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Two promising methods of assessing the removal of blood microaggregates or other particulates from stored blood by microfilters, namely electronic particle size distribution analysis and screen filtration pressure (SFP) measurements, were compared. Microaggregate counts and size distributions have been difficult to quantitate because of a lack of reproducibility of the measurements. This problem has now been largely eliminated by the use of a red cell lysing solution containing hexadecyltrimethyl-ammonium bromide (CTAB), acetic acid and glutaraldehyde which permits destruction of the red cells yet stabilizes the microaggregate counts. As a consequence it has been possible to make a quantitative comparison with the screen filtration pressure method. The correlation between the SFP values obtained with screens having pore sizes of 20 × 20, 30 × 30, and 40 × 40 μand the number of microaggregates measured electronically has been examined for outdated blood bank blood. The 30 μscreen was found to offer advantages over the 20 and 40 μm screens. Samples containing different relative concentrations of microaggregates were prepared by mixing various proportions of repeatedly filtered and unfiltered blood such that the maximum SFP was ⩽ 450 mm Hg using the 30 μscreen. When SFPs > 250 mm Hg were extrapolated from the straight line trace between ∼ 20 to 250 mm Hg, it was shown that the SFP values were linearly related to the relative quantity of filtrable material. A linear relationship was also observed between the relative quantity of microaggregates and the particles counted electronically. The simplicity and reproducibility of the SFP procedure offer advantages over electronic particle size distribution analysis for the evaluation of the performance of blood microfilters.

• Patients with multiple sclerosis (MS) have been shown to have a measurable deterioration in the ability to perceive temporal variations of light. Compared to the traditional critical flicker fusion (CFF) measure, a modified flicker fusion test showed an improved sensitivity for denoting neurological deficit in temporal vision. One hundred twenty-two patients with MS were examined. The traditional CFF test exhibited abnormalities in 48%; the modified test exhibited abnormalities in 78% of the same patients. These results appear to be independent of whether or not the demyelinating disease clinically involved the visual system. Also, the percentage of abnormalities demonstrated by combining both techniques was unexpectedly high (60% to 80%) in patients with minimal evidence of neurological involvement.

The difficulties of linking physiological changes in people with weather factors are great. They are increased manyfold when the study is limited to the macroclimate of the approximate geographic environs of a person or group of persons, since the physiological interactions are with the microclimate in immediate contact with the person, rather than with the geographic weather. The macroclimate is considerably modified by factors such as buildings, clothing, activity, etc.The influence of weather on multiple sclerosis has been the subject of frequent discussions. Many writers have expressed the thought that the disease is influenced by climate factors, and Ziegler1 reported that exacerbations of the disease in Minnesota occurred most frequently in the spring. Limburg2 was unable to find statistical evidence to support this contention but felt that his studies supported previous observations that the disease is more frequent in colder climates. He suggested, on the basis of

The primary purpose of this paper is to report the results of five and one-half years' experience of treating multiple sclerosis with a low-fat diet. A preliminary report of this method of treatment on the same patients was made two years ago.1 At that time it was reported that during an average treatment period of nearly three years 45 patients with exacerbating-remitting type of multiple sclerosis seemed to benefit from the low-fat diet. This tentative assumption was based on a reduction in the frequency and severity of exacerbation of the disease and upon an increased performance of patients on the low-fat diet. The earlier cases seemed to benefit more than those with established disabilities. At that time possible theoretical reasons for employing the low-fat diet were discussed, and papers by me in collaboration with other investigators * bearing on our problem were reviewed in detail.The secondary purpose of the

The scalenus anticus syndrome has occurred with unexpected frequency in members of the armed forces of the United States. Its incidence has been sufficiently great to warrant emphasis on the ease with which the syndrome can be recognized and treated. Furthermore, certain observations of both clinical and physiologic importance should be recorded.Characteristic neurologic signs, consisting of sensory changes, muscular spasm and weakness, were noted among the patients studied. The distribution and nature of these signs, together with their response to appropriate therapy, suggest that they were due to compression of cervical nerve roots. The mechanism by which the lower roots are compressed by the scalenus anticus muscle is fairly well understood, but the means by which the upper roots are compressed needs to be clarified. In an attempt to do this, a detailed anatomic account of the scalene muscles and their pertinent relations will be presented.For a review

In an earlier paper Swank and Engel1 showed that most hamsters fed large cream fat meals developed convulsions. The seizures first appeared about 3 hours after feeding. They were first focal. Later they became generalized. Many of the animals which developed generalized seizures did not survive. After feedings of equally large meals of vegetable oil, only an occasional focal, or no seizures were seen.The purpose of this paper is to explore more completely the relationship of different triglycerides to the occurrence of the seizures and to report the changes in the electroencephalograms and in available cerebral oxygen which accompany the seizures. MATERIALS AND METHODS Golden hamsters weighing 60 to 100 gm. were used as the experimental animal. Naturally occurring fats and oils and mixtures of synthetic and naturally occurring triglycerides were fed by stomach tube while the animals were under very light ether anesthesia.* Electroencephalograms were made by

IN A PREVIOUS investigation Swank, Franklin, and Quastel1 found that the plasma protein pattern in paper chromatograms may be abnormal during exacerbations of multiple sclerosis. During remission the plasma protein pattern returns to normal. Using the ultracentrifuge, Aird, Gofman, Jones, Campbell, and Garoutte2 observed the presence of abnormal plasma lipoprotein fractions during activity of the disease. The fact that these abnormal lipoproteins occurred during exacerbations suggests that they are in some way related to the previous observation of Swank, Franklin, and Quastel.1 However, no decision is yet justified.The purpose of the present paper is to demonstrate the normal paper chromatogram and its changes when studied frequently over long periods of time in normal human subjects, and in patients with multiple sclerosis during periods both of activity and of relative inactivity of the disease. MATERIAL AND METHODS Blood samples were obtained from fasting patients and fasting normal

IN TWO previous papers the hypothesis has been developed that the geographic variations in the incidence of multiple sclerosis are influenced by the average amount of the fat consumed: A high-fat consumption is associated with a high incidence of multiple sclerosis; a low-fat consumption is associated with a low incidence of multiple sclerosis.1 Evidence has also been presented which suggests that the consumption of relatively saturated milk and animal fats is more likely to be associated with a high incidence of multiple sclerosis than is the consumption of unsaturated vegetable and fish oils. In either event fat intake seems to increase the incidence of multiple sclerosis by precipitating the disease in susceptible persons.With the information at hand it is not possible to prove that the apparent relationship of high-fat consumption to a high incidence of multiple sclerosis is not due to factors other than fat which have the

IN World War II the neuroses which result from combat have been designated as "combat exhaustion." This terminology implies two fundamental things: First, these neuroses are due primarily to combat, and, second, they develop after a period of combat sufficiently long to produce a significant degree of exhaustion.1 Through misunderstanding many people use the term indiscriminately, and confusion has arisen; they include under this head the neuroses which develop during the first few days of combat, and even the disorders of behavior of men who have never experienced actual combat. The usefulness of this term in distinguishing the more stable and willing from the unstable and unwilling personalities is thereby lost. This is unfortunate, since a substantial percentage of men are of the former type and have broken down under conditions of continuous long and severe stress which infrequently, if ever, obtained before. The number of early breakdowns has

In acutely thiamine-deficient pigeons marked impairment of function of the central nervous system develops, associated with a characteristic and progressive series of head and neck movements and degeneration of certain neurons (Swank1; Swank and Bessey2; Swank and Prados3). The first of these movements consists of rhythmic lateral rotation of the head alone or combined with extensor thrusts of the neck and has been designated preopisthotonos. This phase may last from a few to twenty-four hours and in progressive thiamine deficiency is followed by complete opisthotonos. If the deficiency is allowed to become more severe, and death does not intervene, opisthotonos is followed by slow relaxation; the pigeon can no longer elevate its head above the horizontal and is generally listless. This final stage, enopisthotonos, is followed by death within a few hours if thiamine is not administered.Histologic studies (Swank1; Swank and Prados3) have revealed

Knowledge of the pyramidal system is incomplete and confused because too much reliance has been placed on study of normal histologic material rather than on critical experimental methods. This is especially true of the rabbit. According to Linowiecki,1 the pyramidal tract of the rabbit is located in the lateral funiculus of the spinal cord. His conclusion was based on work of Lenhossék,2 Bechterew3 and Münzer and Wiener4 and was strengthened not by experiments but by his own study of normal material. Lenhossék's and Bechterew's sections stained with the Weigert method from normal new-born rabbits exhibited an area in the dorsal part of the lateral funiculus from which myelin was absent, and the authors assumed this area to be in the position of the corticospinal tract.Münzer and Wiener employed both normal histologic preparations and degenerating postoperative material stained by the Marchi technic. On the basis of

The effects of changes in association, flexibility and electrokinetic charge of red blood cells on the flow properties of their suspensions were studied using the screen filtration pressure (SFP) method and cone-plate viscometry. The SFP is dependent mainly on aggregation and adhesiveness of the cells; the volume concentration of the cells and viscosity of the plasma playing less important roles. The viscosity at moderate rates of shear depends on the volume concentration of the cells whilst aggregation and adhesiveness play a minor role. Decreasing the electrokinetic charge of the red cells by treatment with neuraminidase or uranyl nitrate, or prehardening the cells with acetaldehyde produce no significant change in the cone-plate measurements for rates of shear >11.5 sec−1at volume concentrations <45 per cent. At volume concentrations >50 per cent the “viscosity” of the suspensions of prehardened cells increases much more rapidly with volume concentration than for normal red cell suspensions.