Human myeloid alpha 3-fucosyltransferase is involved in the expression of the sialyl-Lewis(x) determinant, a ligand for E- and P-selectin

The sialyl-Lex determinant (NeuAc alpha 2-->3Gal beta 1-->4[Fuc alpha- 1-->3]GlcNAc) has been identified as a major ligand in the selectin- mediated adhesion of neutrophils and monocytes to activated endothelium or platelets. This carbohydrate epitope is formed by the sequential action of alpha 3-sialyltransferase and alpha 3-fucosyltransferase on N- acetyllactosamine (Gal beta 1-->4GlcNAc) disaccharide termini of glycoconjugates. We have addressed the role of the human myeloid alpha 3-fucosyltransferase in the expression of this epitope at the leucocyte surface by determining its activity in human-mouse leukemic cell hybrids (WEGLI), normal human granulocytes and chronic myeloid leukemia (CML) cells using sialylated and desialylated glycoproteins and oligosaccharides as acceptor substrates. In contrast to what has been reported for the myeloid-type enzyme, we found that the alpha 3- fucosyltransferase of the cells studied can use sialylated acceptors be it that the activity is several times lower than with asialo- substrates. Characterization of the product obtained with a sialylated oligosaccharide indicated that the enzyme can catalyze the formation of the sialyl-Le(x) structure. Flow cytometry of the WEGLI cells using a sialyl-Le(x)-specific monoclonal antibody (MoAb) showed that these cells indeed express sialyl-Lex at their surface, provided that they contain human chromosome 11. Earlier the presence of this chromosome had been correlated with the expression of alpha 3-fucosyltransferase activity. In addition to sialyl-Le(x), WEGLI cells containing chromosome 11 showed high-expression levels of related structures recognized by antibodies VIM-2 and VIM-8, suggesting that fucose addition can occur at both distal and proximal GlcNAc residues in poly- N-acetyl-lactosaminoglycan sequences. Based on the human chromosome contents it could be ruled out that the alpha 3-fucosyltransferase of WEGLI cells is a Lewis-type alpha 3/4- or plasma-type alpha 3- fucosyltransferase, the genes of which have been mapped to chromosome 19. It is concluded that the enzyme studied is of the myeloid-type and indeed is involved in the synthesis of sialyl-Le(x) (and also VIM-2 and VIM-8 structures) in leukocytes provided that its expression is at a sufficiently high level.     

Reduction of sound levels with antinoise in MR imaging

A combination of active and passive techniques was used to reduce the sound levels in magnetic resonance imagers. These techniques were integrated into an existing audio system. Measurements of sound reduction varied with the protocol being used and averaged 9.9 dB with coaxial cabling and 14.2 dB with fiberoptic conduction of the feedback signal to a controller. Patient comfort and communication were improved.     

A phenomenological difference between membrane skeletal protein complexes isolated from normal and hereditary spherocytosis erythrocytes

S ummary . Membrane skeletons may be obtained from human erythrocytes by extraction with non-ionic detergent. When treated under defined conditions with a cAMP-independent kinase preparation from normal membranes, a suspension of these membrane skeletons sets to a gelatinous mass. Membrane skeletons from the cells of hereditary spherocytosis patients fail to show this response. Those from subjects with some other haemolytic anaemias do not share the abnormality. The gelation process could be shown also to occur with normal membrane skeletons, extracted at high ionic strength, and containing essentially only the structural protein constituents, spectrin, actin, 4·1 and 4·9. It also occurred rapidly when a column-purified kinase preparation was used, so that no significant amounts of contaminating proteins were introduced. Added spectrin, 4·1 or actin in moderate amounts did not induce gelation in the presence of ATP. Cytochalasin E did not perturb the gelation process. Gelation required ATP as well as kinase, and did not occur when the non-hydrolysable analogue, AMP-PNP, was used instead. Gelation was accompanied by phosphorylation of the spectrin alone, and is thus evidently a consequence of the modification of its properties by this means. Inhibition of phosphorylation by added adenosine retarded gelation. It may be inferred that phosphorylation of spectrin generates new, probably weak, non-covalent interactions between cytoskeletal constituents that cause association of the isolated cytoskeletons. A semi-quantitative method of observing the gelation process, based on the time of incubation before the membrane skeleton suspension ceases to flow under gravity a t a low shear. is described.     

Retrograde pancreatic duct imaging and surgical tactics in hemorrhagic necrotizing pancreatitis. Preliminary report

In patients with haemorrhagic necrotizing pancreatitis who are scheduled for surgery we have been carrying out a preoperative retrograde investigation of the pancreatic duct system for the past months. The results in, to date, ten patients revealed four different morphological findings of importance for the surgical tactic: 1. A normal pancreatic duct system with no signs of fistulae: only peripancreatic necrosectomy is required. - 2. Contrast medium leaks via a ductal fistula: left resection including the removal of the fistulous area must be done. - 3. Normal duct system with complete segmental parenchymal staining, representing total necrosis in this region: left resection of the pancreas. - 4. Duodenoscopically demonstrable perforation into the duodenum of a necrotic cavity in the head of the pancreas: conservative management only, no surgery, since this lesion resulting in drainage of the necrotic cavity into the bowel permits self-healing, while the site of the perforation within the necrotic wall cannot be dealt with by surgery. - The experience gained so far indicates that the surgical tactic can be determined with greater selectivity by the use of ERP.     

Fast recording ion specific microelectrodes: Their use in pharmacoeogical studies in the CNS

Steady state levels and transient rises and decreases of intracortical potassium activity were measured with ion specific microelectrodes. Resting intracortical K⁺ activity was low and most probably reflected that of the extracellular volume. Pentobarbital and diphenylhydantoin had a decreasing effect on stimulation-induced K⁺ increase. This was also found during electrophoretic injection of γ-aminobutyric acid. Dibutyric cyclic adenosine monophosphate and norepinephrine had relatively small or no depressing effects. Glutamate injection led to an increase in [k⁺]₀. Pharmacological evidence indicates that [k⁺]₀ rise is related to excitability changes of terminal afferents but not to dorsal root potentials and presynaptic inhibitory processes in the lumbar spinal cord.No pharmacological evidence for the mediation of an observed “primary” stimulus-induced decrease of [K⁺]₀ in cortex was found.An example of the application of chloride specific microelectrodes in intracellular measurements is given.     

Gender differences in 24-hour urinary diaries of asymptomatic North American adults

PURPOSE: Two previously published studies from our center have described the urinary habits of asymptomatic men (284) and women (300) as revealed by 24-hour urinary diaries. Those gender specific studies found that urinary diary variables are affected by age and race. By comparing the data from those studies we determined the effect of gender on voiding habits. MATERIALS AND METHODS: In this secondary analysis we matched each female urinary diary to that of a male of similar age and race. Diary variables were compared using paired sign tests with results considered significant at the 5% level. RESULTS: A total of 141 matched pairs were studied. The population age ranged from 18 to 68 years and was racially diverse (56% black, 31% white, 7% Hispanic and 6% Asian). Men had higher total fluid intake and mean voided volume than women (p <0.001 and 0.04, respectively). Women voided more frequently than men (p = 0.006) and had more voids per liter of fluid intake (p <0.001). No gender differences were found for body mass index, nighttime or daytime diuresis rates, total urine volume, maximum voided volume or rates of nocturia. CONCLUSIONS: This analysis suggests that there are significant gender effects on 24-hour diary variables, with females tending to void more often and at lower mean volumes. The results of our study may be useful in the design of research studies or for patient counseling.     

Ökonomische Aspekte der Gesundheitstelematik

Zusammenfassung Die ökonomischen Aspekte der Gesundheitstelematik sind aus 2 Blickwinkeln zu betrachten. Administrative Applikationen eignen sich gut als Startapplikationen, da ihre Datenstrukturen und Prozesse gut bekannt sind und sich die jeweiligen monetären Effekte auf einer soliden empirischen Basis ermitteln lassen. Jedoch werden erst die medizinischen Applikationen das wahre Potenzial einer Gesundheitstelematik ausschöpfen und deren politischen wie auch finanziellen Aufwand rechtfertigen.     

Morbid obesity treated by gastroplasty: radionuclide gastric emptying studies

Mechanisms by which gastroplasty for morbid obesity causes weight loss are poorly understood. We studied the role of altered gastric emptying in 50 patients before surgery, 1-4 weeks after surgery, and 2-24 months after surgery using technetium-99m pentetate in water for liquid meals and a Tc-99m styrene divinylbenzene copolymer resin in oatmeal for semisolid meals. We determined the emptying half-times of the stomach before and after surgery in the proximal and distal compartments. The proximal compartment emptied promptly in the early and late postoperative periods. The distal compartment emptied liquids at rates similar to those before surgery, while the late postoperative emptying of semisolids was significantly faster. The stoma connecting the two compartments thus permits rapid transit of liquids and semisolids without delay of distal compartment emptying. No correlation was seen between the emptying half-times or changes thereof and eventual weight loss. Delayed gastric emptying is therefore not the mechanism for satiety and weight loss after gastroplasty has been performed.