Direct Observation of Chemical Bond Dynamics on Surfaces

The dynamics of chemisorbed species as they swing to-and-fro on their adsorption sites may be directly observed with electron-stimulated desorption. The observation of the thermal disorder in adsorbate chemical bond directions, through studies of the thermal excitation of librational modes, allows one to visualize the potential energy surfaces controlling the structure and dynamics of adsorbates on single crystal metal and semiconductor surfaces. This information may be useful in understanding surface diffusion as well as the spatial aspects of surface chemical reactions.

Changes in plasma and urinary amino acid levels during diabetic ketoacidosis in children

Plasma and urinary concentrations of different amino acids were investigated during diabetic ketoacidosis (DKA) and 12, 24, 72 hours after initiation of therapy. In DKA, plasma concentration of glutamic acid, aspartic acid, valine, leucine and isoleucine significantly increased while that of asparagine and glutamine decreased compared to levels in well-controlled diabetic patients. The urinary excretion of branched-chain amino acids, histidine, serine and threonine was elevated while those of glutamic acid, glutamine, glycine and taurine were reduced. Among the different amino acids, histidine excretion had the highest variability. A strong correlation was found between the urinary excretion of several amino acids and that of the beta-2-microglobulin characterizing tubular dysfunction. Changes in the excretion of different amino acids reflect the altered metabolic state and renal function due to DKA.

Comparative study of acetylcholine synthesis in organs of freshwater teleosts

The activity of acetylcholine (ACh) synthesizing enzyme, choline acetyltransferase (ChAT), and the content of ACh were determined in the brain, heart, red trunk muscle and midgut of 12 freshwater teleost species belonging to eight families: carp (Cyprinus carpio), tench (Tinca tinca), silver carp (Hypophthalmichtys molitrix), bighead (Hypophthalmichtys nobilis), wels (Silurus glanis), cat fish (Ictalurus nebulosus), eel (Anguilla anguilla), rainbow trout (Oncorhynchus mykiss), pike (Esox lucius), pike-perch (Stizosteidon lucioperca), ruffe (Acerina cernua) and pumpkinseed (Lepomis gibbosus). The rate of ACh degradation in the same tissues was characterized by measuring the activity of acetylcholinesterase (AChE). Comparisons by statistical evaluation of cholinergic parameters in the corresponding organs were made between the species or families. The highest ACh concentration was found in the brain (between 9.6 and 16.0 nmol/g), and the gut (4.6 to 17.4 nmol/g), followed by the heart (1.4 to 3.9 nmol/g) and trunk muscle (1.2 to 3.8 nmol/g). Good correlations were found between the ACh content and the ChAT activity in all the organs studied. The correlation coefficients were 0.92 and 0.72 for the brain and heart, respectively. The activity of ChAT and the amount of ACh found in the brain and trunk muscle varied considerably from one family to another, but was of comparable degree within one family. It was concluded that differences in the cholinergic parameters may reflect different feeding and swimming behavioral patterns.

[T-lymphocyte subgroups and the activity of human natural killer cells in non-Hodgkin lymphoma of moderate and high malignancy]

T-lymphocyte subgroups and the percentage and the activity of Human Natural Killer cells (HNK) were investigated by the authors in their 24 patients suffering with low grade and 24 with high grade malignancies of non-Hodgkin lymphoma (NHL). According to their observations, the ratio of CD3, CD4, Leu-7, and HNK cells as well as the release by HNK cells of 51Cr bound to target cells decreased, depending on the pathological stage. The tests were performed with monoclonal antibodies. A significant change could also be observed in the reactivity of bone marrow cells to monoclonal sera, which showed complete correspondence in character with the behavior of lymphocytes isolated from peripheral blood. No significant changes could be observed in the quantitative relations of immunoglobulins. Discussing the supposed immunological relation in detail, the role of plasma factor that reduces the formation of T-lymphocytes, is assumed to have primary importance in this phenomenon.

Reduced glomerular filtration and elevated urinary protein excretion in diabetic ketoacidosis

Glomerular filtration rate (GFR) was measured by two methods in 9 children with diabetic ketoacidosis (DKA), directly by true creatinine clearance and indirectly by means of serum beta-2-microglobulin levels. We found significantly reduced GFR in the first hours of DKA. The rapid improvement in GFR after fluid and electrolyte replacement indicates that volume depletion is the major cause of low filtration rate. In spite of the reduced GFR we observed pronounced albuminuria and low molecular weight (LMW) proteinuria. We conclude that the pathological albuminuria and microalbuminuria in DKA are caused not by glomerular hyperfiltration but by tubular dysfunction.

[Follow-up of blood and urinary amino acid concentrations in diabetic ketoacidosis in children]

Plasma and urinary concentrations of amino acids were investigated during diabetic ketoacidosis (DKA) and 12, 24, 72 hours after initiation of therapy. In DKA plasma concentration of glutamic acid, asparaginic acid, valine, leucine and isoleucine significantly increased while that of asparagine and glutamine decreased compared to levels in well controlled diabetic patients. Despite the elevated urinary excretion of branched chain amino acids, histidine, serine and threonine, urinary excretion and clearance of glutamic acid, glutamine, glycine and taurine were reduced. Among the different amino acids histidine excretion had the highest variability. Strong correlation was found between the urinary excretion of several amino acids and that of the beta-2-microglobulin characterizing tubular dysfunction. Changes in the excretion of different amino acids reflect the altered metabolic state and renal function due to diabetic ketoacidosis.

Urinary prostaglandins in hyperglycaemic ketoacidosis of type I diabetes mellitus

Urinary excretion of various renal prostaglandins was measured by radioimmunoassay and gas chromatography-mass spectrometry in children who had different degrees of metabolic control. Excretion in PGE2 in diabetic children was twice control values irrespective of the presence or absence of diabetic ketoacidosis (DKA). The urinary excretion of PGF2 alpha was significantly increased in diabetic children with ketoacidosis, but not when diabetes was well controlled. The excretion of 13, 14 dihydro-15-keto PGE2, the major metabolite of circulating PGE2, was increased in all diabetic children, and was most elevated in ketoacidosis when it averaged 10 times basal excretion. Urinary excretion of PGF2 alpha and of 6-keto-PGF1 alpha, the metabolite of PGI2, was approximately doubled in DKA compared with values from healthy subjects. Excretion of PGE2 was twice control values in children with stable diabetes, whereas the equivalent value for TXB2, the metabolite of the active vasoconstrictor TXA2, was reduced by approximately 50%. We suggest that the increased excretion of prostacyclin metabolite may result from a protective biological action on the kidney opposing other vasoconstrictor hormone activity. PGE2 appears not to be involved in this process. The highly elevated excretion of PGE2 metabolite may represent an activation of systemic PGE metabolism during DKA.

Hypertension screening in a Hungarian town

In conjunction with a radiological tuberculosis project, a hypertension screening programme was carried out in 1984 on 13,772 people (74% of the eligible adult population) in the Hungarian town of Csongrád. In the younger age groups the blood pressure was found to be higher amongst men, whilst in older groups the women had higher blood pressures. By the WHO criteria, systolic hypertension was detected in one-third of the population and diastolic hypertension in one-sixth. Of the hypertensive patients detected, 34% were previously unaware of their diagnosis. The prevalence of hypertension was elevated particularly amongst obese persons and in the sub-group of physical (blue collar) workers aged over 60 years. There was a significant correlation between alcohol consumption and both systolic and diastolic blood pressures. Hypertension was found in 29.9% of heavy drinkers but in only 20.5% of moderate drinkers or total abstainers.

[Determination of the degree of saturation of calcium hydrogen phosphate in the urine]

Calcium-hydrogen-phosphate (CaHPO4) was considered as one of the main factors governing renal calculus formation. The degree of saturation (expressed as activity product) with respect to this phase was therefore calculated in urines of 36 hypercalciuric children (20 absorptive, 16 renal subtype) with isolated hematuria, 10 renal stone patients, and 30 healthy controls. On low calcium diet 12 children of the absorptive hypercalciuric-, 13 of the renal hypercalciuric and 7 of the renal stone forming children hat their urines in the saturated zone --irrespective of the evolution of hypercalciuria Ca/cr ratio. Thiazide normalised the activity product in all groups. The use of the Ca/cr ratio as the sole parameter in the investigation of children with isolated hematuria and hypercalciuria or calcium nephrolithiasis is therefore insufficient, simultaneous determinations of the state of saturation of urines is recommended. This technique should also allow a quantitative assessment of the various therapeutic regimens recommended.

Comparison of effects of paraquat and methidation on enzyme activity and tissue necrosis of carp, following exposure to the pesticides singly or in combination

Under aquarium conditions, treatment with the herbicide paraquat (PQ) and with the insecticide methidation (MD) caused cell damage and stress in carp (Cyprinus carpio L.), as shown by increases in glutamate-dehydrogenase (GIDH, EC 1.4.1.2), glutamate-oxalacetate transaminase (GOT, EC 2.6.1.1) and lactate dehydrogenase (LDH, EC 1.1.1.27) activities and in blood sugar levels. PQ proved synergistic with MD in certain cases as regards the harmful effect exerted. On combined treatment, dilated extracellular spaces were visible by light microscope in the liver, while electronmicroscopic studies revealed signs indicative of cell autolysis in the same organ.

Diminished parathyroid 1,25(OH)2D3 receptors in experimental uremia

In Sprague Dawley rats, six days after subtotal nephrectomy, serum 1,25(OH)2D3 concentration was diminished (59.8 +/- 17.5 pg/ml vs. 121 +/- 48; P less than 0.01). Despite low circulating 1,25(OH)2D3 levels, maximal specific binding capacity for 1,25(OH)2D3 in parathyroid glands was diminished (Nmax 87.5 fmol/mg protein and 3.52 fmol/mg DNA vs. 143 fmol/mg protein and 4.75 fmol/mg DNA, respectively). There was no change of KD, apparent molecular size (sucrose density gradient) and DNA binding affinity (DNA cellulose chromatography) pointing to intactness of the receptor. Since 1,25(OH)2D3 is a potent negative feedback signal for parathyroids, the data are potentially relevant for the genesis of secondary renal hyperparathyroidism.

1,25(OH)2D3 receptors and endorgan response in experimental aluminium intoxication

Severe aluminium-induced osteomalacia is refractory to treatment with 1,25(OH)2D3 which frequently causes hypercalcemia. To further explore the mechanisms involved, we have utilized a model of short-term aluminium intoxication in the rat (total: 11 mg elemental aluminium in 3 weeks) to study (a) 1,25(OH)2D3 receptor status in a variety of classical and non-classical target organs for 1,25(OH)2D3; (b) circulating 1,25(OH)2D3 levels; (c) baseline duodenal calcium transport, utilising the Ussing chamber, to investigate the functional significance of receptor status in a classical target organ; and (d) duodenal calcium transport response to exogenously administered 1,25(OH)2D3. Both in the three week model and in the 16 week model (total: 41 mg elemental calcium) increased maximal specific binding capacity for 1,25(OH)2D3 (Nmax), that is, number of unoccupied receptors, was observed in nuclear fractions of all tissues studied. Receptor affinity, the apparent dissociation constant KD, was unchanged. Total binding capacity, measured after displacement of endogenous ligand by Mersalyl, that is, the sum of occupied plus non-occupied receptors, was also increased. Both circulating 1,25(OH)2D3, mucosa-to-serosa calcium flux (Jms) and net calcium flux (Jnet) were reduced under baseline conditions, suggesting the lack of a direct relationship between receptor expression and endorgan response. Following exogenous 1,25(OH)2D3 administration, calcium Jms and Jnet were significantly lower in the aluminium intoxicated animals, with the increment induced in Jnet in aluminium intoxicated animals being 63% of that induced in controls. Our data suggest that resistance to the action of 1,25(OH)2D3 in aluminium intoxication is postreceptor in nature.

Studies on the urinary calcium excretion in children with hematuria of postglomerular origin: effects of the variation of dietary calcium and sodium intake

The effect of different dietary regimens and of an oral calcium (Ca) load was studied in 30 children with postglomerular hematuria, 8 of whom were renal stone formers. In addition we investigated the urinary inorganic phosphate complex composition in 12 of them, based on the principles of complex equilibria. Twenty-one of the 30 hematuric children with a urinary Ca/creatinine (Ca/cr) ratio of greater than or equal to 0.6 (mmol/mmol) were regarded as hypercalciuric. Low calcium intake normalised the ratio in 11 patients, fulfilling the definition of absorptive hypercalciuria, but not in the other 10 patients with renal hypercalciuria. Sodium restriction combined with low calcium diet induced a further significant decrease of the urinary Ca/cr ratio to a normal range in both forms of hypercalciuria (mean +/- SD: 0.325 +/- 0.112 in absorptive hypercalciuria; 0.533 +/- 235 in renal hypercalciuria). There was a significant difference in the composition of phosphate complexes between the 6 normocalciuric patients and the 6 children with renal hypercalciuria investigated. Lithogenic urinary phosphate complexes (CaHPO4, MgHPO4) were excreted by the latter group in a significantly higher amount under basal conditions. On the basis of these data sodium restriction added to low calcium diet could represent a dietary approach in preventing excessive calcium excretion in idiopathic hypercalciuria, and therefore renal stone formation.

Hyperinsulinuria in diabetic ketoacidosis

Urinary insulin excretion has been measured in diabetic children. In nine well controlled diabetics urinary insulin excretion (mean and 2SD) was significantly greater than that found in healthy controls (8.8; 4.4-17.5 versus 3.8; 2.3-6.4 microU/min/1.73 m2). In ten ketoacidotic diabetic children a 50 fold increase of the urinary insulin excretion has been observed (464.8; 158.2-1363 microU/min/1.73 m2). The hyperinsulinuria proved to be reversible: significantly decreased excretion rate (12.9; 9.7-12.3) could be measured 8-10 days after recovery from coma. The hyperinsulinuria during ketoacidosis indicates severe reversible tubular dysfunction. Recurrent ketoacidotic episodes might play a role in the development of diabetic nephropathy.

Tubular dysfunction in type I diabetes mellitus

Tubular function was investigated in patients with diabetic ketoacidosis and those with poorly controlled type I diabetes. Urinary excretion of beta 2 microglobulin and that of certain enzymes: gamma glutamyltransferase, leucine aminopeptidase, and N-acetyl-beta-D-glucosaminidase activities were significantly raised during ketoacidosis in 11 patients compared with healthy controls. In 13 poorly controlled diabetics, tubular electrolyte transport was studied and a significant reduction in tubular phosphate and sodium reabsorption was found. Tubular dysfunction occurring during diabetic ketoacidosis and in poorly controlled diabetics may contribute to the development of diabetic nephropathy.

Gamma-glutamyl transpeptidase activity in human urine

The gamma-glutamyl transpeptidase (EC 2.3.2.2) activity of the urine was determined in 369 cases, with L-gamma-glutamyl-p-nitranilide as substrate. Thermally stable, low molecular mass inhibitors were removed by dialysis. The enzyme activity was found to have a mean of 10.57 U/l for the normal neonate population, and a mean of 16.92 U/l for children. A significant increase in activity was observed in pyelonephritis, Alport's syndrome, Wilms' tumour and glomerulopathies. The highest activities were found in kidney diseases associated with renal insufficiency. This non-invasive test can be used for the evaluation of tubular disorders in childhood.

Local production of proteins in normal human bronchial secretion

Concentrations of albumin, IgG, IgA, IgM, alpha 1-acid glycoprotein, alpha 1-antitrypsin, alpha 2-macroglobulin, transferrin, haptoglobin, and coeruloplasmin were determined by radial immunodiffusion in the blood sera and bronchial washings of 8 patients without clinical, radiologic or bronchoscopic evidence of lung diseases. The local production of the proteins was calculated with a formula used by Deuschl and Johansson for the estimation of local synthesis of bronchial immunoglobulins. The formula was completed by a reduction factor established by the authors, based on their previous investigations. The calculations indicated that the individual proteins were secreted locally in various percentages of the total amount found in the secretion, as follows: IgG, 37%; IgA, 84.5%; transferrin, 44.5%, alpha 1-antitrypsin, 15.2%; coeruloplasmin, 11.3%. Local synthesis of IgM was found only in 3 patients. The alpha 1-acid glycoprotein and the haptoglobin do not seem to be secreted locally by the normal bronchial mucosa; they reach the mucus from blood only, through ultrafiltration.

Measurement of HBDH, CK and gamma-GT activities and comparison of the precision of four instruments used in kinetic analyses

A comparative analysis of low, normal and high activity of HBDH, CK, and gamma-GT was made using different kinetic measurement principles. The data revealed that the two-step integration technique and multi-point measurements evaluated by computer are essentially more accurate than the traditionally applied 3 x 1 minute enzyme determination.