Plaque causing homonymous hemianopsia in multiple sclerosis identified by computed tomography

Three patients with multiple sclerosis (women 20, 24, and 30 years old) had demyelinative plaques that produced homonymous hemianopsia. These lesions were identified by computed tomography which showed the plaques as hypodense areas. All patients with homonymous hemianopsia should undergo computed tomography; if a hypodense or enhancing lesion is identified, the diagnosis of multiple sclerosis must be considered.

Placental amino acid uptake. VI. Regulation by intracellular substrate

Amino acid uptake by human placental tissue is regulated by intracellular amino acids. alpha-Aminoisobutyric acid (AIB) uptake was reduced at intracellular AIB concentrations of 0.8 mM. The magnitude of reduction increased sharply between 1 and 3 mM and reached a maximum of 45% at 5 mM. Suppression was specific to the "A" system. It occurred only when both the amino acid used for preloading and that used as an uptake substrate were active with that system. In the "L" system, facilitation apparently occurs, and in the "ASC" system there is no apparent effect. The system specificity as well as other evidence indicated that suppression is caused by substrate present intracellularly rather than by dilution of extracellular substrate. Suppression was independent of inhibitors of protein synthesis and was not seen in membrane vesicles prepared from preloaded tissue, indicating that intracellular substrate interacts directly with the carrier (transinhibition) rather than altering its synthesis or degradation. The A system transinhibition has the potential to regulate syncytial uptake in vivo and limit variation due to changes in maternal plasma amino acid concentration.

Carotid sinus reflex in patients undergoing coronary angiography: relationship of degree and location of coronary artery disease to response to carotid sinus massage

Heart rate and blood pressure responses during and after carotid sinus massage were examined in 66 patients just before coronary angiography. A significant relationship was found between heart rate and blood pressure responses and (1) angina pectoris class, (2) total coronary artery disease score and (3) presence of high-grade (> 90%) stenosis of any of the three major coronary arteries. Only patients with contraction abnormalities of the anterolateral left ventricular region had greater cardionhibitory responses than patients with normal left ventricular angiograms. Among patients with normal left ventricular angiograms, those with more than 50% stenosis of one or more vessels had significantly (p < 0.01) greater responses than those with no or minimal coronary artery disease. All 21 hypersensitive (asystole longer than 3 seconds) patients had significant multivessel coronary artery stenoses or single-vessel high-grade stenosis (greater than or equal to 90%) proximal to the atrioventricular nodal artery. None of the 11 patients with normal coronary arteries had an exaggerated response to carotid sinus massage. These data support the association of an exaggerated response to carotid sinus massage in the presence of symptomatic coronary artery disease and suggest that the magnitude of response is influenced by the severity of the disease.

Presenile Alzheimer disease: amyloid plaques in the cerebellum

Seven of 24 patients with pathologically proved Alzheimer disease had amyloid plaques resembling kuru plaques in the cerebellum. In all seven patients, the dementia was presenile in onset, there was a positive family history of the disease in five patients, and other neurologic symptoms were present in five. Similar plaques have been described in one of two patients with familial Alzheimer disease from whom spongiform encephalopathy was induced in subhuman primates after intracerebral inoculation of brain tissue. These observations suggest that some cases of familial Alzheimer disease may be clinically distinct from senile dementia and may not be genetic in origin.

Emit assays for five major anticonvulsant drugs. An evaluation of adaptations to two discrete kinetic analyzers

Because of the complex reaction kinetics observed with the enzyme multiplied immunoassay technic (EMIT), each adaptation of these assays must be specifically evaluated. Evaluations were done of the totally automated adaptations of these immunoassays for diphenylhydantoin, phenobarbital, primidone, carbamazepine, and ethosuximide to two kinetic analyzers that use markedly different reaction conditions, the Gilford System 3500 and the Abbott Bichromatic Analyzer-100. Comparisons of data from EMIT assays on the Gilford 3500 with data from EMIT assays on the ABA-100 and with data from gas-liquid chromatographic analyses for the five anticonvulsant drugs showed good correlations (r greater than or equal to 0.96) and little or no additive or proportional biases, as determined by joint confidence intervals. Between-run precision for each EMIT anticonvulsant drug assay on both analyzers was less than 6%, better than that obtained with gas chromatography. No interference by more than 40 different drugs, by hemoglobin (6 g/l), or by bilirubin (200 mg/l), and no or minimal cross-reactivity with any of the five EMIT anticonvulsant drug assays on either analyzer were found.

Interrelationship of dietary ascorbic acid and iron on the tissue distribution of ascorbic acid, iron and copper in female guinea pigs

Female guinea pigs were fed diets varied in ascorbic acid and iron concentration for 21 days. Tissue concentrations of ascorbic acid, iron (total, ferritin and hemosiderin) and copper were determined in blood, liver and spleen. High dietary ascorbic acid (10 times control) increased tissue ascorbic acid levels and produced a decrease in liver ferritin and hemosiderin, without altering liver or plasma total iron. Conversely, splenic total iron increased with no changes in ferritin and hemosiderin iron. The increased ascorbic acid did lower copper levels in blood and liver, 39% and 52%, respectively. In guinea pigs maintained on an ascorbic acid-free diet for 21 days, a decrease in hepatic ferritin and total iron was observed, as well as an increase in splenic hemosiderin and total iron. No change in plasma iron was observed nor were any of the copper pools altered. Intake of high dietary iron (10 times control) increased hepatic iron stores and produced a reciprocal decrease in hepatic copper. Even though splenic iron increased, no significant change in copper resulted. The significance of these nutrient interactions is discussed.

Placental amino acid uptake. V. Relationship to placental maturation in the rat

The functional maturation of the placenta during the latter portion of pregnancy is almost certainly essential to fetal growth but its mechanism is largely unknown. To determine the role of changes in intrinsic cellular transport in this process we measured the activity of transport systems for AIB between day 14 and term, a period of known marked increase in in vivo AIB transfer in the rat. In vitro incubation demonstrated that the labyrinthine tissue possessed two transport systems for cellular AIB uptake. Their maximum velocities remained essentially constant from day 16 to term and the intracellular concentration achieved during incubation actually decreased with gestational and the intracellular concentration achieved during incubation actually decreased with gestational age. In vitro tissue preincubation increased cellular uptake of AIB and this response also decreased with maturation. Thus changes in intrinsic transport mechanisms do not at all parallel the very large maturational increase in in utero amino acid transfer. Changes in intrauterine factors such as blood flow, the hormonal millieu, or fetal utilization and the resultant placental-fetal concentration gradients are much more likely to account for the increase in transfer than are alterations in cellular transport mechanisms.

Transferrin receptors on the human placental microvillous membrane

A preparation of microvillous membrane vesicles from human placental syncytiotrophoblast binds transferrin to specific transferrin receptors. Transferrin binding to placental receptors is rapid, saturable, reversible, and specific. Approximately 2.5 X 10(13) receptors are present per milligram of membrane protein; the apparent association constant of transferrin for the placental receptor is 2.2 X 10(7) X M-1. No evidence for removal of iron from transferrin bound to intact membrane receptors was observed in these studies. Nonionic detergent solubilization and partial purification of the microvillous membrane transferrin receptor were carried out with preservation of the functional properties of the receptor.

Monosaccharide transport across microvillous membrane of human placenta

Transport through the microvillous membrane of the syncytium is the first step in placental transfer of nutrients. We have therefore studied glucose transport by isolated microvillous membrane vesicles. Transport occurred by selective and rapid facilitated diffusion, which was inhibited by phloridzin, phloretin, cytochalasin B, and HgCl2. Nonmediated diffusion of the substrate was found by three independent methods to be very slow. Competition studies showed that aldohexoses in the C-1 chair conformation were the preferred substrates. Transport was independent of sodium gradients and was not modulated by insulin. However, several steroids inhibited transport including estriol and progesterone, which are abundant in utero. Kinetic analysis by equilibrium exchange demonstrated a Km of 31 mM and a Vmax of 120 nmol . s-1 . mg protein-1. The Km and Vmax suggest a large capacity in relation to calculated fetal needs. In consequence of this capacity, intrasyncytial concentrations of glucose are probably maintained near those of maternal blood. Augmentation of transport at this membrane by hormones or other agents is unlikely to increase fetal supply of glucose, but down regulation by steroids may serve a regulatory function.

Adaptation of the EMIT theophylline assay to kinetic analyzers: the relationship of reaction kinetics to calculation procedures

We investigated the kinetic characteristics of an enzyme immunoassay system (EMIT) for the determination of theophylline. Less than 10% of the glucose-6-phosphate and NAD+ are consumed and the glucose-6-P-dehydrogenase-theophylline complex is essentially saturated with these substrates during the course of the reaction. However, apparently as the result of antibody heterogeneity, the rate does change during the course of the reaction. As a result, the values of the kinetic parameters for the theophylline saturation curve vary with the timing interval chosen for measurement. We show that the values of these parameters govern the application of the available methods of calculating EMIT data, the graphical procedure suggested by the manufacturer, logit-log, log-log, and curve fitting. These studies (1) explain the basis of the graphical procedure and why it does not always provide proper calibration, (2) show that to appropriately understand the application of any of the calculation procedures one should determine the values of the kinetic constants of the theophylline saturation curve in the particular assay conditions, and (3) illustrate simple, practical procedures for determining the values of these constants for any instrument-EMIT assay system. Specific illustrations are shown for the EMIT theophylline system with two kinetic analyzers, the Abbott ABA-100 and Gilford 3500, with which markedly different reaction conditions are used.

Integrating the teaching of sickle cell anemia into the curriculum of the Cincinnati public school system

In an effort to determine the impact of one aspect of the Cincinnati Comprehensive Sickle Cell Center's educational program, a study of the level of knowledge of sickle cell facts by elementary and secondary school students in the Cincinnati public school system was conducted. An underlying assumption of this study was that a specially adapted sickle cell teaching curriculum in conjunction with in-service training for science teachers by sickle cell education staff was effective and practical. The study provided support for this assumption and has important implications for educating the general public about sickle cell disease and sickle cell trait. This study was undertaken during the 1975-1976 school year, and has subsequently led to the adoption of this sickle cell teaching curriculum by the Cincinnati Board of Education.

A clinically applicable high-pressure liquid chromatographic method for measurement of serum theophylline, with detailed evaluation of interferences

A high-pressure liquid chromatographic method for the routine measurement of serum theophylline that is accurate, specific, and sensitive is presented. It is technically simple, requires only 50 microliter serum, and takes relatively little technician time. Values for theophylline in sera obtained by this method correlate well with those obtained by use of a gas-liquid chromatographic method (r = 0.980) and with values obtained by the commonly used spectrophotometric method (r = 0.939) when the latter is free of interference. The assay has been employed for two years in a routine clinical chemistry laboratory, with interassay coefficients of variation of 2.4-3.2%. Interferences have been identified at an incidence rate of 3.8% of all specimens, and interfering substances include cephazolin, chloramphenicol, sulfamethoxazole, and sulfisoxazole. A calculation technic that allows a reliable and clinically useful estimation of a range of concentrations of theophylline in the serum when these interferences are present is described. In contrast, the incidence of interferences with the spectrophotometric method is 4.9%, and in this method the interferences prevent the analysis of theophylline. Of 33 samples having interferences by use of the spectrophotometric method, the high-pressure liquid chromatographic technic yielded precise values for theophylline in 21 and reliable estimates of ranges of concentrations of theophylline in the remaining 12.

Insulin and placenta: degradation and stabilization, binding to microvillous membrane receptors, and amino acid uptake

Human placenta possesses insulin receptors, yet whether insulin affects uptake of substrate or other placental functions is still controversial. A potential problem in the study of this issue is degradation of insulin by placental tissue. We found insulin degradation to be rapid and temperature dependent. At 10 mU/ml and 37 degrees C, 40% became trichloroacetic acid soluble within 15 minutes. Degradation was decreased by preincubation of tissue, followed by change of medium and by addition of 0.5% to 2.0% bovine albumin. Receptor assay with isolated microvillous membrane, which bound insulin with the characteristics of known target tissues, demonstrated biologically active insulin (5 to 6 mU/ml) to persist under incubation conditions. The presence of insulin did not influence the uptake of amino acids by the three neutral amino acid transport systems of the human placenta. Thus the transport of an essential fetal nutrient is is apparently independent of fluctuations in maternal insulin with dietary carbohydrate intake and disease.

Assay of theophylline: comparison of EMIT on the ABA-100 to HPLC, GLC and UV procedures, with detailed evaluation of interferences

The EMIT technique for theophylline measurement as adapted to the Abbott Bichromatic Analyzer (ABA-100), was compared to two other established procedures. EMIT results correlated well with those obtained with high pressure liquid chromatographic (HPLC) (r = 0.995, N = 54) and spectrophotometric (UV) (r = 0.95, N = 37) methods when the patient samples used were free of apparent interferences in the comparison methods. On samples exhibiting interferences with HPLC and/or UV methods, the EMIT assay gave the same results as a gas-liquid chromatographic procedure which showed no interferences. In addition, theophylline metabolites, xanthine analogs and many commonly administered drugs did not interfere with the EMIT theophylline assay. An interassay coefficient of variation of 3.5--6.5% was demonstrated. Our data indicate that the EMIT technique exhibits adequate precision and specificity for routine theophylline determinations. Unlike the HPLC or UV procedures, we have not encountered any interferences with the EMIT technique.

Placental amino acid uptake. IV. Transport microvillous membrane vesicles

The recent characterization of a vesicular microvillous plasma membrane preparation from human placenta has made possible study of the characteristics of amino acid transport by the isolated membrane. Variation of medium osmolality demonstrated that alpha-aminoisobutyric acid (AIB) is taken up virtually entirely into a vesicular space. Vesicular volume was determined from equilibrium uptake of three dissimilar nonamino acid substrates, all of which gave a common value. Temperature dependence, saturability, specificity, and similarity of kinetic constants all indicated that AIB uptake by the vesicles resembles that by whole villous tissue. AIB uptake was stimulated specifically by an inward sodium gradient and unaffected by an outward potassium gradient. The persistence of stimulation up to 2 h after the gradient was established could be correlated with the slow equilibration of sodium across the membrane. AIB exodus could be studied with minimal problems of substrate recapture by using preloaded membrane vesicles bound tightly to cellulose ester filters to facilitate transfer to fresh medium. The exodus process was saturable with a Km considerably greater than that for entry.

Characterization of a microvillous membrane preparation from human placental syncytiotrophoblast: a morphologic, biochemical, and physiologic, study

The syncytiotrophoblast microvillous membrane must play a vital role in many essential functions of the placenta. In order to better understand the functional characteristics of this membrane, we have investigated an isolated membrane preparation by a variety of techniques. Electron microscopic observations showed membranous structures similar to microvilli of intact placental villi in size, shape, and microfilamentous content. Similarities in colloidal iron staining and transferrin localization were also shown. The preparation was enriched in enzymes characteristic of surface membranes and diminished in enzymes characteristic of intracellular organelles. Sialic acid content was also increased. SDS gel electrophoresis revealed the presence of a 45,000 molecular weight band, which may be actin. The preparation transported serine, glycine, and alpha-aminoisobutyric acid by a temperature-dependent, saturable process.

Microscale modification of a cation-exchange column procedure for plasma ammonia

A column cation-exchange resin procedure for plasma ammonia was modified to require only 100 mul of plasma per determination. Mean analytical recovery of standard from resin (six samples) was 98% (range, 94-100%) as compared to a mean of 63% (range, 58-70) for nine samples when a batch cation-exchange procedure was used. Absorbance was proportional to sample concentration up to 800 mumol/liter. Analytical recovery of standard from plsma (six samples) was complete (mean, 103%; range, 90-113). Thirteen aliquots of a specimen of fresh plasma from a single adult individual gave a mean value of 20 mumol/liter (range, 11-26). The mean plasma venous ammonia concentration for 27 adults was 16 mumol/liter (range, 0-39), and for 15 newborns it was 60 (range, 34-102). Values for capillary plasma measured at the same time were higher, and we discuss possible explanations for this. Values are given for infants and children from one month to 14 years of age. Effects of storage time and temperature on plasma ammonia concentration are discussed.

Stabilization of blood glucose by cooling with ice: an effective procedure for preservation of samples from adults and newborns

Glycolysis causes a considerable decrease in blood glucose when whole blood is kept at room temperature without preservative. The most commonly used preservative, NaF, makes analysis of other serum constituents such as sodium and calcium and urea difficult or impossible, an especially serious limitation when sample size must be restricted. In samples at room temperature without preservative, plasma glucose decreased 36 mg/liter per hour in blood from adults and 60 mg/liter per hour in blood from newborns. Cooling on ice slowed these rates to 3.9 and 11, respectively. Plasma potassium increased 0.3 mmol/liter per hour in cooled specimens from both adults and newborns. Sodium, calcium, chloride and urea values were unaffected. We conclude that cooling effectively stabilizes plasma glucose for 4 h in samples from both adults and newborns and that potassium may be measured with negligible change for as long as 1 h and other constituents for the entire period.

Microscale modification of a cation-exchange column procedure for plasma ammonia

A column cation-exchange resin procedure for plasma ammonia was modified to require only 100 mul of plasma per determination. Mean analytical recovery of standard from resin (six samples) was 98% (range, 94-100%) as compared to a mean of 63% (range, 58-70) for nine samples when a batch cation-exchange procedure was used. Absorbance was proportional to sample concentration up to 800 mumol/liter. Analytical recovery of standard from plsma (six samples) was complete (mean, 103%; range, 90-113). Thirteen aliquots of a specimen of fresh plasma from a single adult individual gave a mean value of 20 mumol/liter (range, 11-26). The mean plasma venous ammonia concentration for 27 adults was 16 mumol/liter (range, 0-39), and for 15 newborns it was 60 (range, 34-102). Values for capillary plasma measured at the same time were higher, and we discuss possible explanations for this. Values are given for infants and children from one month to 14 years of age. Effects of storage time and temperature on plasma ammonia concentration are discussed.

Stabilization of blood glucose by cooling with ice: an effective procedure for preservation of samples from adults and newborns

Glycolysis causes a considerable decrease in blood glucose when whole blood is kept at room temperature without preservative. The most commonly used preservative, NaF, makes analysis of other serum constituents such as sodium and calcium and urea difficult or impossible, an especially serious limitation when sample size must be restricted. In samples at room temperature without preservative, plasma glucose decreased 36 mg/liter per hour in blood from adults and 60 mg/liter per hour in blood from newborns. Cooling on ice slowed these rates to 3.9 and 11, respectively. Plasma potassium increased 0.3 mmol/liter per hour in cooled specimens from both adults and newborns. Sodium, calcium, chloride and urea values were unaffected. We conclude that cooling effectively stabilizes plasma glucose for 4 h in samples from both adults and newborns and that potassium may be measured with negligible change for as long as 1 h and other constituents for the entire period.

Placental amino acid uptake. III. Transport systems for neutral amino acids

The human placenta is known to concentrate nearly all amino acids intracellularly for transfer to the fetus. To clarify the mechanism and regulation of this process we have determined the specificity of the principal placental transport systems for neutral amino acids. With the use of competitive inhibition techniques, three transport systems of overlapping specificity have been elucidated. These correspond approximately to the "A", "L", and "ASC" systems of Christensen and associates. In the placenta the specificity of these systems is as follows: A system - alpha aminoisobutyric acid (AIB), glycine, proline, N-methylalanine, alanine, serine, threonine, and glutamine; L system - isoleucine, valine, phenylalanine, BCH, alanine, serine, threonine, and glutamine; and ASC system - alanine, serine, threonine, and glutamine. Placental AIB uptake previously has been shown to increase with preincubation of tissue in vitro. This increase has now been found to be limited to the A system. Activity of the other two systems is essentially unaffected, demonstrating that the transport pathways are separately regulated.

Erythrocyte porphyrin analysis in the detection of lead poisoning in children: evaluation of four micromethods

We evaluated four procedures for determination of erythrocyte porphyrin: double extraction with ethyl acetate/acetic acid-HCl, single extraction with ethanol, single extraction with acetone, and direct solubilization with detergent-buffer. The ethyl acetate procedure, when used with two portions of HCl, apparently gives complete recovery of porphyrin and is suitable for reference as a comparison method. The ethanol procedure gives a high and consistent recovery and is technically simpler. The acetone procedure gives low and variable recovery of porphyrin, and the detergent-buffer method is subject to serious hemoglobin interference; neither of these two procedures offers any technical advantage. Stability of samples and methods for standardization were explored. A procedure for expressing results in terms of erythrocyte Zn-protoporphyrin content is given. Because of its stability, coproporphyrin is useful as a daily working standard. The ethyl acetate and ethanol methods are about equally efficient for detecting lead intoxication. Because of its simplicity, the ethanol method seems to be the best for use in screening.

The nonuniform distribution of acidic components on the human placental syncytial trophoblast surface membrane: a cytochemical and analytical study

The surface coat of syncytial trophoblast from term human placentas was studied using cytochemical methods (colloidal iron, alcian blue-lanthanum nitrate, dialyzed iron) in coordination with tissue enzyme digestions (trypsin, neuraminidase) and sialic acid analyses. The presence of at least two highly acidic anionic components that contribute significantly to the surface negativity of trophoblast has been demonstrated. The first of these, sialic acid, was removed with neuraminidase. Tissue digestion with this glycosidase was accompanied by a decrease in trophoblast surface staining with colloidal iron, a decrease in tissue sialic acid, and an increase in the concentration of sialic acid in the incubating medium. Results from methylation experiments were consistent with the presence of sialic acid. The second anionic component(s) was identified by removal with trypsin of a glycocalyx constituent that stained with both colloidal iron and lanthanum. After trypsinization, tissue sialic acid levels were not significantly different from control values, and no detectable sialic acid was present in the incubating medium. The identity of this anionic component has not been established. Both sialic acid and nonsialic acid acidic components are distributed in higher density on membrane of microvilli than on intermicrovillous surface membrane. In addition, the sialic acid moieties appear to be clustered in the glycocalyx.

Erythrocyte porphyrin analysis in the detection of lead poisoning in children: evaluation of four micromethods

We evaluated four procedures for determination of erythrocyte porphyrin: double extraction with ethyl acetate/acetic acid-HCl, single extraction with ethanol, single extraction with acetone, and direct solubilization with detergent-buffer. The ethyl acetate procedure, when used with two portions of HCl, apparently gives complete recovery of porphyrin and is suitable for reference as a comparison method. The ethanol procedure gives a high and consistent recovery and is technically simpler. The acetone procedure gives low and variable recovery of porphyrin, and the detergent-buffer method is subject to serious hemoglobin interference; neither of these two procedures offers any technical advantage. Stability of samples and methods for standardization were explored. A procedure for expressing results in terms of erythrocyte Zn-protoporphyrin content is given. Because of its stability, coproporphyrin is useful as a daily working standard. The ethyl acetate and ethanol methods are about equally efficient for detecting lead intoxication. Because of its simplicity, the ethanol method seems to be the best for use in screening.

Positive physiotherapy following keller's operation

It is stated that hallux valgus is the commonest of all deformities of the feet and that the operative procedures to correct this have a bad public reputation, though results are good (Wiles and Sweetnam, 1965).