate the concept that the structure and function of the placenta is determined to a great degree by fetal karyotype and may help explain the morbidity and mortality seen in these fetuses.
Chorionic Villi↗
Doppler study of umbilical artery blood flow waveform. Should we use an instrument-adapted nomogram?
Doppler studies of umbilical artery blood flow waveform are becoming an accepted tool of antenatal estimation of fetal well-being. The S/D ratio of the systolic peak (S) to the end-diastolic (D) frequency is the most commonly used parameter. Nomograms relating S/D ratio to gestational age have been published both for normal and pathologic pregnancies. Three hundred twelve analyses of umbilical artery blood flow were performed by continuous Doppler technology in normal, well-dated pregnancies using either one of the following instruments: GE 3600 (GE) or Multigon 500A (MG). Both instruments showed a decrease of S/D with GA, but, by use of a nonpaired t test, a statistically significant difference was found between the two machines. Data on the system used for a particular study should be provided; nomograms for this particular instrument should be consulted and the same machine should be employed for repeat testing in longitudinal studies.
Blood Flow Velocity↗
Doppler analysis of the umbilical artery. The importance of choosing the placental end of the cord.
Thirty normal pregnancies were studied with continuous or pulsed Doppler ultrasound (50 measurements). The ratio of systolic (S) to end-diastolic (D) measurement, or S/D ratio, was obtained at both ends of the cord: the placental insertion and the fetal abdominal insertion. A statistically significant difference was demonstrated between the two sets of measurements. Normal values were obtained at the placental insertion, whereas, simultaneously, the fetal abdominal insertion generated highly abnormal values. When performing Doppler waveform analysis of the umbilical artery, if abnormal values are obtained, one should be cautious to be certain that they originated from the placental insertion.
Blood Flow Velocity↗
Magnetic resonance angiography of vascular lesions causing neuro-ophthalmic deficits.
Magnetic resonance angiography (MRA) is a noninvasive, rapidly evolving technique for imaging the intra- and extracranial carotid and vertebrobasilar circulations. It may in some circumstances obviate conventional angiography and the accompanying risks associated with catheterization and contrast injection. MRA exploits the different physical properties between moving protons and stationary tissue to yield flow sensitive data in the form of anatomic images or velocity and flow measurements. Since patients with various vascular disorders may present exclusively with ophthalmologic signs and symptoms, it is expected that MRA will become more frequently utilized by ophthalmologists. The exact role of MRA in the workup of vascular disorders remains to be more precisely defined, pending the performance of additional well-controlled standardized studies. At present, MRA is utilized to complement the conventional spin-echo studies of patients with arterial and venous occlusion, vascular malformations, intracranial aneurysms, and neoplastic vascular invasion. With further refinements, it is expected that MRA will become a standard diagnostic tool for the evaluation of patients with vascular disorders.
Blood Flow Velocity↗