Mistletoe lectin I binding sites on the synaptosomes of the rat cerebral cortex

By means of combined lectinological and immunological methods were demonstrated mistletoe lectin I binding sites on rat cerebral cortex synaptosomes. The mistletoe lectin I binds specifically D-galactose. Galactosyl residues were established on the junctional and nonjunctional synaptosomal membrane, on the synaptic vesicles, mitochondria and on myelin contamination. The relative number of mistletoe lectin I receptors per unit area of synaptosomal membrane was calculated.

Plasma clearance, tissue distribution and catabolism of cationized albumins with increasing isoelectric points in the rat

The infusion of cationic substances produces acute renal failure and proteinuria, and an experimental disease very similar to disseminated coagulopathy. The purpose of this work was to investigate further, in the rat, the plasma disappearance rate, the tissue distribution and the catabolism of albumins with modified isoelectric points. Human serum albumin was cationized with hexanediamine and labelled with 125I or 131I. During 10-180 min after their intravenous injection into the rat, these modified 125I-labelled albumins were cleared from the plasma at a rate which increased with their isoelectric point. At 1 and 3 h after the injection of highly cationic proteins (isoelectric point higher than 9.5) the tissue protein bound 125I concentration was greatest (approximately 3.5% of the injected activity/g) in the spleen and liver. A significant amount of the basic proteins was found in the kidney and in the lung (0.75-1%/g). Their concentration was much lower in other tissues. The whole body radioactivity was significantly lower 24 h after the injection of 131I-labelled cationized albumins than after similarly labelled native albumin. However, expressed as a percentage of the retention at 24 h, the body radioactivity at later times was higher for cationic than for native albumin. We conclude that cationized albumins are cleared from the plasma, mainly by the reticuloendothelial system, at a rate directly related to their isoelectric point. The cationized albumins are catabolized very rapidly initially, but a fraction of the injected protein remains in the body for a longer time than native albumin.

Mapping of transfer RNA genes on tobacco chloroplast DNA

Tobacco chloroplast tRNAs have been purified by two-dimensional polyacrylamide gel electrophoresis, identified by aminoacylation, labelled at their 3'-end and hybridized to tobacco chloroplast DNA restriction fragments, in order to establish a tRNA gene map. These hybridization studies have revealed the localization of at least seven genes in each inverted repeat region, a minimum of 22 tRNA genes in the large single copy region and one tRNA gene in the small single copy region. Comparison of the tobacco chloroplast tRNA gene map to that of maize shows many similarities, but also some differences suggesting that DNA sequence rearrangements have occurred in the chloroplast genome during evolution.

Comparison between the fractional isotopic calcium absorption and an oral calcium tolerance test

In 27 subjects with several disorders of calcium metabolism, the fractional intestinal absorption of 47CaCl2 was rather poorly correlated with the urinary output of calcium or with the maximal increase of serum calcium after an oral calcium load. Conversely, a good correlation was observed with the product of these parameters. We propose that this product be used as an estimate of intestinal calcium absorption when a radioisotopic method is not available.

Regional measurement of bone calcium accretion rate and exchangeable pool with a whole-body counter: method and studies in subjects without bone disease

A whole-body counter was used to measure the retention and distribution of radioactivity along the longitudinal axis of the body during 10 days after the intravenous injection of 50 microCi of 47Ca. These data and the simultaneous measurements of the serum specific activity allowed us to calculate, by the Bauer-Carlsson-Lindquist (BCL) formulas generalized by Marshall, the calcium accretion rate and exchangeable pool in 7 areas: skull, thorax, pelvis, thighs, knees, legs, and ankles and feet. For the whole body, the accretion rate was 336 +/- 115 mg/24 h, and the exchangeable pool 5668 +/- 1221 mg, in 26 subjects without bone disease. Both parameters were significantly correlated with body height; the exchangeable pool was significantly higher in men than in women. The accretion rate and exchangeable pool expressed on a basis of bone content varied widely from one area to another, reflecting the ratio of spongy to compact bone: the thorax, pelvis, and arms, which contain 49% of the skeletal mass, accounted for 57% of the total accretion rate and 53% of the exchangeable pool; the skull, 18% of the skeletal mass, accounted for 14% of the accretion and 11% of the pool.

Bone mineral content in idiopathic renal stone disease and in primary hyperparathyroidism

Bone mineral content (BMC) was measured with the Norland Cameron apparatus in 120 renal stone formers (RSF) with idiopathic stone disease and in 41 patients with primary hyperparathyroidism. RSF were classified, according to an oral calcium load test, into three groups: no hypercalciuria (HC; 41 cases); absorptive HC (53 cases), and resorptive or renal HC (25 cases). BMC values in RSF as a group were significantly lower than normal (p less than 0.001, Mann-Whitney test) though higher than in hyperparathyroid patients. There was a trend for BMC to decrease from male RSF without HC to patients with renal or resorptive HC. No statistical difference was found between the groups, however, BMC values in absorptive HC were different from normal (p less than 0.001). Why patients with HC are demineralized is unclear since no correlation was found between BMC and basal values of serum phosphate, TRP, calculated TmP/GFR, urinary calcium or hydroxyproline. Nevertheless our results indicate that urolithiasis, and possibly its treatment, is not a benign condition for the skeleton.

Whole body and regional retention of 99mTc-labeled pyrophosphate at 24 hours: physiological basis of the method for assessing the metabolism of bone in disease

The retention of 99mTc-labeled pyrophosphate (PPi) at 24 h was measured in 235 patients, 119 of whom had a normal bone metabolism. The mean retention in the group of normal subjects is 52% of the injected dose. Reproducibility of the measurement in a given person is 5.5% coefficient of variation (CV). The value depends strongly on sex (higher in males) and age (higher with increasing age, especially in cortical bone). Retention increases slowly with the decrease in glomerular filtration rate (GFR) between 50 and 120 ml/min; it rises very rapidly with values below 50 ml/min. The slowing down of the GFR with age does not account for the increase in PPi retention with age. When expressed as a percentage of the expected value for sex and age, retention is frequently low in osteoporosis (P less than .001), more so when urinary hydroxyproline is low; it is normal or high in osteomalacia, and in some cases rises after vitamin D treatment is started; it is high in hyperparathyroidism (P less than .01). The PPi retention is correlated with bone calcium accretion rate, alkaline phosphatase level, and above all, the urinary hydroxyproline level. The lower the bone mineralization (Ca/hydroxyproline ratio in biopsy), the higher the retention value. We conclude that the PPi retention is an index of bone metabolism when GFR is higher than 50 ml/min. It allows for classification of metabolic bone diseases according to the bone turnover rate. It has the advantage over the usual biologic examinations in that it affords better observation of highly localized bone disorders and can be used in combination with a morphologic record, the bone scintigraphy.

Electron microscopic demonstration of negative surface charges on cytoplasmic membranes of Bacillus subtilis with protamine-ferritin

The application of a protamine-ferritin conjugate for labelling of isolated protoplast membranes of Bacillus subtilis S 13/1 is described. Contrary to Mycoplasma membranes which could only be labelled on the outer side of the membrane, ferritin was deposited on both membrane sides as a single layer without cluster formation.

Combination of immunological and lectin reactions in affinity histochemistry: proposition of the term affinitin

Using the series system cell receptor leads to mistletoe lectin leads to antiferritin-antibody leads to ferritin, the possibilities for combination of lectin and immunological reactions for histochemistry are discussed. The system cell antigen leads to antibody leads to labelled mistletoe (or other) lectin is recommended for visualization of cell antigens (mistletoe lectin as common immunoglobulin reagent). It is pointed out that lectin reactions do not belong to immunhistochemistry but to affinity histochemistry. For all receptor specific proteins (antibodies, lectins, enzymes, haptoglobin and other) the term affinitin is proposed. In consideration of this new definition a common scheme is formulated: Affinitin reacts with affinitin receptor forming affinity product.

Bone blood flow measured by 85 Sr microspheres and bone seeker clearances in the rat

This paper investigates further the relationship between the initial bone clearance of a bone-seeking radioisotope or labeled substance and the bone blood flow. The bone blood flow of rats was modified over the widest possible range of physiological values by heating and cooling their hindlimbs. Osseous blood flow was measured by the arteriolar trapping of labeled microspheres of 15 micrometer diameter injected into the left ventricle. The plasma clearances of 45Ca and 99 m Tc by bone were measured 10 min after the intravenous injection of radiocalcium and of 99 m technetium pyrophosphate. The extraction ratio for 45Ca over the 10-min interval (45Ca clearance/bone plasma flow) was 0.60 for low blood flows, 0.40 for blood flows at rest, and 0.25 for high values of flow. The data for 99 m Tc were, respectively, 0.68, 0.34, and 0.22. Initial bone clearances of either substance should not be used to measure the increases in bone blood flow over the values at rest.

Longitudinal study of calcium and bone metabolism in paraplegic patients

A longitudinal study of bone and calcium metabolism in 28 patients with spinal chord lesion shows an enhancement of bone calcium accretion, generalized to the whole skeleton. The bone calcium turnover rate is more increased in the non-paralysed area during the first 2 months.

Respiratory failure and cardiac disturbances in myotonic dystrophy

Cardiopulmonary abnormalities are frequently encountered in myotonic dystrophy. We present five patients with myotonic dystrophy who entered the intensive care unit in acute respiratory failure. The possible etiologic factors of pulmonary complications are reviewed. The most important is probably aspiration pneumonia. The difficulties in the treatment of the respiratory failure are emphasezed. Myotonia of the chest muscles and diaphragm make artificial ventilation difficult. Recovery is delayed chiefly by swallowing disturbances. General anaesthesia is hazardous. Four patients presented cardiac arrhythmias and/or conduction abnormalities which were transient.